April 26, 2011 at 17:47 pm | Leave a Comment
Come on Down to the Carnival of Space
Every week, the work of a hardy band of science writers, specializing mostly in space and astronomy topics, is featured in a roving blog entry called “The Carnival of Space.” We all take turns hosting it, highlighting the writings of 16 of us spacey scriveners. This week, the Carnival is playing out over at The Next Big Future blog. Check it out! You never know what you’re going to learn as you surf the cosmic midway at the Carnival!
On the mountain where I live, we’ve been getting blasted with snow off and on the past week or so. It’s the last gasp of winter, even as we’re truly into spring. While the snow is much-needed (it’s very dry here and the specter of forest fires is looming already this year), it means that we don’t get to see much of the Sun, so I turn to my online solar sources for some virtual sunlight.
Two sites I visit pretty regularly are the STEREO mission Web pages and the Solar Dynamics Observatory (SDO) web pages. These two space-borne missions are studying our star and sending back some really spectacular images of its busy surface and atmosphere.
The next couple of years should be exciting times for solar observers, as the Sun moves into its period of maximum activity. We’ve already seen some pretty spectacular outbursts, and there’s more to come.
Even though we evolved in the light of the Sun, and despite the fact most life on Earth thrives on heat and warmth from this nearby star — and despite the great knowledge we have about the Sun – there’s still much to be explained about its behavior, its evolution, and its eventual demise.
Yet, that demise is billions of years in the future — what concerns many of us is the Sun of today.
Missions like STEREO and SDO tell us a great deal about the Sun’s activities, and help us understand its influence on our part of the solar system. The Sun and Earth are linked together not just as star and planet, but as members of a coupled geomagnetic system. The solar wind (that stream of charged particles that continually blows from the Sun), tangles with the magnetic field of our planet. The stronger the solar wind, the stronger our magnetic field reacts.
The local effects are sometimes no more than a beautiful display of northern or southern lights. But sometimes, the Sun’s belches affect technology on Earth.
Understanding the Sun is important in the grand scheme of human concerns. It warms us, but it can also take away our telecommunications and electricity.
So, marvel in the Sun. Enjoy its light. Revel in the fact that it keeps life going even as it poses a threat to our planet with its fiery outbursts.
And, remember that we’re still learning many new things about our nearest star every day.
April 25, 2011 at 11:13 am | Leave a Comment
The Answer to the Question…
How do you search out unusual types of “cosmic stuff” such as dark matter and antimatter? The response: you do particle physics. Now, what’s particle physics? It’s the science of understanding the makeup and actions and effects of particles (atoms and their constituent components the electrons, quarks, etc.) that make up matter in the universe.
Cosmic rays are a big part of particle physics. They are pieces of atoms called “subatomic particles” that are very energetic. They zip around the universe at high speeds, they can penetrate our planet’s atmosphere and the surface, and even your body.
The next shuttle launch (the last one for Endeavour) will take a unique experiment into space called the Alpha Magnetic Spectrometer (AMS for short). It will be left on the International Space Station and spend some time doing particle physics. In its search for antimatter (which is the “anti” version of regular matter), the AMS will look for what’s called an “antihelium” nucleus occurring naturally in the universe. This “stuff” has been observed before in collider experiments where they have been created briefly during high-speed particle collisions. The instrument is sensitive enough to detect such antimatter at tremendous distances — out to the limits of the expanding universe (where, in its early moments, there may have been antimatter created as a part of the birth of the cosmos).
The AMS also sets its sensitive sights on the detection of dark matter, that stuff that appears to make up some 95 percent of the mass of the entire universe. There’s a LOT of it out there, and eventually we’re going to find out what it is. The AMS will look at the background amounts of positron, anti-proton, or gamma-ray flux (or type of flow). If there are peaks (or jumps) in the flux, then this may tell us about the presence of dark matter (and what it is).
Of course, since the AMS will be in space, studying space, it will give us a lot of information on the cosmic ray counts we encounter in near-Earth space. Cosmic rays come from a variety of sources (including supernova explosions, the Sun, and so on), and knowing the cosmic ray environment at both normal and peak levels helps us understand their role and existence. In addition, anybody venturing off Earth — whether to the Moon, the ISS, Mars or wherever — has to be continually aware of the cosmic ray levels. These babies are lethal in high doses!
So, how does this weird-looking instrument do its work? It has a set of detectors that are “interested” in various particles. For example, the transition radiation detector clocks the speeds of very high-energy particles, as does the ring-imaging Cherenkov detector. The AMS also has a superconducting magnet that is strong enough to bend the path of a charged particle and allows it to be identified. Other instruments measure the energy of the particles as they pass through, and give some indication of their coordinates in the magnetic field of the superconducting magnet. This all makes sense once you understand that these particles are creatures of their magnetic environments and so using speed detectors and magnets to measure their characteristics is the way to go.
While much subatomic physics can be done on the ground at places like CERN and Fermilab and Brookfield National Laboratory (among others), such experiments are usually better conducted in space, away from the Earth’s environment and where the conditions can be more easily understood. This flight of the AMS module (officially called AMS-02) is another step in stretching our understanding of the smallest particles (and their actions). For more information about AMS-02, visit the instrument Web page, where you’ll find introductory material, images, and videos.
April 22, 2011 at 11:00 am | Leave a Comment
So, Help Take Care of It
Earth as seen by Voyager 2 at a distance of 6.1 billion kilometers, outside the orbit of Pluto. Courtesy NASA.
See how fragile it is? How small? How does that make you feel? What thoughts does it engender in your mind about the preciousness of this world? Think you might want to do your bit to help preserve it as a safe place for everyone to live? Celebrate Earth Day, 2011 by helping your home planet in some way.
As the late Carl Sagan said in his book Pale Blue Dot:
That’s here, that’s home, that’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
(For the rest of this highly inspiring quote, go here.) We can make a difference, and it’s not all that hard. Keeping our planet healthy knows NO political agenda, no race, creed, gender issues, and is completely in harmony with the cosmos. So, help do it.
April 21, 2011 at 17:24 pm | Leave a Comment
The Last Flights of the STS Fleet
As NASA winds down its space shuttle missions — Endeavour launches on April 29 and Atlantis is scheduled for late June — it’s kind of hard to think that after those flights, there will be no direct access to space via NASA. The shuttles, like the Apollo spacecraft before them and the Gemini before those, have cemented themselves into the world’s consciousness and the U.S. national psyche.
They’ve made the ISS possible, they’ve carried many important science experiments into space, and they’ve proved that people can return to low-earth orbit again and again. It’s an honorable history and even though I won’t get a chance to ride a shuttle into orbit (that was once a dream of mine), I’m still proud of it and what it stands for.
Of course, the honor comes at the price of two sets of shuttle crews’ lives. As Gus Grissom once said, “The conquest of space is worth the risk of life.” I don’t think he thought his own life was to end so soon, and neither did the people aboard Challenger and Columbia have an inkling that theirs would end so spectacularly. But, they would have wanted the flights to continue; to do anything less would have detracted from the scientific cause to which they dedicated their lives.
I remember getting up well before dawn to see the first shuttle launch of Columbia on April 12, 1981. It seemed to us (after watching the much slower Saturn V launches of the Apollo era) that the shuttle was an agile system. It cleared the tower in just a few seconds and less than a minute later was arcing out over the ocean and into history. The first shuttle launch I saw in person was in the summer of 1993. As luck would have it, I was working on an HST instrument team, and so got a chance to see a second shuttle launch later that year when STS-61, flown by Endeavour, took off on the first Hubble Space Telescope servicing mission. That was an early morning launch and after it was over, we also had the chance to see HST fly over, giving us a first-hand feel for the orbital configuration the shuttle had to achieve in order to rendezvous with the telescope.
Watching a shuttle launch is an amazing experience. The sound comes well after the sight of the launch, and it hits you like a wall of “sensation”. I remember car alarms going off in the nearby parking lot at Press Site, and people were yelling in amazement.
Watching a shuttle land — as we did at White Sands in New Mexico in 1982 — was like watching an aerodynamic brick drop out of the sky and achieve a smooth landing. I still remember watching it glide to a soft landing, accompanied by T-38 chase jets. I can imagine it was pretty exciting for the folks onboard the shuttle and NOTHING like a landing that you or I might experience at an airport.
As I watch the preparations for the final flights, I can’t help but feel this palpable sense of history passing in front of our eyes. The shuttles have been part of our lives for some 30 years now. It’s tough to imagine that the last launches are coming up fast — and that soon NASA will have no home-grown access to space for its astronauts. They will, instead, be relying on the Russians to get them to and from low-earth orbit. And that, in the final analysis, is one of the most historically intriguing outcomes of the end of the shuttles. Our space program was spurred in large part in the late 1950s and 1960s by an incredibly rancorous competition with the then-Soviet Union. I often wonder what those early spacefarers at NASA and the Soviet space program would say if they knew today that NASA and Roscosmos were cooperating to get people to and from space together!
If you have a chance, be sure and watch the final launches of the space shuttles — either via NASA TV online, on TV, or if you can–in person. They’re incredibly powerful experiences. I hope that the next generation of space travelers will once again have a vehicle that can easily take them to orbit. I know that some are on the drawing boards and in testing. Hopefully, the historical changing of the guard from shuttles to those craft won’t take too long. I still want my ride!
April 20, 2011 at 9:30 am | Leave a Comment
That Hubble Went out to Play
And what a time it’s been! As you can see by this image, the most famous of the Great Observatories is still crankin’ out some stunning visions of the cosmos. Take this image, for example. It’s a pair of interacting galaxies, slightly farther along in their gravitational dance than the two I wrote about in my last entry. They are an interesting looking grouping called Arp 273.
The larger of the spiral galaxies in the group, known as UGC 1810, has a disk that is distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. Not only are these two cosmic behemoths changing each other’s shapes, but in the process, they’re spurring huge swaths of star-forming factories in the process. Those are the blublogs at the top of UGC 1810, and the bluish clouds of light at the tip of the lower galaxy. The image (embiggenate to see it better) shows a tenuous tidal bridge of material between the two galaxies that are separated by tens of thousands of light-years from each other.
Even more unusual are the off-center spiral patterns of each galaxy. Even if you didn’t know anything else about these galaxies, just one look at the off-kilter spirals would tell you that something has happened. In this case, one galaxy has dived through the center of the other. The smaller one probably sliced right through its larger companion above it in this image.
Notice how the spiral arms of UGC 1810 (the upper one) are warped off-kilter with respect to each other. The inner set is offset out of the plane of the galaxy. This must have been a titanic interaction!
As if this wasn’t weird enough, there’s also a possible mini-spiral in the upper right arms of UGC 1810.
Astronomers have seen many interacting galaxies — enough to be able to understand something of how and why they form. In this case, the larger galaxy of the pair is about five times more massive than its smaller companion. In unequal pairs such as this, the relatively rapid passage of a companion galaxy produces the lopsided or asymmetric structure in the main spiral. Also in such encounters, the starburst activity typically begins in the minor galaxy earlier than it does in the major galaxie. These effects could be due to the fact that the smaller galaxies have consumed less of the gas present in their nucleus — and that gas is what you need for stars to form. The gravitational shock waves spur “bursts” of star formation as the gas is compressed and heated during the interaction.
Arp 273 lies in the constellation Andromeda and is roughly 300 million light-years away from Earth. This image is just one of a stream of cosmic visions sent back by Hubble during its 21 years on orbit. Currently, the telescope is in great shape and should continue its work for some time to come.
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Copyright 2013, Carolyn Collins Petersen
Image of Horsehead Nebula: T.A.Rector (NOAO/AURA/NSF) and Hubble Heritage Team (STScI/AURA/NASA)
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