Author: jappe

This radio image shows a shock wave (the bright arc running from bottom left to top right) in the ‘Sausage’ merging cluster of galaxies as seen by the Giant Metrewave Radio Telescope. The shock wave was generated 1 billion years ago, when the two original clusters collided, and is moving at 5.6 million mph (9 million km/h). Credit: Andra Stroe

A so-called “cosmic tsunami” is rousing a galaxy cluster affectionately nicknamed “Sausage,” suggesting that stagnant galaxies can be rejuvenated when galactic clusters collide, scientists say.

Astronomers made the discovery while studying CIZA J2242.8+5301, an ancient galaxy cluster 2.3 billion light-years from Earth. The cluster (yes, they actually call it Sausage), which is full of old red stars, is waking up as a shock wave triggers new star formation. The shock wave from the cluster’s collision, which scientists compared to a tsunami, began 1 billion years ago and is moving at a mind-boggling speed: 5.6 million mph (9 million km/h).

“We assumed that the galaxies would be on the sidelines for this act, but it turns out they have a leading role,” study co-leader Andra Stroe, an astronomer at Leiden Observatory, said in a statement. “The comatose galaxies in the Sausage cluster are coming back to life, with stars forming at a tremendous rate. When we first saw this in the data, we simply couldn’t believe what it was telling us.” [Epic Photos: When Galaxies Collide]

This is the first time such star formation has been observed, but in theory nearly every galaxy cluster should have passed through this period of furious star formation. Alas, such a resurrection is not meant to last, the researchers said.

“But star formation at this rate leads to a lot of massive, short-lived stars coming into being, which explode as supernovae a few million years later,” the study’s other co-leader, David Sobral of Leiden and the University of Lisbon, said in a statement. “The explosions drive huge amounts of gas out of the galaxies and with most of the rest consumed in star formation, the galaxies soon run out of fuel. If you wait long enough, the cluster mergers make the galaxies even more red and dead — they slip back into a coma and have little prospect of a second resurrection.”

This composite image of the ‘Sausage’ merging galaxy cluster CIZA J2242.8+5310 was made using data from the Subaru and Canada France Hawaii Telescopes (CFHT). The white circles indicate galaxies outside of the cluster, while yellow circles are cluster galaxies, where accelerated star formation is taking place. Green hues trace out shock waves and purple marks hot X-ray-emitting gas between the galaxies that emits X-rays.
Credit: Andra Stroe

Stroe, Sobal and an international team of astronomers used several telescopes and observatories in La Palma, Spain, and in Hawaii to study the Sausage galaxy cluster, which is located in the constellation Lacerta (the Lizard) in the Northern Hemisphere sky. Their research was detailed in the April 24 edition of the Monthly Notices of the Royal Astronomical Society.

The team plans to sample a larger number of galaxies soon to try to catch more of these comatose mergers in the act.

Follow Elizabeth Howell @howellspace, or Space.com @Spacedotcom. We’re also on Facebook and Google+. Originally published on Space.com.

A giant, swirling plume of superheated plasma churned above the surface of the sun for 40 hours last week while a NASA spacecraft looked on.

NASA’s sun-studying Solar Dynamics Observatory (SDO) captured dramatic time-lapse video of the solar tornado, which raged from Sept. 1 through Sept. 3.

The mass of plasma “was stretched and pulled back and forth by powerful magnetic forces but [was] not ripped apart in this sequence,” SDO team members wrote in a description of the video. “The temperature of the ionized iron particles observed in this extreme ultraviolet wavelength of light was about 2.8 million degrees C (or 5 million degrees F).”

This isn’t the first solar twister SDO has observed. Last year, for example, the spacecraft recorded video of an enormous tornado spinning off the sun. And in 2011, SDO watched as another tornado — this one about five times the size of Earth — gyrated at speeds of up to 186,000 mph (300,000 km/h).

For comparison, tornado wind speeds here on Earth top out at around 300 mph (480 km/h).

This image from NASA’s Solar Dynamics Observatory captures a “tornado” swirling on the sun in early September 2015.
Credit: Solar Dynamics Observatory, NASA

The $850 million Solar Dynamics Observatory mission, which launched in February 2010, studies the sun with three different instruments, collecting data that help scientists better understand the solar magnetic field and space weather.

SDO was the first mission launched under NASA’s Living With a Star Program, which is probing the causes of solar variability, and the impacts of this variability on Earth.

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

Credit: NASA/JPL-Caltech/Edited by Space.com’s @SteveSpaleta

Paul Sutter is a research fellow at the Astronomical Observatory of Trieste and visiting scholar at the Ohio State University’s Center for Cosmology and Astro-Particle Physics (CCAPP). Sutter is also host of the podcasts Ask a Spaceman and RealSpace, and the YouTube series Space In Your Face. He contributed this article to Space.com’s Expert Voices: Op-Ed & Insights.

James Clerk Maxwell had no idea what he was doing. To be fair, he knew what he was doing when it came to making perhaps one of the greatest scientific achievements of the 19th century: showing that electricity and magnetism were really just two sides of the same electromagnetic coin. Oh yeah, and he discovered what light is. Yeah, light. You may have heard of it. His insights allowed him to realize that it’s all unified under a single force: the light from the sun, the magnet stuck to your fridge, and the electricity in your smartphone. 

What he may not have realized was that the theory he developed sowed the seeds of a revolution that would sweep away the old Newtonian Order and usher in a new Age of Relativity. His results would usher in an entirely new worldview: a paradigm where space and time are not separate entities, but unified as a single space-time. Whoa.

Maxwell also had a beard that would make the bartender at your local gastropub jealous. But it was the explaining-light-bit that stuck in everybody’s collective craw. Maxwell identified light as a self-sustaining wave of electricity and magnetism (an “electromagnetic wave,” if you will), but if it’s a wave, what is it waving? Sound waves need air to wave around, and ocean waves need water to wave around, so what do electromagnetic waves … wave around?

The stuff of light

“Ah-ha,” says Maxwell in my fictional argument, “The new theory itself gives a clue.” The speed of this newfangled electromagnetic wave is a constant, with the exact number depending on the properties of magnetic and electric fields in a vacuum.

A vacuum? Where there’s absolutely nothing else? Why, that’s the domain of the aether. I get it now: Light is a wave of aether! Ta-da! Right. The aether. The stuff, the goop, the nougaty goodness that permeates the entire universe. If there’s nothing somewhere, then that somewhere is full of aether. There’s a reason that the word aether is unfamiliar to you post-19th century readers: Without knowing it, Maxwell’s insight into the nature of light would end up destroying the entire concept. 

But why did people think we needed some aether-stuff for light to wave around in the first place?

Galileo was the first to point out the obvious: all motion is relative. When I say something like “the ball is traveling at 50 mph towards me,” I implicitly add “relative to my head.” If I’m on a train, someone standing on the platform would add the speed of the train to the speed of the ball to get the “total” speed. Another interested observer, way out in space, would also add in the rotation and orbit of the earth. So what’s the real speed? The absolute, final speed? 

This idea of relative motion means that you can’t easily figure out that final speed. For example, a physics experiment performed on the train (say, testing how much my head would hurt after being hit with a ball) would not tell me if I was on a train or not. (Assuming it’s not accelerating. And the windows are shut. And so on. This is a thought experiment, alright?) 

You’ve seen this yourself. Throw a ball around on an airplane. After being restrained by the flight attendants, reflect on the fact that the ball behaved perfectly normally, despite the fact that you’re hurtling through the air at several hundred miles per hour.

How can we tell if we’re moving if … we can’t tell that we’re moving?

A universal reference

Enter the universal reference frame. A “background” to the universe that stays fixed and unmoving for eternity, giving us all a stage to play around on. That’s the place where we can measure the “total, real, final, I’m serious, guys” speed. Oh, and a master clock, too, to keep perfect time. That’d be useful.

This assumption of a fixed background formed one of the bases of Newton’s laws of motion. It was in this universal frame that he could write down the mathematics that he needed to get the job done. All motion in the universe is relative to that background.

Back to Maxwell. Since the speed of light was a constant in the vacuum, and the vacuum was filled with aether (as the thinking went back then), then the aether must be in the universal reference frame. In other words, the aether itself was the universal Newtonian background. If we’re moving around relative to that fixed background, we can detect our motion relative to it — and hence deduce the properties of the aether — by measuring changes to the speed of light. Another ta-da, and a huzzah to boot! 

So, by golly, let’s go out and do it. And that’s what a bunch of people, including Albert Michelson and Edward Morley did. Or more correctly, attempted to do. By building a sensitive apparatus and comparing the speed of light moving in different directions at different times of day, they thought they could measure the motion of the Earth relative to the background aether. Key word: thought.

That’s the problem: try as they might, the Michelson-Morley experiments failed to detect any changes to the speed of light . At all. Ever. Even when they asked nicely. No matter what, no matter how fast or in what direction the Earth was moving, their measured speed of light remained stubbornly fixed. 

This is what’s called a “problem.” On one side you have the Newton worldview, saying there must be an absolute reference frame, and on the other you have Maxwell plus the M&M (wait, that may be copyrighted, let’s go with M-M) worldview, saying there is no evidence of the aether, and hence no absolute reference frame. Who wins? I mean, they’re all pretty smart, so it’s tough.

So that’s what they mean by ‘relativity’

Along came Einstein to settle the dispute. And by “settle” I mean “pick Maxwell.” Einstein took the old notions of Galileo’s relative motion and took them to the extreme. Yes, everything is relative. And that’s it. No absolute reference frames. No aether. No master clocks. Just relative motion. Things can only be said to be “moving” relative to another observer.

What’s the big deal? Special Relativity is the big deal. By disregarding the absolute reference frame (and the aether along with it) the world has some weird properties. For example, there is now a universal speed limit. That’s right: we’ve traded a universe with no speed limits but a fixed background to one with a speed limit but free of any aether. 

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Credit: SPACE.com

And then Einstein took it to the next level as only Einstein could: not only are the laws of motion the same in every inertial (jargon alert: “non-accelerating”) reference frame, but all physics are the same. Including Maxwell’s equations. Including Maxwell’s speed of light. Which is a constant in one frame. And is thus constant in all frames. 

And there’s our universal speed limit: the speed of light in a vacuum. Constant for one, and thus constant for all, no matter how fast you’re moving.

Switching to a universe with Special Relativity comes at a price. After all, with great power comes great relativity. Ha-ha, sorry, couldn’t resist. But, really, there is a price. No longer can space and time be thought of as separate things. There is only space-time. That doesn’t sound like a big deal, but now the universe is a lot stranger: without an absolute reference frame, different observers can disagree about lengths, or the duration of time, or even the ordering of events. Sounds spooky.

It is all now, as they say, relative. What does this mean for you and me? To be continued in my next essay…

Learn more by listening to the episode “What is spacetime? (Part 1)” on the Ask A Spaceman podcast, available on iTunes and on the Web at http://www.askaspaceman.com.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Space.com.

On Thursday, Sept. 10 the waning crescent moon, Venus and Mars will appear in an eye-catching arrangement in the early-morning sky. Credit: European Southern Observatory

If you want to see an eye-catching celestial display involving a slender crescent moon and two bright planets, be sure to wake up an hour before sunrise on Thursday morning (Sept. 10).

You might also want to make sure that you have a clear and unobstructed view toward the east, as this nice array of the moon and planets will be relatively low — only about 15 degrees above the horizon. (Your clenched fist held out at arm’s length measures about 10 degrees.) So you’ll need to make sure that there are no trees or buildings any higher than a fist and a half; otherwise your view may be partially or completely blocked.

The most obvious celestial object will be the crescent moon, a sliver of yellow-white light only 7 percent illuminated by the sun. To the right of the moon will be the second-brightest object of the night sky: the planet Venus. Venus, which had been a prominent evening object since the start of this year, finally relinquished the title of “Evening Star” less than a month ago and disappeared from view before beginning to appear in the morning instead. [Best Night Sky Events of September 2015 (Stargazing Maps)]

In the hour before sunrise Thursday morning, Venus and the crescent moon will provide a pleasing celestial tableau as they ascend the eastern sky side by side, just 2.5 degrees apart. Use binoculars to better appreciate the appearance of the full globe of the moon, its grayish-blue tone delicately interposed between the brighter sunlit crescent and dark background sky. Leonardo da Vinci was the first to recognize the faint glow of the moon’s globe  as Earthshine — light from the sun, reflected off Earth to the moon and then back to Earth.

Skywatching Triple Treat: Mars and brilliant Venus will shine near the crescent moon before sunrise on Thursday, Sept. 10. This Starry Night sky map shows how the trio will look risking in the eastern pre-dawn sky at 6 a.m. local time as viewed from mid-northern latitudes.
Credit: Starry Night Software

Finally, there is much fainter Mars. If you extend an imaginary line from Venus through the moon and continue that line for a bit more than twice the distance between the two, you will come to the Red Planet. Don’t look for red, though; in actuality, Mars appears to glow with a yellowish-orange color.

Mars shines at a magnitude of +1.8. For comparison, Venus dazzles at magnitude -4.5, or 316 times brighter than Mars!

One of the reasons that Venus is so bright in the sky is because of its high albedo, or the amount of light it reflects back into space. This albedo comes from the permanent cloud layer that surrounds the planet; the clouds reflect about 75 percent of the sunlight they receive back toward Earth. Another reason has to do with distance. Currently, Venus is 34.4 million miles (55.3 million km) from Earth. In contrast, Mars is 230.3 million miles (370.6 million km) away — more than 6.5 times farther compared with Venus. Mars is also considerably smaller than Venus.

But don’t feel too sorry for poor dim Mars, for things will change in the coming months. Right now, Venus is slowly pulling away from the Earth, while Mars is slowly approaching.

Fast forward to next spring: Mars will approach to within 46.8 million miles (75.3 million km) of Earth on May 30 and will glow at a brilliant magnitude of -2 — its best apparition in over a decade. Venus, meanwhile, will be completely lost from view, deeply imbedded in the glow of the sun.

Editor’s note: If you capture an amazing view of Mars, the moon and Venus — or any other night sky view — and want to share it with Space.com, send images and comments in to managing editor Tariq Malik 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 News 12 Westchester, N.Y.  Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Credit: NASA/SDO/mash mix: Space.com

On Sunday morning, Sept. 13, there will be a partial eclipse of the sun visible in southern Africa, the Indian Ocean and parts of Antarctica. Here it is seen from Cape Town, South Africa, where it will be at its maximum. Credit: Starry Night Software

The penguins are in luck, as are some skywatchers in the Southern Hemisphere: A solar eclipse will be visible from Antarctica, southern Africa and the Indian Ocean on Sunday (Sept. 13).

The best view of this partial solar eclipse — the third of four solar or lunar eclipses this year — from an urban area will be from Cape Town, South Africa, where the moon will cover a maximum of 30 percent of the sun. The eclipse will begin in Cape Town just as the sun and moon are rising at 6:49 a.m. local time. Early risers will see a tiny bite out of the sun. At 7:43 a.m., the eclipse will reach its maximum, and by 8:50 a.m., it will be over.

This eclipse will be visible throughout South Africa, and also in southern parts of Madagascar, Mozambique, Zambia, and Zimbabwe. It will also be visible over a wide area of the Indian Ocean and Antarctica (which is good news if you happen to be a penguin). [Solar Eclipses: An Observer’s Guide (Infographic)]

The best way to observe a partial solar eclipse is with a filter specifically designed for viewing the sun. Stores specializing in telescopes sell these filters. Safe “eclipse shades” are often widely available prior to an eclipse. A No. 14 welder’s glass also works well, and is available from specialized welding shops. The ordinary, No. 12 welder’s glass sold in hardware stores to protect welders’ eyes from extremely bright light does not provide adequate protection from the sun.

If you don’t have a proper solar filter, you can view the partially eclipsed sun with a pinhole camera by punching a hole about a millimeter in diameter in a piece of cardboard. Natural “pinholes” created by leaves on trees or reflections from a building’s windows will also work.

Under NO circumstances look directly at the sun, even with sunglasses, as you can quickly cause permanent damage to your eyes. If a small magnifying glass can light a fire in seconds, think what will happen to the retina of your eye by staring at the sun.

Editor’s note: As always, we welcome your pictures of the partially eclipsed sun; a solar filter on your camera will be essential. (The sensor in your camera is just as easily damaged by the direct sun as are your eyes.) Try to get a landmark or tree in the foreground to give a sense of scale. You can send images and comments for possible use in a future story or gallery to managing editor Tariq Malik at: spacephotos@space.com.

This article was provided to Space.com by Simulation Curriculum, the leader in space science curriculum solutions and the makers of Starry Night and SkySafari. Follow Starry Night on Twitter @StarryNightEdu. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

The U.S. Air Force intends to use an Orbital ATK satellite platform for the STPSat-6 mission. Shown above is an artist’s concept of the GEOStar-1 platform Orbital ATK offers for national security missions in geostationary orbit. Credit: Orbital ATK

WASHINGTON – The U.S. Air Force hopes to build an experimental satellite that would detect nuclear explosions and monitor the space environment from geosynchronous orbit, the service said in an Aug. 24 announcement.

The Space Test Program Satellite (STPSat) -6 would be the latest in a series of spacecraft developed under a Defense Department program to field space capabilities quickly in response to emerging military needs.

STPSat-6 is notionally scheduled to launch in late 2018 as the primary payload on a rocket to be selected via competition, presumably between SpaceX and United Launch Alliance, the Air Force said. That mission, called STP-3, will place multiple satellites into geosynchronous orbit, the statement said. [The Most Dangerous Space Weapons Ideas Ever]

In a request for information posted to the Federal Business Opportunities website, the Air Force’s Space Test Program at Kirtland Air Force Base in New Mexico said it was looking for input from industry on how to build and fly the satellite. The service plans to use the resulting input to develop its acquisition strategy.

The primary payload aboard STPSat-6 is the Space and Atmospheric Burst Reporting System, or SABRS, which provides nuclear detonation detection and space environment data. The payload would complement nuclear detection sensors currently aboard GPS satellites.

STPSat-6 also could include as many as eight secondary payloads from the Space Test Program office, the Air Force said.

Project officials envision providing a partially assembled satellite bus from Orbital ATK of Dulles, Virginia, as government furnished equipment. Orbital ATK currently has the hardware at its Beltsville, Maryland facility, the notice said.

The Air Force expects to spend $65 million on the program from 2016 to 2026 and hopes the satellite would operate for at least eight years, the posting said. The satellite would be placed into geostationary orbit between 80 and 120 degrees west longitude, the notice said.

STPSat-6 could be compatible with the Multi-Mission Satellite Operations Center (MMSOC), a satellite control architecture designed primarily for experimental and Operationally Responsive Space missions. The MMSOC was developed by Lockheed Martin along with the Air Force Space and Missile Systems Center’s Space Development and Test Directorate and is viewed by some as the ground system of the future.

Responses from industry are due Sept. 24.

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