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  • New Report Slams Idea of a Missile Defense Shield in Space

    WASHINGTON — It’s one of those ideas that never really goes away: The deployment of missiles in space to intercept ballistic missiles aimed at the United States and its allies. With North Korea testing ever more advanced nuclear weapons and delivery systems, the push to place interceptors in space is back in the conversation.

    Congress is asking the Pentagon to investigate the possibility. The National Defense Authorization Act for Fiscal Year 2018 authorizes the development of a “space-based ballistic missile intercept layer, capable of providing boost-phase defense.”

    Don’t do it, warns a new report by the Center for Strategic and International Studies. The think tank included space-based missile interceptors as part of its series titled “Bad Ideas in National Security.”

    This would be an attempt to resurrect the high-tech missile shield derided with the moniker ‘Brilliant Pebbles’ during the George H.W. Bush administration. The idea somehow has resurfaced after a hibernation period between Republican administrations, wrote Thomas Roberts, program coordinator and research assistant for the Aerospace Security Project at CSIS. [The Most Dangerous Space Weapons Concepts Ever]

    “Space-based missile interceptors are a bad idea because of their inefficiency and vulnerability,” said Roberts. “Investments in missile defense would be better directed to other, more effective areas.”

    From a political standpoint, the consequences of a space-based missile interceptor system would be troubling, Roberts said, as such a system would be seen as overt weaponization of space.

    Defending against a missile strike during the boost-phase is generally preferred but it presents the same challenge to space-based interceptors as it does for ground-based ones: having an interceptor close enough to the missile to respond when one is launched, Roberts explained. “The physics of orbital mechanics dictates that only interceptors in low-Earth orbit can reach a target missile in the required response time for a boost phase intercept — about 120 and 170 seconds for solid-and liquid-propelled missiles respectively.”

    Satellites in LEO are in constant movement over the surface of the Earth, meaning a large constellation of satellites is needed to ensure at least one is within range of a particular place on Earth at all times, Roberts noted. While satellites in geostationary orbit stay fixed over one area, at an altitude of more than 22,000 miles, they are simply too far away for an interceptor to reach a missile while it’s still in its boost phase.

    To defend against multiple missiles being launched at the same time — a salvo attack — several weapons must be within intercept range to provide effective coverage. Having a minimum of one interceptor available to strike a missile would require a constellation of hundreds of space-based interceptors, Roberts argued. Having multiple interceptors in position to defend against multiple missiles would mean thousands of interceptors in orbit. He cited a 2004 study by the American Physical Society suggesting that 1,646 satellites would be required for full-Earth coverage. The cost of such a system is estimated at $67 billion to $109 billion.

    One inherent weakness of a space-based missile shield is that the use of even a single interceptor can undermine the effectiveness of the remaining interceptors, Roberts noted. An adversary could both launch a missile to create a gap and later launch a second missile through the gap. Filling gaps in coverage would require back-up interceptors in orbit, waiting to take the place of an expended one, or the ability to launch new interceptors with short notice. These options would require a substantially greater investment than a minimal satellite constellation.

    Roberts said space-based interceptors could contribute to the greater missile defense complex by “thinning the herd” in a ballistic missile attack. But the physical constraints inherent to a boost phase intercept from orbit make it an impractical system to defend the United States and its allies. Investments in missile defense, he contends, would be better spent on adding a space-layer for tracking and target discrimination or additional land- and sea-based interceptors. The Outer Space Treaty does not prohibit placing conventional weapons like missile interceptors in space, as it does for nuclear weapons and weapons of mass destruction in general. “But the fact that it is not prohibited does not make it a good idea.”

    This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.

  • SpaceX's Jaw-Dropping Rocket Launch Wows Spectators Across Southern California

    Update: Check out more amazing SpaceX launch photos by our readers here: UFO? No, It’s a SpaceX Rocket! These Falcon 9 Launch Photos Are Just Amazing

    MISSION VIEJO, Calif. — Wow! Talk about some Friday night lights! A SpaceX Falcon 9 rocket lit up the evening sky over Southern California last night (Dec. 22) in a dazzling display that was visible to potentially millions of spectators and set Twitter abuzz with sightings. 

    The SpaceX Falcon 9 rocket launched into space from California’s Vandenberg Air Force Base north of Los Angeles at 5:27 p.m. PST (8:27 p.m. EST/0127 GMT) — just 30 minutes after sunset — carrying 10 Iridium Next communications satellites into orbit. The mission was a success, with all 10 satellites reaching their intended orbits. But it was the jaw-dropping views of the Falcon 9 streaking into space that stole the show, leaving an ethereal glowing plume in its wake as it soared into orbit. 

    “Caught off guard and had no idea what was happening at first …must say it was one of my life’s coolest moments!!!,” said Michelle Snyder, who watched the launch from the Hotel del Coronado in Coronado, California. She sent in the video shown above. “A forever memory with my daughters and parents who were in town visiting for the holidays. FOREVER MEMORY!!!

    From a southbound lane of the Interstate-5 freeway in Irvine, the launch wowed my 9-year-old daughter Zadie, who marveled at seeing the Falcon 9’s first stage separate from its upper stage (“I saw first stage separation? I saw stage separation!”) as we drove to meet relatives for the holidays. Her final say on the launch: “That is beautiful!”

    My daughter wasn’t alone in her awe. Observers across Southern California, and even as far away as Arizona and Tijuana, Mexico, reported stunning views of the launch.

    SpaceX CEO Elon Musk chimed in with a joke: “Nuclear alien UFO from North Korea,” he wrote in a video post of the launch on Twitter.

    Scroll down to see more spectacular views of the launch shared by observers.

    Enjoy those awesome views? We’ll try to share more as readers send in images, but SpaceX says its rocket launch shows will only get better.

    In one last Twitter post, Elon Musk promised even more spectacular views when SpaceX’s new heavy-lift rocket — the Falcon Heavy — begins launching in 2018. That rocket consists of three first-stage boosters, each of them based on the Falcon 9 first stage, that will separate and return to Earth much like the booster seen in Friday night’s launch.

    “If you liked tonight’s launch, you will really like Falcon Heavy next month: 3 rocket cores & 3X thrust. 2 cores return to base doing synchronized aerobatics. 3rd lands on droneship,” Musk wrote.

    The first Falcon Heavy test flight will launch in January from Pad 39A at NASA’s Kennedy Space Center in Cape Canaveral, Florida carrying Musk’s midnight cherry red Tesla Roadster into space (no really, here are the photos).

    So keep your eyes peeled in 2018!

    Editor’s note: If you captured an amazing photo of video of SpaceX’s Falcon 9 rocket launch and would like to share it with Space.com for a story or gallery, send images and comments in to: spacephotos@space.com. This story was updated at 10:42 a.m. EST to include the video and comments by Michelle Snyder from Coronado, California.

    Email Tariq Malik at tmalik@space.com or follow him @tariqjmalik and Google+. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

  • The Must-Read Space Books of 2017

    From Andy Weir’s follow-up book to “The Martian” to the view from space courtesy of British astronaut (and wrong-number-dialer) Tim Peake, Space.com brings you the spaceflight, space science, photo, science fiction and kids’ space books you should know about from 2017.

    For more, check out our Best Space Books and Sci-Fi pages, including Best Astronomy and Astrophysics Books, Best Spaceflight and Space History Books, Best Space Photography Books, Best Science Fiction and Best Space Books for Kids.

    Read on for this year’s finest!

    1. ‘Soonish’ (Penguin Press, 2017)

    By Kelly and Zach Weinersmith

    In “Soonish,” cartoonist Zach Weinersmith and biologist/podcaster Kelly Weinersmith delve into the future of technology with a comedic — but factually rigorous — trip through 10 technologies that could improve and/or ruin everything. While only some of those technologies relate to space, the Weinersmiths nevertheless give an in-depth glimpse into the future of spaceflight, building up a reader’s basic knowledge of the field and showing off the (sometimes bizarre) concepts that could let future spacefarers defy gravity, gather energy, power their machines and mine the solar system — all the while peppering the discussion with amusing comics and asides on some of the strangest spaceflight concepts. As Zach Weinersmith put it to Space.com: “I like to think we’re honest brokers for nerdy people interested in future stuff.” So pick this book up if you want an informative, entertaining and sometimes mindblowing guide to what the future might hold.

    Read our interview with Zach Weinersmith on the future of spaceflight here.

    2. ‘Planet Hunters’ (Reaktion Books, 2017)

    By Lucas Ellerbroek, translated by Andy Brown

    “Planet Hunters” takes readers through the history of the search for worlds around other suns  — from heretical belief to science fiction flight of fancy to one of the fastest-growing fields of astronomical research. Author Lucas Ellerbroek highlights the passion of exoplanet researchers as they learn about the countless planets circling other stars.

    “I really want to bring across the message that science is something not to be read purely in an encyclopedia, because encyclopedias change, and science is a dynamic enterprise done by humans,” Ellerbroek says of the book.

    Read an interview with the author here.

    3. ‘Amazing Stories of the Space Age’ (Prometheus, 2017)

    By Rod Pyle

    Spaceflight writer and historian Rod Pyle’s new book brings together tales of the most incredible and at times bizarre space missions ever conceived. Some of the missions and proposals discussed in the book will likely be well-known to space history buffs, but others are more obscure: Pyle dug deep to find mission concepts buried by history. There are stories of Wernher von Braun’s plans for sending humans to Mars, an idea backed by Freeman Dyson to create a nuclear-powered rocket (with the unfortunate side effect of increasing cancer rates among people living near the launch site), and a briefly considered proposal to build a military base on the moon in anticipation of the U.S. engaging in lunar battles with the Soviets. These stories provide a good perspective on just how many space missions ultimately fail for every one that succeeds.

    You can read an interview with author Rod Pyle here, and an excerpt from “Amazing Stories of the Space Age” here.

    4. ‘Chasing Space: An Astronaut’s Story of Grit, Grace, and Second Chances’ (Amistad, 2017)

    By Leland Melvin

    This astronaut’s memoir tells a truly inspiring story of how one unsuspecting football player from a small town in rural Virginia wound up flying in the Space Shuttle Atlantis on missions to the International Space Station. Leland Melvin started his career playing professional football in the NFL, but when an injury prevented him from playing, he went to school to become an engineer. It wasn’t until a recruiter from NASA grabbed his arm at a career fair that Melvin realized he could be an astronaut. He has since retired from the astronaut corps and now he dedicates his time to helping young women and minorities get involved in STEAM (science, technology, engineering, art and math) so they can realize and live up to their full potential.

    There is also a young readers’ edition of Melvin’s book, adapted to be a shorter and easier read than the adult book. It includes 16 pages of color photographs and three do-it-yourself experiments for kids to learn how to build small rockets and study the chemistry of candy.

    Space.com spoke with Leland Melvin about his incredible life story and work to make STEAM more diverse and inclusive here.

    5. ‘Making Contact’ (Pegasus Books, 2017)

    By Sarah Scoles

    Fifty years ago, only a handful of scientists were hunting for signals from other civilizations as part of the Search for Extraterrestrial Intelligence (SETI). In “Making Contact,” science writer Sarah Scoles explores the biography of one of the most influential SETI scientists, Jill Tarter. Scoles follows a mostly linear path through Tarter’s life, occasionally breaking into the present to bridge connections. While the biography traces the history of SETI, its primary focus is on Tarter: her childhood relationships with her parents that helped drive her, her education as the sole woman in her engineering class in the 1960s, and her struggle with scientists and bureaucrats who didn’t think hunting for alien signals was worth the time, money or resources. But Tarter continued to fight, helping to found a private agency that would survive government changes, hunting for private donors to look beyond this world and helping move the search for intelligent life from the fringes into mainstream science.

    Read an interview with Scoles about the book and Tarter’s life here.

    6. ‘Hello, Is This Planet Earth?’ (Little, Brown and Co., 2017)

    By Tim Peake

    British astronaut Tim Peake’s photo book takes its name from an unusual moment during his six months on the International Space Station — he tried to call his family on Christmas Eve in 2015, but dialed the wrong number instead, confusing the answerer with an unusual greeting: “Hello, is this Planet Earth?”

    The book is filled with Peake’s favorite photo selections of night and day, oceans and rivers, mountains and deserts,  towns and cities, and the Earth overall, as well as the satellites, cargo craft and other gear that made appearances during his time on the space station. His images are interspersed with descriptions of how he captured the photos and anecdotes about his time in space.

    Read more about the book here, and see a gallery of some of the book’s images here.

    Peake also wrote about his time in space in the memoir “Ask an Astronaut,” released this year as well; read an excerpt about his first spacewalk here and an interview with Peake here.

    7. ‘Artemis’ (Crown, 2017)

    By Andy Weir

    In “The Martian” (Crown, 2014) first-time author Andy Weir gave voice to the sardonic, resourceful botanist Mark Watney as he struggled for survival stranded on Mars. In his second novel, “Artemis,” he follows Jazz Bashara, a porter (and smuggler) on the moon who’s drawn into a crime caper. Weir brings a similar meticulous detail to his descriptions of the moon as the ultimate tourist destination as he did to Watney’s misadventures on Mars, but his characterization of Jazz doesn’t play to his writing strengths like Watney’s log entries did. Still, “Artemis” is an entertaining romp through a really intriguing future moon base, with plenty of one-sixth-gravity action and memorable twists. It’s well worth the read. Plus, there’s an audiobook version read by Rosario Dawson.

    Space.com talked with Weir about constructing a realistic moon base here.

    8. ‘Persepolis Rising’ (Orbit, 2017)

    By James S. A. Corey

    The “Expanse” series follows James Holden and the crew of his ship, the Rocinante, who seem to be in the middle of every key moment as Earth, Mars and the Asteroid Belt struggle for control and recognition. “Persepolis Rising,” the latest installment in James S.A. Corey’s “Expanse” series, is the beginning of the end for James Holden’s crew, setting a course for the final books of the series.

    Readers following Holden’s adventures thus far need no reminder to get this book — although maybe a reminder that it’s available, as the book’s authors keep up their feverish pace of about one book per year. Readers looking for a new science fiction series to binge-read, or those waiting on Season 3 of the Syfy Channel show based on the series, should check out the first novel, “Leviathan Wakes.”

    Read Space.com’s review here.

    Buy Persepolis Rising on Amazon.com

    9. ‘A Hundred Billion Trillion Stars (Greenwillow Books, 2017)

    By Seth Fishman, Illustrated by Isabel Greenberg

    Age range: 4-8

    In “A Hundred Billion Trillion Stars,” Seth Fishman Tackles the numbers that permeate everything around us. Not just any numbers, mind you, but enormous numbers. Gigantic, mind-bogglingly tremendous whoppers of numbers. Numbers that the human mind can scarcely comprehend.

    Accompanied by delightful illustrations by Isabel Greenberg, Fishman makes infinitesimal figures like the number of seconds in a year (31,536,000), the distance between the Earth and the moon (240,000 miles), and how many people go shoulder-to-shoulder every day on our big blue marble (7,500,000,000) relatable to the four-to-eight age group.

    “A child isn’t necessarily going to get the number of raindrops in a thunderstorm (1,620, 000,000,000,000),” Fishman said, “but maybe it’ll help them connect with what the word ‘trillion’ means because they know what a thunderstorm looks like.” He also throws in fun facts that pint-size readers will take delight in. Who knew that a great white shark has about 300 teeth? Or that we might eat up to 70 pounds of bugs in our lifetime? Fishman’s numbers will thrill, amaze, and elucidate.

    Read an interview with the author here.

    10. ‘Margaret and the Moon’ (Knopf Books for Young Readers, 2017)

    By Dean Robbins, Illustrated by Lucy Knisley

    Age range: 4-8

    In “Margaret and the Moon: How Margaret Hamilton Saved the First Lunar Landing,” Dean Robbins outlines the pioneering software engineer’s life, from the backyard of her childhood home, where she posed a million questions about the night sky, to the hallways of NASA, where she led a team from MIT to develop the onboard flight software that would land the first men on the moon. When an accident threatened to abort the Apollo 11 moon landing, Hamilton swooped in to save the day with her smarts and preparation. At a time when women were expected to stay in the home and raise children, Hamilton’s role in the Apollo program was “revelatory,” according to Robbins. He said he hopes his young readers will find a strong role model in Hamilton, who solved problems large and small with creativity and fearlessness. “In my wildest dreams, readers of  ‘Margaret and the Moon’ will grow up to make the next great breakthroughs in whatever they choose to do,” he said.

    Read an interview with the book’s author here.

    This roundup includes reviews from Space.com writers and contributors Jasmin Malik Chua, Calla Cofield, Nola Taylor Redd and Hanneke Weitering.

  • Winter Skywatching: Spot Some Overlooked Constellations

    The star Achernar and the constellation Eridanus.

    As we are now well into Christmas week, many neighborhoods are marking the holiday season. Streets, homes and stores are decorated in lights and festooned in evergreen, and everywhere, there’s the smiling face of jolly old Saint Nick.

    When I was a young boy growing up in the Bronx, one house in our neighborhood was transformed into a veritable twinkling wonderland in December. Its many decorations included a giant Christmas tree spangled with thousands of multicolored bulbs that almost seemed to rival the famous Rockefeller Center tree in Manhattan. 

    While such an outdoor display was quite unusual, if not unique, half a century ago, it seems that such elaborate displays are far more common today. In fact, in just the last 10 years, the practice of setting up extensive lighting displays has seemingly increased. [Holidays in Space: An Astronaut Photo Album]

    But while most visitors gravitate toward such decorated homes to gawk and take pictures, my own primary interests were with the other neighborhood homes that were either across the street or positioned (unfortunately) on either side of the dazzling light show. I always felt kind of sorry for them, because, while they were adorned with their own pretty holiday decorations, none could hope to match their local version of Times Square. 

    And this is the perfect analogy for our current evening sky, since, at this festive time of year, nature also seems to decorate the sky with bright stars. To see what I mean, just go outside this week and face southeast at around 9 p.m., and you’ll be able to see the celestial version of a house decorated with bright lights and ornaments.

    Orion, the mighty hunter

    Orion is the constellation that seemingly has everything, and everyone from astronomy neophytes to assiduous amateur astronomers is always drawn to it.

    Where else can you find two brilliant stars — ruddy Betelgeuse and blue-white Rigel — that are on diametrically opposite ends of the stellar evolution scale? Let’s also not forget the Hunter’s always-catchy three-star belt and the famous Great Nebula in his sword, known to be an incubator for new stars.

    Indeed, all of these spectacular attractions often draw attention away from some of the interesting, albeit dimmer, star patterns that just happen to be in Orion’s immediate vicinity. So, in fairness, let’s check out some of these not-as-flashy constellations, which are still quite interesting in their own right. [Constellations of the Night Sky: Famous Star Patterns Explained (Images)]

    The river of heaven

    Located due south in the sky at around 10 p.m. is the River Eridanus, a long, curving and meandering stream that shares with the Milky Way the title “River of Heaven.”

    Recently, we turned our attention to an unusually close approach to Earth of the asteroid 3200 Phaethon. Classical legend holds that Phaethon, son of the sun god Helios, fell into the River Eridanus after losing control of his father’s chariot, which carried the sun across the sky.

    Eridanus is one of the sky’s long, winding constellations, consisting of a long trail of moderate-to-faint stars. It is nonetheless fun to trace out. Its source lies immediately to the west of Rigel in Orion, with a star called Cursa. Among the river’s long stream of stars is Epsilon Eridani, one of our closest stellar neighbors at a mere 10.7 light-years away from Earth. Back in 1960, Epsilon Eridani, was monitored by Project Ozma, the first-ever effort to detect radio signals from a possible alien civilization.

    At the mouth of the river is first-magnitude Achernar, the brightest star in Eridanus. Achernar takes its name from the Arabic “Al Āhir al Nahr,” the “End of the River.” The star is positioned so far south that only those who live near or along the U.S. Gulf Coast can get a glimpse of this object as it pokes a short distance above the horizon.

    The leaping hare

    Just to the south of Orion and the west of Canis Major (the Big Dog) is a group of faint stars that seem to be arranged in the shape of a bow tie: Lepus, the Hare. Hares and jackrabbits belong to the genus Lepus. And since Orion particularly liked hunting hares, it seemed appropriate to place one below his feet in the sky. The brightest part of Lepus, composed of third- and fourth-magnitude stars, is arranged in a crude rectangle. Most of the other stars are between this group and Orion.

    Lepus’ brightest star is called Arneb, which in Arabic means “hare”; it’s a double star whose components are about third- and11th-magnitude. One interesting variable star is labeled R Leporis. It is often placed in the same class as Mira Ceti, the Wonderful Star, because it has an irregular period of roughly 432 days. The English astronomer J.R. Hind first noted R Leporis in October 1845 and described it as “resembling a blood drop on the background of the sky.” [Best Telescopes for Beginners]

    Noah’s dove

    Below Lepus, we find Columbia, a star pattern not among the original 48 constellations usually attributed to the ancients. It was created by Petrus Plancius, a 16th-century Dutch theologian and cartographer.

    In most of the older star atlases, Columbia appears as a dove holding an olive branch in its beak, apparently representing the dove that Noah sent out from the ark after the deluge had subsided, to see if the bird could find dry land — hence the pattern’s original Latin name, “Columba Noachii.” Within Columbia’s boundaries is the place from which the sun and its family of planets are receding in their swift flight toward the constellation Hercules, the “antapex of the sun’s way.”

    In 1718, astronomer Edmond Halley (of comet fame) determined that the stars were not “fixed,” but rather moved across the sky in what we call their proper motion. In our winter sky, the sun’s path in space is taking us away from Columba at about 12.4 miles (20 kilometers) per second with respect to other nearby stars.

    And a unicorn too!

    This week, after the moon has set, try to find Monoceros, the Unicorn, in the Milky Way between the dog stars Sirius and Procyon. Jakob Bartsch, Johannes Kepler’s son-in-law, is credited with identifying this star pattern in 1624, but it has been found on a Persian sphere from at least 100 years earlier. 

    Monoceros is the Latin form of a Greek word meaning “one horned,” and it seems that the mythical unicorn may have been invented as a confused description of a rhinoceros. The head of the Unicorn, or perhaps the tip of its horn, is a cloud of glowing gas popularly called “the Christmas Tree Cluster,” lying between Procyon and Betelgeuse of Orion, 2,600 light-years from Earth.

    The brightest star in this nebula, designated S Monocerotis, is a very hot variable star that’s about 214,000 times more luminous than our sun. Astronomers now recognize the youth of this sort of star; probably less than 10 million years have passed since it began to shine. Other stars clustering in this nebula may not be more than 1 million or 2 million years old. They likely are less massive than S Monocerotis and still appear to be contracting gravitationally and therefore have not yet made it to a stable star life.

    Constellations ancient and modern grace the skies year round. Let’s see what you know about the star patterns that appear overhead every night.

    Constellations of Autumn

    0 of 10 questions complete

    Would you believe a hot dog?

    Finally, there is the antithesis of a complex sky pattern, in Canis Minor, the Little Dog. Its brightest star is Procyon, the eighth-brightest star in the sky. It is a yellow-white star, six times as luminous as the sun.  Go outside this week and look low to the eastern horizon at around 8:30 p.m. and you’ll readily see it.

    The name Procyon has been in use since the days of ancient Greece. It is the equivalent of the Latin word “Antecanis” or “Before the Dog.” This is an allusion to the fact that Procyon rises immediately preceding Sirius and thus heralds the appearance of the great Dog Star.

    But there is only one other star in this constellation. Maybe instead of calling it the Little Dog, we should call it the Hot Dog?

    In fact, many years ago, in a prerecorded sky show at New York’s Hayden Planetarium, the lecturer on the tape said, “You are somehow expected to see a little dog here, using Procyon and a neighboring star.”  A voice in the dark called out, “I see it!” The next line on the tape was, “If you do see a dog here, perhaps you had better see a doctor, too.” 

    The lecturer’s next few lines were hard to hear over the laughter of the audience.

    Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmer’s Almanac and other publications, and he is also an on-camera meteorologist for Verizon Fios1 News, based in Rye Brook, N.Y. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

  • NASA Astronauts Share Christmas Memories from Space (Video)

    Two NASA astronauts aboard the International Space Station (ISS) share some of their favorite Christmas memories in a new holiday video.

    Expedition 54 flight engineer Joe Acaba recalled a family trip to the Turks and Caicos Islands, a British territory in the Caribbean, for a special tropical Christmas.

    “We were celebrating my sister-in-law’s 5-year battle against cancer,” Acaba said in the 90-second video, which NASA posted on YouTube Wednesday (Dec. 20). “She’s doing great. There’s nothing better than having the family together, celebrating it together. We love you, Liz!” [Holidays in Space: An Astronaut Photo Album]

    Fellow Expedition 54 flight engineer Mark Vande Hei remembered coming downstairs on Christmas morning as a child and being overwhelmed by the number of presents waiting to be opened.

    “It looked to me like the whole floor that the Christmas tree was on was full of gifts,” Vande Hei said. “That gave me proof that Santa Claus was real, so I almost got in some fights at school, because people were trying to convince me that Santa Claus wasn’t real.”

    As far as favorite Christmas gifts go, Acaba cited a treasured BMX bike, sounding very much like the Southern California kid that he once was: “We would be out, riding through the orange groves, and just having a great time. It was totally cool.”

    Vande Hei, by contrast, singled out something that kept him inside for long stretches. 

    “Gosh, my mom’s going to be disappointed in me for saying this,” he said. “When we got an Atari, I spent way too many hours playing on that thing.” 

    Six spaceflyers will spend the holidays aboard the orbiting lab this year. In addition to Acaba and Vande Hei, they are NASA astronaut Scott Tingle, Japan Aerospace Exploration Agency astronaut Norishige Kanai, and cosmonauts Anton Shkaplerov and Alexander Misurkin (who commands Expedition 54).

    ISS crewmembers’ schedules are pretty packed, but this group will definitely celebrate the season, as spaceflyers have for 17 straight years. (The station has been continuously staffed by rotating crews since November 2000.)

    “We [already] have a Christmas tree aboard, and there is a new Christmas tree arriving soon,” Shkaplerov told reporters Saturday (Dec. 16), one day before he, Tingle and Kanai launched toward the ISS from Baikonur Cosmodrome in Kazakhstan. The trio arrived at the station on Tuesday (Dec. 19).

    “We have packages and gifts from our families and friends, and packages on board the ISS labeled to open on Dec. 25 for U.S. crewmembers and Dec. 31 for us from Russia,” Shkaplerov added.

    Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

  • SpaceX, Japan Launching Satellites Back to Back Tonight: Watch Live

    Update for 10 p.m. ET: SpaceX has successfully launched the 10-satellite Iridium-4 mission in a spectacular evening launch. See our launch wrap story with video and photos here: Used SpaceX Rocket Launches 10 Communications Satellites Once Again

    Two rockets are scheduled to launch within 1 minute of each other tonight (Dec. 22), and you can catch the back-to-back spaceflight action live.  

    A Japanese H-2A rocket will lead things off with a liftoff from Tanegashima Space Center at 8:26 p.m. EST Friday (0126 GMT; 1:26 a.m. local Japan time on Dec. 23). One minute later, a two-stage SpaceX Falcon 9 rocket with a pre-flown first stage is scheduled to rise from California’s Vandenberg Air Force Base.

    You can watch both launches live here at Space.com, courtesy of the Japan Aerospace Exploration Agency (JAXA) and SpaceX, respectively.

    The Falcon 9 will carry aloft 10 communications satellites for the Iridium Next commercial constellation, marking the second such mission for the rocket’s first stage: That booster was part of the Falcon 9 that launched 10 Iridium Next satellites this past June. 

    The communications company Iridium is therefore poised to become the first SpaceX customer ever to fly multiple missions with the same Falcon 9 first stage.

    Today’s liftoff will be the last one for this particular first stage, however: SpaceX does not plan to bring it down for a landing, company representatives have said.

    To date, SpaceX has landed first stages 20 times during Falcon 9 launches and has reflown four of these landed boosters.

    The H-2A, meanwhile, is topped with two JAXA payloads — the Global Change Observation Mission-Climate (GCOM-C) satellite and the Super Low Altitude Test Satellite (SLATS). GCOM-C will monitor global water circulation and climate change from orbit for at least 10 years; and SLATS will test an efficient ion-engine technology developed to help satellites operate at altitudes below 190 miles (300 kilometers), where air resistance is significant, JAXA officials said.

    Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

  • The Fate of the Voyagers

    NASA’s Voyager spacecraft are humanity’s most distant emissaries.

    Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI science center. Sutter is also host of “Ask a Spaceman” and “Space Radio,” and leads AstroTours around the world. Sutter contributed this article to Space.com’s Expert Voices: Op-Ed & Insights.

    It must be lonely traveling out beyond the edge of the solar system — at points so distant that the sun is just another point of light — still brilliant, but without shape. And as the years go by and the kilometers add up, the sun, too, fades into the background, just one of the multitude of stars in our galaxy.

    It’s almost inconceivable: two small spacecraft, each no bigger than a car, furnished here on Earth and flung into the depths. Their missions nearly over, their power supplies almost exhausted. Their ultimate fates to wander the vast expanses of the Milky Way. Alone.

    The Voyager missions, launched in the late 1970s, are now the furthest-flung emissaries of humanity. Here is a recounting of their travels so far, and what the future has in store for them. [5 Facts About NASA’s Far-Flung Voyager Spacecraft]

    A one-way trip

    It was perfectly timed. Just a couple decades after we first developed the technology to launch interplanetary space probes, equip them with cameras and other scientific instruments, and remotely communicate with them, the planets aligned. Usually, that phrase is relegated to meaningless astrological positions, but this time it meant something seriously scientific.

    About every 200 years, the outer planets of our solar system — Jupiter, Saturn, Uranus and Neptune — wind up on the same side of the sun, making it possible for a single swift spacecraft to visit all of them in one go. That’s important, because when something is launched to the edge of the solar system at tens of thousands of miles per hour, it’s not exactly going to come back home.

    The alignment occurred most recently in the 1970s and ’80s, enabling the breakthrough Voyager missions. The twin spacecraft (ah, those were the days, when NASA could build two of everything) were packed with the latest observational gear, far surpassing the capabilities of the earlier Pioneer probes. 

    The scientific return from those two craft is almost immeasurable. Detailed images of the cloud tops of Jupiter. Analyses of the rings of Saturn. Magnetic field measurements; cosmic ray detections. An unprecedented close-up view of the giants of our solar system.

    Over the edge

    After 1989, the Voyager probes’ primary mission was over. The most distant of the siblings, Voyager 1, now sits 13 billion miles (21 billion km) from the sun. That’s 140 times greater than the Earth-sun distance, for those of you keeping score.

    On Aug. 25, 2012, Voyager 1 reached a new milestone: It became the first human-made object to truly exit the solar system. While there are a few definitions of the boundary to interstellar space, the one used by NASA makes enough sense: the hazy bubble layer where the high-energy particles emitted by the sun (the “solar wind”) mix and mingle with the general galactic milieu. 

    [embedded content]

    After that momentous event, Voyager 1 is now adrift between the stars. Light-years of essentially nothing between it and … well, nothing else. In about 300 years, the craft will reach the inner boundary of the Oort Cloud, the thin, diffuse shell of frozen debris left over from the formation of the solar system.

    Voyager 1 will eventually come within 1.6 light-years of the star Gliese 445 — in astronomical terms, this will be a near-miss. But don’t hold your breath; the “encounter,” for lack of a better term, won’t occur for another 40,000 years.

    After that, it gets a little difficult to predict Voyager’s journey, as chaotic motions within the galaxy make accurate predictions of stellar movements challenging. But given the wide swaths of empty space between the stars, the spacecraft’s visit near Gilese 445 is probably the closest that Voyager 1 will approach another star, ever. 

    In 200 million years, the lonely spacecraft will complete its first circumnavigation of our galaxy.

    The song of our people

    The Voyager spacecraft carry more than just scientific instruments, which will be rendered useless in a few more years. (Their radioisotope thermoelectric generators, powered by piles of radioactive plutonium, will soon exhaust themselves.)

    Tucked between those instruments, bolted to the exterior of each spacecraft, is a small golden disk. Etched into that disk are diagrams showing the location of the sun relative to nearby known, flashing, dense cores of stars called pulsars; representations of the hydrogen atom; and instructions. 

    Following the pictograms, one could — it’s hoped — construct a spinning platform and a stylus, spinning the disc to interpret the vibrations in the stylus as sound waves. (That is, an alien could play the record.) [Dear E.T.: Math on Voyager’s Golden Record Tells a Story]

    [embedded content]

    Those sound waves carry raw information, but also recordings of sounds from here on Earth: voices, nature and music from around the world. The record was designed by a committee led by Carl Sagan, a scientist and legendary science communicator, and Frank Drake, an astronomer whose famous equation purports to estimate the odds of finding extraterrestrial life. The record is intended to be an everlasting emissary of Earth, a thin slice of what humanity is.

    For sure, this Golden Record will outlive its creators, and maybe even us as a species. It’s a bold and noble effort.

    But it’s doomed to fail, except as a symbol. Interstellar space is just that: space. There’s an incredible amount of open room between the denizens of our galaxy. Heck, even 1.6 light-years is considered a brief stroll in these contexts. Add to that the extreme rarity of life, and the Voyager probes are almost certainly fated to touch nothing but microscopic interstellar dust for billions of years, or even for eternity.

    So bold and noble, but also futile and narcissistic. Perhaps it does reflect our species after all…

    Learn more by listening to the episode “What Fate Awaits the Voyagers?” on the “Ask a Spaceman” podcast, available on iTunes and on the web at http://www.askaspaceman.com. Thanks to Rob H. and Ryan S. for the questions that led to this piece! Ask your own question on Twitter using #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

  • 2018 Moon Phases Calendar

    Some nights when we look up at the moon, it is full and bright; sometimes it is just a sliver of silvery light. These changes in appearance are the phases of the moon. As the moon orbits Earth, it cycles through eight distinct phases. The four primary phases occur about a week apart.

    Lunar calendar for 2018

    Here are the dates of the moon’s phases for 2018, according to NASA. Times and dates are in Eastern U.S. time.

    1st Qtr Full Moon Last Qtr New Moon
        Jan 1 21:24 Jan 8 17:25 Jan 16 21:17
    Jan 24 17:20 Jan 31 08:27 Feb 7 10:54 Feb 15 16:05
    Feb 23 03:09 Mar 1 19:51 Mar 9 06:20 Mar 17 09:12
    Mar 24 11:35 Mar 31 08:37 Apr 8 03:18 Apr 15 21:57
    Apr 22 13:49 Apr 29 20:58 May 7 22:09 May 15 07:48
    May 21 23:49 May 29 10:20 Jun 6 14:32 Jun 13 15:43
    Jun 20 06:51 Jun 28 00:53 Jul 6 03:51 Jul 12 22:48
    Jul 19 15:52 Jul 27 16:21 Aug 4 14:18 Aug 11 05:58
    Aug 18 03:49 Aug 26 07:56 Sep 2 22:37 Sep 9 14:01
    Sep 16 19:15 Sep 24 22:53 Oct 2 05:45 Oct 8 23:47
    Oct 16 14:02 Oct 24 12:45 Oct 31 11:40 Nov 7 11:02
    Nov 15 09:54 Nov 23 00:39 Nov 29 19:19 Dec 7 02:20
    Dec 15 06:20 Dec 22 12:49 Dec 29 04:34    

    Phases of the moon

    The moon, like Earth, is a sphere, and it is always half-illuminated by the sun. However, as the moon travels around Earth, we see more or less of the illuminated half. The moon’s phases describe how much of the moon’s disk is illuminated from our perspective.

    New moon: The moon is between Earth and the sun, and the side of the moon facing toward us receives no direct sunlight; it is lit only by dim sunlight reflected from Earth.

    Waxing crescent: As the moon moves around Earth, the side we can see gradually becomes more illuminated by direct sunlight.

    First quarter: The moon is 90 degrees away from the sun in the sky and is half-illuminated from our point of view. We call it “first quarter” because the moon has traveled about a quarter of the way around Earth since the new moon.

    See the moon phases, and the difference between a waxing and waning crescent or gibbous moon, in this Space.com infographic about the lunar cycle each month. <a href=See the full infographic. ” data-options-closecontrol=”true” data-options-fullsize=”true”/>
    See the moon phases, and the difference between a waxing and waning crescent or gibbous moon, in this Space.com infographic about the lunar cycle each month. See the full infographic.

    Credit: Karl Tate, SPACE.com

    Waxing gibbous: The area of illumination continues to increase. More than half of the moon’s face appears to be getting sunlight.

    Full moon: The moon is 180 degrees away from the sun and is as close as it can be to being fully illuminated by the sun from our perspective. The sun, Earth and the moon are aligned, but because the moon’s orbit is not exactly in the same plane as Earth’s orbit around the sun, they rarely form a perfect line. When they do, we have a lunar eclipse as Earth’s shadow crosses the moon’s face.

    Waning gibbous: More than half of the moon’s face appears to be getting sunlight, but the amount is decreasing.

    Last quarter: The moon has moved another quarter of the way around Earth, to the third quarter position. The sun’s light is now shining on the other half of the visible face of the moon.

    Waning crescent: Less than half of the moon’s face appears to be getting sunlight, and the amount is decreasing.

    Finally, the moon is back to its new moon starting position. Now, the moon is between Earth and the sun. Usually the moon passes above or below the sun from our vantage point, but occasionally it passes right in front of the sun, and we get a solar eclipse. [Infographic: How Moon Phases Work]

    Additional resources

  • Space Industry Takes Prominent Role in Trump's National Security Strategy

    President Donald Trump discusses space policy at the White House Dec. 11, 2017.

    WASHINGTON — The Trump administration is elevating the role of the privately funded space industry in advancing the nation’s interests as competitors like Russia and China seek to challenge the United States and its free rein in space.

    In the 2017 National Security Strategy released Dec. 18, the president commits the U.S. government to partnering with private industry to explore space and defend U.S. assets there. The administration also promises to help defend private space systems from hostile attacks.

    The strategy makes the promotion of space commerce a national security priority. In that vein, the administration intends to overhaul industry regulations to motivate companies to invest and innovate. “The United States will simplify and update regulations for commercial space activity to strengthen competitiveness,” says the document. [From Ike to Trump: Presidential Visions for Space Exploration]

    The U.S. government and the private sector will advance human exploration across the solar system to “bring back to Earth new knowledge and opportunities,” says the strategy. The administration will pursue public-private partnerships and promote ventures beyond low Earth orbit.

    Further, the government will team up with commercial firms to “improve the resiliency of our space architecture. … We will also consider extending national security protections to our private sector partners as needed.”

    “The United States must maintain our leadership and freedom of action in space,” says the strategy.

    Protecting U.S. access to space is an imperative because so much economic and national security activities depend on it. “Communications and financial networks, military and intelligence systems, weather monitoring, navigation, and more have components in the space domain,” says the document. “As U.S. dependence on space has increased, other actors have gained access to space-based systems and information.”

    The “democratization of space” means many governments and nonstate actors can launch satellites into space at relatively low cost. And they can exploit the technology in ways that could be detrimental to the United States, the strategy cautions. “The fusion of data from imagery, communications, and geolocation services allows motivated actors to access previously unavailable information.”

    U.S. rivals are perfecting technologies and tactics to hack U.S. space assets, and that will require new approaches to deal with space as a contested battlefield. “Any harmful interference with or an attack upon critical components of our space architecture that directly affects this vital U.S. interest will be met with a deliberate response at a time, place, manner, and domain of our choosing.”

    The strategy casts China and Russia as sly, stealthy rivals that quietly are working to undermine U.S. advantages. “They are patient and content to accrue strategic gains over time — making it harder for the United States and our allies to respond,” says the strategy. “Such actions are calculated to achieve maximum effect without provoking a direct military response from the United States.”

    The United States “must prepare for this type of competition” in which space is just one piece of the puzzle. Adversaries assume the United States views the world in binary terms, with states being either “at peace” or “at war,” when it is actually an arena of continuous competition. “Our diplomatic, intelligence, military, and economic agencies have not kept pace with the changes in the character of competition.”

    The responsibility to advance these policies will fall on the National Space Council, chaired by Vice President Mike Pence. The council will “review America’s long-range space goals and develop a strategy that integrates all space sectors to support innovation and American leadership in space.”

    Scott Pace, executive secretary of the National Space Council, echoed the themes of the president’s strategy last week in a speech to a space law group in Washington, D.C.

    “The United States should strive to be the most attractive jurisdiction in the world for private sector investment and innovation in outer space,” Pace said. “This requires a transparent, efficient, and minimally burdensome domestic regulatory mechanism for U.S. companies conducting space activities.”

    The U.S. government and the private sector, he said, “should use legal and diplomatic means to create a stable, peaceful environment not only for governmental activities, but also for commercial ones.” This will require efforts to “minimize and mitigate harmful interference to our space systems, whether from terrestrial actors or from space actors.”

    The American private sector, Pace said, “must have confidence that it will be able to profit from capital investments” in space systems and infrastructure.

    This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.

  • How to Temporarily Undo the Universe's Endless Chaos with Chloroform

    Things spread out. They cool down, disintegrate and die. Disorder is going to kill the universe. Chaos increases. It’s everywhere, and it’s growing. Scientists know this.

    And yet, researchers have now demonstrated that there are certain circumstances in which disorder is beat back briefly. In a paper published Nov. 9 on the online preprint journal arXiv, researchers showed that heat could briefly flow from a cold atom to a hot one inside a chloroform molecule, locally reversing the normal flow of the universe.

    What does it mean for disorder to govern everything?

    Stir milk into coffee, and the brown mixture will never separate on its own back into its constituent fluids. Build a sandcastle on the beach, and within an hour or two, it’ll disappear under the waves. Live a long life, and eventually the body’s precisely ordered internal systems will fail.

    This constant increase in entropy, or tendency for ordered things to become disordered, isn’t just a habit of the universe — it’s one of the known world’s fundamental rules, enshrined as the second law of thermodynamics. One of the most basic demonstrations of the ruling disorder involves heat. Drop an ice cube into boiling water, and the speck of heat in the cube won’t add to the water’s heat. Instead, heat will flow from the hot water into the cool ice. The ice will melt, and the water will cool down. [Twisted Physics: 7 Mind-Blowing Findings]

    Of course, order can be built from disorder. Air conditioners cool down an apartment on a hot day. Chunks of silicone, aluminum and loose sand emerged from mines and were transformed into the microchip, device chassis and screen used to read this article. Oil bubbles in the hot baths of the early Earth gave rise to the full spectacle of organic life.

    But in each of these so-called open systems, some external source of energy made that local act of organization happen. A pump drew power from an electric plant to push hot air outside, humans mushed up food into bodily fuel which they used to haul resources out of mines and reshape them, the sun bathed the planet in life-giving heat as it slowly burned through its fuel reserves, which will one day run out and dissipate. View the so-called closed system in its totality, with no energy being pumped in, and the trend is still toward disorganization.

    Breaking entropy?

    But are there any cases in which this isn’t true? The short answer: When the initial conditions of the closed system are weird — quantum-mechanically weird — then the situation can be reversed.

    The complete answer: When two atomic nuclei inside a chloroform molecule have the same spin, but different temperatures, heat can flow from the colder nucleus to the hotter nucleus.

    Spin is a quantum mechanical feature of atomic particles, measured in multiples of one-half. Two particles in a system can be correlated, meaning they share physical information — a narrower version of the effect that occurs during quantum entanglement — by aligning their spins.

    In the new study’s experimental setup, researchers observed two kinds of chloroform, a molecule made up of one carbon nucleus linked to a hydrogen nucleus and three chlorine nuclei. The researchers used a technique called nuclear magnetic resonance.

    The first chloroform sample had hydrogen and carbon atoms with uncorrelated spins, but the hydrogen was hotter than the carbon. Over a very short time, heat flowed from the hydrogen to the carbon, as predicted by thermodynamics.

    But when the hydrogen and carbon spins were correlated, heat flowed in the opposite direction — from the cool carbon into the hot hydrogen. In effect, the researchers wrote, they “reversed the arrow of time,” creating a closed system in which entropy spontaneously decreases.

    A figure from the paper shows the differences in energy flow.

    A figure from the paper shows the differences in energy flow.

    Credit: arXiv

    “We observe a spontaneous heat current from the cold to the hot spin,” the authors wrote, “and show that this process is made possible by a decrease of the mutual information between the spins.”

    In other words, the heat flows against the normal current of entropy, but the correlation between the atoms that makes that paradoxical flow possible breaks down as the reverse flow happens.

    Does this violate the second law of thermodynamics?

    The counterintuitive heat flow in this experiment does violate the second law as it’s classically stated: Heat always flows from a hot place to a cool place, according to that formulation.

    But scientists have known for a long time that the world is more complicated than that. A more complete statement of the second law goes like this: The known universe is so well-ordered, it’s overwhelmingly likely to tend toward disorder. When a bright, massive sun is shining in a dark void, the universe is very uneven,. That difference in energy and mass is a sign that something unusual is going on — an imbalance has appeared that the second law will seek to flatten out.

    In other words, the universe is already so low in disorder that the tendency is toward more disorder, but a system without that precondition wouldn’t necessarily tend toward entropy. A 2008 arXiv paper examining how quantum correlations complicate entropy quotes the 19th-century physicist Ludwig Boltzmann, who stated that “the universe, considered as a mechanical system … started from a very improbable state, and is still in a very improbable state.”

    But the relationship between two correlated atoms isn’t a typical feature of that “improbable,” low-entropy environment, those 2008 researchers wrote, and operates according to an unusual set of rules without violating the second law. Those rules are temporary by nature, though. As this recent experiment demonstrates, the correlation that makes the reverse heat transfer possible is destroyed by that transfer even as it happens.

    “The arrow of time,” the researchers wrote, meaning the normal, one-directional flow of entropy, “is not an absolute but a relative concept that depends on the choice of initial conditions.”

    And with this more nuanced understanding of the second law intact, the universe still tends toward chaos. The correlations between particles are temporary, the experimentalists wrote, and dissipate within milliseconds even as they enable these unusual heat flows. This way, the heat death of the universe still comes.

    Originally published on Live Science.

  • What is Astrophysics?

    The Hubble mosaic unveils a collection of carved knots of gas and dust in a small portion of the Monkey Head Nebula (also known as NGC 2174 and Sharpless Sh2-252). The nebula is a star-forming region that hosts dusky dust clouds silhouetted against glowing gas.

    Astrophysics is a branch of space science that applies the laws of physics and chemistry to explain the birth, life and death of stars, planets, galaxies, nebulae and other objects in the universe. It has two sibling sciences, astronomy and cosmology, and the lines between them blur. 

    In the most rigid sense:

    • Astronomy measures positions, luminosities, motions and other characteristics
    • Astrophysics creates physical theories of small to medium-size structures in the universe
    • Cosmology does this for the largest structures, and the universe as a whole. 

    In practice, the three professions form a tight-knit family. Ask for the position of a nebula or what kind of light it emits, and the astronomer might answer first. Ask what the nebula is made of and how it formed and the astrophysicist will pipe up. Ask how the data fit with the formation of the universe, and the cosmologist would probably jump in. But watch out — for any of these questions, two or three may start talking at once!

    Goals of astrophysics

    Astrophysicists seek to understand the universe and our place in it. At NASA, the goals of astrophysics are “to discover how the universe works, explore how it began and evolved, and search for life on planets around other stars,” according NASA’s website.

    NASA states that those goals produce three broad questions:

    • How does the universe work?
    • How did we get here?
    • Are we alone?

    It began with Newton

    While astronomy is one of the oldest sciences, theoretical astrophysics began with Isaac Newton. Prior to Newton, astronomers described the motions of heavenly bodies using complex mathematical models without a physical basis. Newton showed that a single theory simultaneously explains the orbits of moons and planets in space and the trajectory of a cannonball on Earth. This added to the body of evidence for the (then) startling conclusion that the heavens and Earth are subject to the same physical laws.

    Perhaps what most completely separated Newton’s model from previous ones is that it is predictive as well as descriptive. Based on aberrations in the orbit of Uranus, astronomers predicted the position of a new planet, which was then observed and named Neptune. Being predictive as well as descriptive is the sign of a mature science, and astrophysics is in this category.

    Milestones in astrophysics

    Because the only way we interact with distant objects is by observing the radiation they emit, much of astrophysics has to do with deducing theories that explain the mechanisms that produce this radiation, and provide ideas for how to extract the most information from it. The first ideas about the nature of stars emerged in the mid-19th century from the blossoming science of spectral analysis, which means observing the specific frequencies of light that particular substances absorb and emit when heated. Spectral analysis remains essential to the triumvirate of space sciences, both guiding and testing new theories.

    Early spectroscopy provided the first evidence that stars contain substances also present on Earth. Spectroscopy revealed that some nebulae are purely gaseous, while some contain stars. This later helped cement the idea that some nebulae were not nebulae at all — they were other galaxies! 

    In the early 1920s, Cecilia Payne discovered, using spectroscopy, that stars are predominantly hydrogen (at least until their old age). The spectra of stars also allowed astrophysicists to determine the speed at which they move toward or away from Earth. Just like the sound a vehicle emits is different moving toward us or away from us, because of the Doppler shift, the spectra of stars will change in the same way. In the 1930s, by combining the Doppler shift and Einstein’s theory of general relativity, Edwin Hubble provided solid evidence that the universe is expanding. This is also predicted by Einstein’s theory, and together form the basis of the Big Bang Theory.

    Also in the mid-19th century, the physicists Lord Kelvin (William Thomson) and Gustav Von Helmholtz speculated that gravitational collapse could power the sun, but eventually realized that energy produced this way would only last 100,000 years. Fifty years later, Einstein’s famous E=mc2 equation gave astrophysicists the first clue to what the true source of energy might be (although it turns out that gravitational collapse does play an important role). As nuclear physics, quantum mechanics and particle physics grew in the first half of the 20th century, it became possible to formulate theories for how nuclear fusion could power stars. These theories describe how stars form, live and die, and successfully explain the observed distribution of types of stars, their spectra, luminosities, ages and other features.

    Astrophysics is the physics of stars and other distant bodies in the universe, but it also hits close to home. According to the Big Bang Theory, the first stars were almost entirely hydrogen. The nuclear fusion process that energizes them smashes together hydrogen atoms to form the heavier element helium. In 1957, the husband-and-wife astronomer team of Geoffrey and Margaret Burbidge, along with physicists William Alfred Fowler and Fred Hoyle, showed how, as stars age, they produce heavier and heavier elements, which they pass on to later generations of stars in ever-greater quantities. It is only in the final stages of the lives of more recent stars that the elements making up the Earth, such as iron (32.1 percent), oxygen (30.1 percent), silicon (15.1 percent), are produced. Another of these elements is carbon, which together with oxygen, make up the bulk of the mass of all living things, including us. Thus, astrophysics tells us that, while we are not all stars, we are all stardust.

    Astrophysics as a career

    Becoming an astrophysicist requires years of observation, training and work. But you can start becoming involved in a small way even in elementary and high school, by joining astronomy clubs, attending local astronomy events, taking free online courses in astronomy and astrophysics, and keeping up with news in the field on a website such as Space.com. 

    In college, students should aim to (eventually) complete a doctorate in astrophysics, and then take on a post-doctoral position in astrophysics. Astrophysicists can work for the government, university labs and, occasionally, private organizations.

    Study.com further recommends the following steps to put you on the path to being an astrophysicist:

    Take math and science classes all through high school. Make sure to take a wide variety of science classes. Astronomy and astrophysics often blend elements of biology, chemistry and other sciences to better understand phenomena in the universe. Also keep an eye out for any summer jobs or internships in math or science. Even volunteer work can help bolster your resume.

    Pursue a math- or science-related bachelor’s degree. While a bachelor in astrophysics is the ideal, there are many other paths to that field. You can do undergraduate study in computer science, for example, which is important to help you analyze data. It’s best to speak to your high school guidance counselor or local university to find out what degree programs will help you.

    Take on research opportunities. Many universities have labs in which students participate in discoveries — and sometimes even get published. Agencies such as NASA also offer internships from time to time. 

    Finish a doctorate in astrophysics. A Ph.D. is a long haul, but the U.S. Bureau of Labor Statistics points out that most astrophysicists do have a doctoral degree. Make sure to include courses in astronomy, computer science, mathematics, physics and statistics to have a wide base of knowledge.

    Natalie Hinkel, a planetary astrophysicist who was then at Arizona State University, gave a lengthy interview with Lifehacker in 2015 that provided a glimpse into the rewards and challenges of being a junior astrophysics researcher. She described the long number of years she has put into doing her research, the frequent job switches, her work hours and what it’s like to be a woman in a competitive field. She also had an interesting insight about what she actually did day to day. Very little of her time is spent at the telescope.

    “I spend the vast majority of my time programming. Most people assume that astronomers spend all of their time at telescopes, but that’s only a very small fraction of the job, if at all. I do some observations, but in the past few years I’ve only been observing twice for a total of about two weeks,” Hinkel told Lifehacker. 

    “Once you get the data, you have to reduce it (i.e. take out the bad parts and process it for real information), usually combine it with other data in order to see the whole picture, and then write a paper about your findings. Since each observation run typically yields data from multiple stars, you don’t need to spend all of your time at the telescope to have enough work.”

    Additional reporting by Elizabeth Howell, Space.com contributor. 

    Additional resources

  • Winter Solstice: The Science of the Shortest Day of 2017

    On the winter solstice, the sun is at its southernmost point in the sky in the Northern Hemisphere.

    The winter solstice is in full stride today (Dec. 21), which boasts the fewest hours of daylight for 2017 in the Northern Hemisphere.

    Although the solstice gets an entire day of recognition, it happens in an instant: at 11:28 a.m. EST (16:28 GMT), when the North Pole is at its farthest tilt of 23.5 degrees away from the sun. This position leaves the North Pole beyond the sun’s reach, and plunges it into total darkness, according to EarthSky.org.

    In the Southern Hemisphere, the sun will shine directly overhead at Noon at exactly 23.5 degrees south of the equator, along the imaginary latitude line known as the Tropic of Capricorn, which runs through Australia, Chile, southern Brazil and northern South Africa. This is when when the sun appears to be at its southernmost point in the sky; as such, the Southern Hemisphere has its longest day of the year, and the Northern Hemisphere has its shortest day of the year, on the December solstice, according to EarthSky. [6 Ancient Tributes to the Winter Solstice]

    At the moment of the solstice, the sun will also reach its southernmost point in the sky in the Northern Hemisphere. After that moment, the sun will stop moving southward and will begin its trek northward in the sky — hence the name “solstice,” which means “sun stands still” in Latin, according to NASA.

    After the winter solstice, the days will begin to get longer in the Northern Hemisphere. But that doesn’t mean temperatures will increase immediately. Rather, northern midlatitudes will experience the winter chill partly because they’ll get about 9 hours of daylight in the weeks following the solstice, compared with the roughly 15 hours of daily sunlight they get around the summer solstice, Live Science reported in 2012. In addition, the Northern Hemisphere is tilted away from the sun, making it colder.

    In addition, even as the days get longer, the oceans, which moderate temperatures on land, need a vast amount of energy from the sun to heat up.

    There are countless cultures that have recognized the winter solstice. The most famous is in Stonehenge in England. When the sun sets on the shortest day of the year, the sun’s rays align with Stonehenge’s central Altar stone and Slaughter stone, which may have had spiritual significance to the people who built the monument, Live Science reported in 2013.

    Across the world in Mexico’s Yucatan Peninsula, the ancient stonewalled Mayan city of Tulum also has a structure honoring the solstices. When the sun rises on the winter and summer solstices, its rays shine through a small hole at the top of one of the stone buildings, which creates a starburst effect.

    Editor’s note: This article was originally published Dec. 21, 2016. It was updated on Dec. 21, 2017. 

    Original article on Live Science.

  • 2017's Dim Ursid Meteor Shower Peaks Now, Lucks Out with Darkened Sky

    When skywatchers think of meteor showers during the month of December, they immediately think of the Geminids, which has evolved over the years into the most prolific and reliable of the dozen or so annual meteor displays. But there is another notable meteor shower in December that, in contrast, hardly gets any notice: the December Ursids.

    The peak of this meteor display usually occurs during the overnight hours of Dec. 21-22.

    The Ursids gain their name from the constellation of Ursa Minor, the Little Bear. They appear to fan out from the location of the bright orange star Kochab, also located Ursa Minor. Kochab is the brighter of the two outer stars in the bowl of the Little Dipper (the other being Pherkad) that seem to march in a circle like sentries around Polaris, the North Star. Some call these meteors the Umids, in a rather unsuccessful attempt to make clear that their radiant is in Ursa Minor, not Ursa Major. [Ursid Meteor Shower 2017: When, Where & How to See It ]

    The 2017 Ursid meteor shower peaks during the overnight hours of Dec. 21-22 and radiates out from the constellation Ursa Minor, as shown in this NASA sky map. But dark skies are needed to see the display's 10 meteors per hour.

    The 2017 Ursid meteor shower peaks during the overnight hours of Dec. 21-22 and radiates out from the constellation Ursa Minor, as shown in this NASA sky map. But dark skies are needed to see the display’s 10 meteors per hour.

    Credit: NASA/JPL-Caltech

    Often neglected

    Because Kochab is so close to the North Pole of the sky, this star almost never sets for most viewers in the Northern Hemisphere. And since the Ursids seem to fan out from this region of the sky (making it the radiant for the Umid shower), you can look for these faint, medium-speed meteors all through the night. This year, you should have a good shot at spotting some: The moon is new on Dec. 18, assuring dark skies.

    These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. On the morning of maximum, from five to 10 Ursids may be seen per hour. Plunging through the Earth’s atmosphere at 22 miles (35 kilometers) per second, the Ursids consist of mostly medium-speed meteors. Very little activity will be seen outside the night of maximum activity.

    This is indeed fortunate, because the Ursids “badly need observing,” said the British Astronomical Association.

    Indeed, the Ursids are a very poorly observed Northern Hemisphere shower, which has nonetheless produced at least two major outbursts in the past 70 years, in 1945 and 1986. Some other outbursts could have been missed due to weather conditions. Several lesser rate-enhancements were also reported from 2006 to 2008; those might have been influenced by the relative proximity of the shower’s parent comet, 8P/Tuttle, which circles the sun in a 13.6-year orbit and most recently swept past the sun in January 2008.

    And for some still-unexplained reason, many Ursid peaks have occurred when Comet Tuttle was not sweeping through the inner solar system, but rather at the far end of its orbit (aphelion), as far away from the sun as the comet can get. Slightly enhanced rates were found in video data in 2014 and 2015, as well, indicating the difficulty of trying to forecast what this meteor swarm might do in a given year. [Best Night Sky Events of December 2017 (Stargazing Maps)] 

    Meteor showers can be awesome night sky sights, but how well do you know your shooting star facts? Find out here and good luck!

    False-color image of a rare early Quadrantid, captured by a NASA meteor camera in 2010.

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    Enhanced activity?

    No unusually strong activity has been forecasted for the 2017 shower. Computer simulations by the French astronomer Jérémie Vaubaillon do suggest that on Friday (Dec. 22) at 9:43 p.m. EDT (1443 GMT), Earth will approach a dust trail ejected by comet Tuttle back in 884. But unfortunately, most of North America will be in daylight when Earth is closest to this dusty trail of comet debris.

    Still, if you’re up before dawn breaks that morning, and if your skies are clear, you might want to step outside and check the northern sky. December’s new moon gives a perfect chance to end the year on a positive note, if skies are clear enough to see what the Ursids do this time.

    Editor’s note: If you snap an amazing Ursid meteor shower photo that you’d like to share with us and our news partners for a possible story or image gallery, send images and comments to us at: spacephotos@space.com.

    Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmer’s Almanac and other publications, and he is also an on-camera meteorologist for Verizon Fios1 News, based in Rye Brook, New York.Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.