Is This the Death of Comet ISON?

By Corey S. Powell | November 28, 2013 1:25 pm


All along, astronomers knew that there was a real possibility that Comet ISON would not survive its passage by the sun. Now it seems like the comet may in fact be in the middle of a catastrophic disintegration, based on the latest images from NASA’s SOHO observatory. In this view, the comet’s tail splits in two, and the trail of the comet seems to shrink and peter out closer to the sun. It’s not clear yet what is happening, but this sure looks like the comet’s last act.

Comet ISON's last stand? NASA's SOHO spacecraft watches the trail of the comet toward the sun (blotted out in the middle). Credit: NASA/SOHO

Comet ISON’s last stand? NASA’s SOHO spacecraft watches the trail of the comet toward the sun (blotted out in the middle). Credit: NASA/SOHO

I previewed this possibility in my feature article in Discover magazine several weeks ago:

Maybe some diminished portion of the comet will remain intact; maybe it will break apart and disperse entirely. Either way, the public unraveling of Comet ISON will be cause for celebration, not mourning. “Comet ISON is an extraordinarily rare object,” says Carey Lisse of Johns Hopkins University, who is coordinating an international observing campaign. “It isn’t just hyperbole. We are going to go to town on it. And we are going to learn a lot.” Read More

MORE ABOUT: comet, Comet ISON

Comet ISON’s Moment of Truth

By Corey S. Powell | November 28, 2013 9:58 am

Astrophotographer Damian Peach captured this view of Comet ISON and its complicated tail on November 15. The field of view is 2.5°, five times the width of the full moon (Credit: Damian Peach)

Today is make-or-break time for Comet ISON as it reaches perihelion, the point closest to the sun. At 1:25PM EST the comet will zoom just 730,000 miles above the solar surface, traveling at a speed of about 225,000 miles per hour. You can track the comet’s progress live here. What happens during that passage will determine a lot about what the comet will look like in the next few weeks. Will it be a faint smear or a bright fuzzball with a long, lingering tail? Will it fizzle entirely? We are about to find out.

Depending on the comet (and also depending on your skills as an observer and your local weather conditions) you might actually be able to watch as Comet ISON swings around the sun today. That’s right: It is possible you could see it in broad daylight, though it won’t be easy and you need to be very careful. Our friends at Universe Today have created a great guide for how to look for Comet ISON right next to the much, much brighter glare of the sun. Read More

Watching “Ender’s Game” With My Science Goggles On

By Corey S. Powell | November 2, 2013 10:14 am

I get it: Ender’s Game is not a science movie, or even a hard sci-fi movie. In many ways it’s barely sci-fi at all, falling closer to the coming-of-age hero fantasy narratives of Percy Jackson or (ducking) The Phantom Menace. But it certainly contains plenty of science fiction tropes and settings, many of which dovetail with themes from other recent science fiction films. As I watched it, I was intrigued by these recurring elements, and by the ways they riff on–or contradict–recent scientific discoveries.

Ender Wiggin directs an epic space battle. Surely there's a better way. (Credit: Summit Entertainment)

Ender Wiggin directs an epic space battle. Surely there’s a better way. (Credit: Summit Entertainment)

Note that I’m referring only to the film, not the book. I’m not out to ruin anyone’s fun, so I’m avoiding spoilers as far as possible. I’m not here to write a critical review of Ender’s Game (it is entertaining for the younger audience, and let’s leave it at that). And my point is not to fact-check the movie, but to place it in the context of the things we actually know about biology, evolution, and the physics of other worlds. Science goggles engaged.
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A Novice Observer’s Guide to Comet ISON

By Corey S. Powell | October 25, 2013 2:35 pm

If you enjoy a dramatic spectacle in the sky, you have probably heard about Comet ISON, currently streaking toward the sun. (If you haven’t heard about it, bear with me—I’ll try to make it worth your while.) But the media coverage has been downright confusing. The first reports described it as a “comet of the century,” possibly as bright as the full moon. Then came some whipsaw downbeat news stories suggesting that the comet was fizzling and might have already begun to disintegrate.

Comet ISON as seen by the Hubble telescope on October 9, when it was 177 million miles from Earth. (Credit: NASA/ ESA/Hubble Heritage Team)

Comet ISON as seen by the Hubble telescope on October 9, when it was 177 million miles from Earth. (Credit: NASA/ ESA/Hubble Heritage Team)

No wonder DISCOVER readers have been sending in a steady stream of inquiries: What will Comet ISON really look like? When will it be visible? Where can I see it? Good questions. Time for some answers—and I’ll have a lot more to say about the science of the comet itself in an upcoming blog post. Read More

MORE ABOUT: comet, Comet ISON, skygazer

Hungry Rumblings from the Black Hole at the Center of the Milky Way

By Corey S. Powell | October 24, 2013 5:26 pm

There is a monster at the center of our galaxy: A black hole, known as Sagittarius A*, weighing 4.3 million times as the sun and measuring about 25 million kilometers (15 million miles) across. At present the monster is slumbering, betraying its presence only by a slight snore of radiation, but it was not always so calm. A new study using the Chandra X-ray Observatory has picked up echoes of past outbursts within the past few hundred years–moments when Sagittarius A* was wide awake, blazing a million times as brightly as it does today.

Sagittarius A* -- the giant black hole at the center of our galaxy -- appears quite dim in this composite image because very little material is falling into it. (Credit: NASA/UMass/D.Wang et al; NASA/STScI)

Sagittarius A* — the giant black hole at the center of our galaxy — appears dim in this composite image because very little material is falling into it. (Credit: NASA/UMass/D.Wang et al; NASA/STScI)

The idea that a black hole can be bright seems paradoxical at first. In reality, the emission comes not from Sagittarius A* itself but from material about to be swallowed up by the hole. As gas spirals into the black hole it grows ferociously hot and gives off all forms of radiation, including energetic X-rays. The fact that Sagittarius A* is currently dim in X-rays indicates that the hole is currently on a starvation diet. (It’s completely invisible in ordinary light, but that is due in large part to obscuring clouds that lie between there and here.)

So what happens when it is feeding time at the galactic center? That’s the question that Maïca Clavel of AstroParticule et Cosmologie in Paris, along with a group of collaborators, wanted to find out. Read More

Saturn’s Endless Beauty

By Corey S. Powell | October 21, 2013 9:42 am

Saturn is probably the single most iconic image in all of astronomy–so iconic that it was, literally, the official Discover magazine icon for a number of years. Yet, amazingly, scientists continue to find new ways to look at the ringed planet, uncovering details never before seen by human eyes. If you follow space images, you probably saw the stunning polar view of Saturn, taken by NASA’s Cassini spacecraft from a height of 935,000 miles. And that picture tells only a small part of the story.

Backlit Saturn shows rings, planet, and an intricate system of shadows in ways impossible to see from Earth. (Credit: NASA/Cassini/Gordon Ugarkovic)

Backlit Saturn shows rings, planet, and an intricate system of shadows in ways impossible to see from Earth. (Credit: NASA/Cassini/Gordan Ugarkovic)

Two things that got largely overlooked in last week’s gasping news coverage. First, the image was taken by Cassini and transmitted back to Earth while the federal government was officially shut down–a poetic reminder of what humans can achieve when they are working together effectively. Second, that even while NASA employees were on furlough, other space enthusiasts were still hard at work making good use of the data NASA was already collecting.

Among those enthusiasts is Gordan Ugarkovic, a self-described “guy who does programming for a living…but in free time I like to fool around with image processing.” Modesty be damned, what he really does is quite magical. He digs through Cassini images released to the Planetary Data System and creates his own color versions of images that NASA has released only in grayscale (what you and I would call “black & white”). The image I’m showing here is another one of his–a different view than the one that stunned the world last week. I highly recommend visiting Ugarkovic’s Photostream for more fabulous space views.

But wait–there’s more. NASA has just released another landmark image of Saturn, also taken by Cassini. The impact of this one is not quite as immediate. In its own way, though, it offers just as much head-spinning beauty (click below for a better look). Here we get a double dose of novel perspective. We are seeing Saturn as it appears from behind, on the other side away from Earth, looking back at the sun. And we are looking at the planet and its rings not in light but in infrared rays.

Slice of Saturn--an infrared view of the rings and the heat of the planet.(Credit:NASA/JPL-Caltech/University of Arizona/Cornell)

Slice of Saturn–an infrared view of the rings and the heat of the planet.(Credit:NASA/JPL-Caltech/University of Arizona/Cornell)

Adjust your perspective–imagine you are watching Saturn eclipse the sun, watching through a slit-shaped window in your spacecraft–and you begin to appreciate what you are seeing. The colors are not real; instead they represent the wavelength of the infrared rays, with blue representing the shortest (“hottest”) and red denoting the longest (“coolest”) emission. Because you are viewing Saturn from behind, all of the usual logic is turned on its head.

The middle rings, which appear bright from Earth, are dark here, because they are thick with particles that block the sun’s light. The outer rings, which normally appear faint, stand out bright here because they contain fine particles that scatter light like cigarette smoke. (NASA, being more health-conscious, likens the effect to the scatting of headlights off fog on a dark night.) The inner rings are somewhat bright as well, because they contain fairly transparent particles that let sunlight shine through. In the extended version of the image, you can even see the extremely fine ice particles blasted out of geysers on Saturn’s moon Enceladus.

Older infrared image of Saturn, released in 2010, shows seasonal heat (red) at the planet's south pole. (Credit: NASA/JPL/ASI/University of Arizona)

Older infrared image of Saturn, released in 2010, shows seasonal heat (red) at the planet’s south pole. (Credit: NASA/JPL/ASI/University of Arizona)

Then–whoa, Saturn itself is red! That’s because you are looking at heat emitted by the planet. You can see cloud patterns and weather systems in silhouette, visible in the places where they block the heat escaping from Saturn’s atmosphere. This image contains a staggering amount of information. It show the effects of seasons and weather systems on Saturn, it shows the structure of the rings, it shows the size of the particles in the rings, it even shows what the whole ring system is made of.

Spectacular all around. And knowing how things work, more Saturn beauty is on the way.

Follow me on Twitter: @coreyspowell

MORE ABOUT: Cassini, Flickr, NASA, rings

Crowdsourcing Astronomy: DISCOVER Readers Fight Asteroid Threat

By Corey S. Powell | October 15, 2013 10:47 pm

Four months ago, NASA issued what the agency—in all its acronym-loving glory—called an “RFI for the Asteroid Grand Challenge.” Translated into English, that means the agency was opening its doors to outside ideas about how to locate, study, and deflect potential Earth-threatening asteroids. (RFI stands for “request for information.”) More than 400 organizations and individuals responded.

NASA's concept for capturing and towing a small asteroid could be modified to deflect a potential threat. (Credit: NASA)

NASA’s planned mission to capture and tow a small asteroid for scientific study could be modified to deflect a potential threat. (Credit: NASA)

On September 4, NASA announced that it had identified 96 submissions that merited further study. Because of the insane government shutdown there has been little progress in that direction, but that hasn’t prevented the general public from continuing to think through the challenge. Over the past few weeks, DISCOVER readers have sent in a number of provocative ideas, written in response to my September and October Out There columns about asteroid hazards.

The readers’ solutions may not be practical, exactly, but even the most outlandish ideas contain hints of practical ways to control our destiny. There’s also an intriguing theme running through these suggestions: turning the threat around and using asteroids to our advantage, an astronomical version of natural pest control. Read More

After the Higgs Boson: A Preview of Tomorrow’s Radical Physics

By Corey S. Powell | October 11, 2013 10:51 am

I don’t mean any disrespect when I say that the Higgs Boson is yesterday’s news. In some ways, that is the very definition of what qualifies something for a Nobel Prize: a discovery that has already established its lasting importance and shown the way toward deeper insights. The foundational papers by Peter Higgs and Francois Englert, his Nobel-co winner, were published in 1964–nearly a half century ago. (Several other researchers also contributed to the work around this time, but are not recognized as part of this year’s Nobel prize.)


Simulated particle event at the Large Hadron Collider shows a “supersymmetry event”–a long-sought indicator of fundamental physics unity. (Image courtesy of Matevz Tadel, UC San Diego/CMS)

By the time researchers found strong evidence of the Higgs boson in 2012 at the Large Hadron Collider, or LHC, almost all physicists expected that it would be there; the shock would have been not finding it. The Higgs boson was the last missing piece of the standard model of particle physics, a model so well accepted that it is formally known–seriously–as the Standard Model. As with groundbreaking discoveries in general, the most interesting thing now is where it will lead next. So I conferred with one of the most thoughtful and articulate particle physicists I know, Joseph Lykken of Fermilab. Read More

The Real Stories and Real Science Behind “Gravity”

By Corey S. Powell | October 7, 2013 4:21 pm

3/4/14 update: Gravity got a lot of love at this year’s Oscars, including a best-director award for Alfonso Cuarón and well-earned nods also for cinematography and film editing. Looking back at the movie now, I have two big thoughts. First–no, it cannot happen for real. The space-debris disaster scenario and the orbit-hopping from shuttle to station to station are not physically possible. And second–that artificiality is far less important than the deeper realism of Gravity, which does an exquisite job capturing the beauty and danger of humans tiptoeing off our planet and into the infinite void.

Astronaut Mike Massimino, whom I associate with the George Clooney character in Gravity (see below), clearly agrees. After the Oscars he posted a video congratulating the cast and crew, and explaining exactly why he thinks the movie is advancing the cause of space exploration. By coincidence, President Obama released NASA’s 2015 budget request a day later. The real-world support for Massimino’s vision of exploration is decidedly mixed. The agency gets funding to keep the International Space Station alive until 2024 and to start work on the exciting WFIRST space telescope, but overall NASA takes a slight pay cut from 2014.

Congress will undoubtedly make some changes. If you would like to have a say in the process, I urge you to contact your Senators and Representative.

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The Baffling Simplicity of Black Holes

By Corey S. Powell | August 20, 2013 12:53 pm

I’ve had black holes on the brain lately.* There’s been a flurry of related research announced lately, even the discovery of black hole-like vortexes in the Atlantic Ocean, and astronomers are keenly watching as a gas cloud is ripped apart by the monster black hole at the center of our galaxy. All of which has prompted me to think about the odd simplicity of how black holes work.

Black hole

A solitary black hole betrays its presence solely through gravity, which bends and warps the light of more distant objects in this illustration. (Credit: NASA/ESA and G. Bacon/STScI)

In fact, you might say that black holes are the simplest objects in the universe. Think of all the attributes you would have to list in order to describe the Earth. There are oceans, continents, clouds, volcanoes, animals, plants, people…really, all of science except for astronomy and its cousin disciplines is dedicated to describing our planet and the varied things that exist on it or in it. Black holes, in contrast, have only three defining attributes: mass, spin, and electric charge. List those three and you can paint a complete portrait of a black hole. Read More


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