The scale of things

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Highlights mine.

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The Making of a Monster, Caught by Accident | Phil Plait
Bad Astronomy | Monday, July 1, 2013, at 8:00 AM

One of the most overwhelming things we have learned from studying astronomy in the past century—and it’s quite a list—is that entire galaxies collide.

I cannot overstate how awe-inspiring that is. A galaxy is a vast thing: a self-gravitating collection of tens or hundreds of billions of stars, countless clouds of gas and dust massive enough to create billions more stars, and all of this (not including the dark matter, which we cannot directly see) spread out over 100,000 light-years—a million trillion kilometers.

By itself a galaxy is mind-crushing structure. But then to find that they can careen through space and physically collide with another such monster … it’s difficult to grasp the enormity of such an event.

And yet collisions happen, and they happen often. And when they do, the result can be such beauty as to make even the most jaded cynic weep:


^ The collision of two galaxies, a train wreck on a truly cosmic scale. Click to bronsonalphenate. Photo by ESA/Hubble & NASA, Acknowledgement: Luca Limatola

This is ESO 1327-2041, a pair of colliding galaxies located 240 million light-years distant from Earth, observed by the Hubble Space Telescope. One of the galaxies is a lenticular, a lens-shaped disk like a spiral galaxy without the spiral arms, and the other is a more normal spiral. At least, it used to be.

At some point, a few million years ago, the two galaxies first made a close pass, circled around, and then slammed into each other. It looks to me that the lenticular is passing right through the heart of the spiral, the two coincidentally centered on each other at the time we see this event, midcollision. The arms of the spiral wrap right around the lenticular, looking like a cosmic leukocyte about to engulf a marauding bacterium.

When galaxies collide, strange things happen. As they approach, the gravity of one pulls on the near side of the other more than the far side—that’s because gravity weakens with distance. The net effect is that the galaxies can get stretched out and distorted, and huge streams of stars can be drawn out or ejected from the parent galaxy.

< Diagram showing the forensics of the collision. Illustration by Keeney, et al. from their paper.

Look again at the picture. See the long fuzzy streak going up out of the galaxies? That’s just such a star stream. But it gets better; the bright knot near the top may actually be the nucleus of the spiral galaxy, tossed out by the interaction.

I phrase that cavalierly, but it’s an event so powerful words are grossly inadequate. There are millions of stars in that glowing plume. Millions. That’s how much might is locked up in an event like this; the power to heave around entire stars by the millions.

It makes the hairs on the back of my neck stand up.

This collision is not done; eventually the two galaxies will merge completely, their material mixed, and they’ll join into one larger galaxy. All the most massive galaxies in the Universe have undergone this process at one level or another, growing into their enormous status by mutual cannibalism.

And after all that, amazingly, the collision pictured is not why those galaxies were observed using Hubble in the first place! It just so happens that there is a much more distant quasar coincidentally near those galaxies in the sky. Quasars are intensely bright galaxies, ones that have monster supermassive black holes in their cores, actively gobbling down matter, heating it up to fierce temperatures, and blasting out light across the electromagnetic spectrum.

The collision of the galaxies has tossed out a lot of gas, and that material is absorbing the light from the quasar. This type of absorption is interesting to astronomers; it’s like a fingerprint telling you how far the quasar and gas are. Gas that is otherwise dark between us and the quasar can be detected this way. Given that quasars can be seen from billions of light-years away, the Universe has given us a method to map itself for free.

That’s why astronomers pointed Hubble at ESO 1327-2041: It happened to be between us and a more interesting quasar. Until Hubble’s clearer vision was set upon it, the galaxy was thought to simply be a peculiar type called a polar ring galaxy.

Oh, how I love astronomy! One of the most powerful and awe-inspiring events in the entire Universe, the collision between two huge galaxies, and its true nature was only discovered by accident.

But once found, the astronomers looked at it on purpose to learn more about it, and surprises are part of the fun. It’s a big Universe, full of such delights, and there’s still very much left to learn about it.

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Happy (or is it Merry?) Aphelion This Friday
Universe Today, David Dickinson | July 2, 2013


^ Solar apparent size- perihelion versus aphelion 2012. The red circles show the size of one disk superimposed over the other. Shot by the author with the same fixed focal length rig pictured below.

This 4th of July weekend brings us one more reason to celebrate. On July 5th at approximately 11:00 AM EDT/15:00 UT, our fair planet Earth reaches aphelion, or its farthest point from the Sun at 1.0167 Astronomical Units (A.U.s) or 152,096,000 kilometres distant.

Though it may not seem it to northern hemisphere residents sizzling in the summer heat, we’re currently 3.3% farther from the Sun than our 147,098,290 kilometre (0.9833 A.U.) approach made in early January.

We thought it would be a fun project to capture this change. A common cry heard from denier circles as to scientific facts is “yeah, but have you ever SEEN it?” and in the case of the variation in distance between the Sun and the Earth from aphelion to perihelion, we can report that we have!

We typically observe the Sun in white light and hydrogen alpha using a standard rig and a Coronado Personal Solar Telescope on every clear day. We have two filtered rigs for white light- a glass Orion filter for our 8-inch Schmidt-Cassegrain, and a homemade Baader solar filter for our DSLR. We prefer the DSLR rig for ease of deployment. We’ve described in a previous post how to make a safe and effective solar observing rig using Baader solar film.


^ Our primary solar imaging rig. A Nikon D60 DSLR with a 400mm lens + a 2x teleconverter and Baader solar filter. Very easy to employ!

Resume.

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A Perfect Volcanic Island and Plume | Phil Plait
Bad Astronomy | Tuesday, July 2, 2013, at 8:00 AM

On May 31, just before 9:00 a.m. local time, the International Space Station was passing over the small island of Gaua in the south Pacific. Well, small as seen from above the ocean; it’s actually a massive stratovolcano more than 3,000 meters (2 miles) tall from base to tip and 40 kilometers across.

But only the very top of it pokes above the water. Still, it provides a dramatic view from 420 kilometers (250 miles) above the Earth:


^ Gaua Island, a volcano in the southwest Pacific, seen ... FROM SPACE! Click to hephaestenate. Photo by NASA

This was taken by an astronaut on ISS, looking not too far from straight down on the volcano. The peak of the volcano is called Gharat, and you can see the obvious and perfectly formed plume made primarily of steam blowing from it to the east. The volcano is active and had been blowing out steam for about a month before this photo was taken.

I like how beautifully framed this picture is and how textbook the volcanic peak is. Gharat rises to about 800 meters above sea level, and has the lovely semicircular Lake Letas to the north and east. (I have to note that “Gharat” sounds Cardassian, and “Letas” Bajoran; perhaps I am simply too big a Star Trek dork.) The island, populated by 2,500 people, is the biggest in the Banks Islands group in the Republic of Vanuatu, east of northern Australia. These are all volcanic islands, though not all currently active.

I would wager a healthy sum that most people have never heard of this tiny island. I know a little about Vanuatu, but mostly because I’m fascinated by both volcanoes and pictures of them from space, so I’ve read about it before. This is a great reminder that we live on a huge planet, so spread out, that there are actually parts of it you weren’t even aware of. How much of Earth don’t you know? How much more is there for any of us to explore and discover? We all live here, after all. Shouldn’t we take the time to learn more about our home?

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Comet ISON: The Timelapse Hubble Movie
Universe Today, Nancy Atkinson | July 2, 2013


^ A false-color, visible-light image of Comet ISON taken with Hubble’s Wide Field Camera 3. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

The Hubble Space Telescope team has released a video of Comet ISON as it is tearing toward its encounter with the Sun, zooming at 77,250 km/h (48,000 miles per hour). The comet’s motion is captured in a timelapse movie, below, made from a sequence of pictures taken May 8, 2013. On that date, the comet was 650 million km (403 million miles) from Earth, between the orbits of Mars and Jupiter.

This sungrazing comet will come closest to the Sun in November 2013, and the debate is on whether it will dazzle the skies and be visible in the daytime or fizzle out due to its close proximity to the Sun.



The movie shows a sequence of Hubble observations taken over a 43-minute span, compressed into five seconds. In that 43 minutes, the comet traveled about 55,000 km (34,000 miles). ISON streaks silently against the background stars.

Source: HubbleSite

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Interacting ring galaxies designated as Arp 147. Credit: NASA, ESA, and M. Livio (STScI)

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Giant Magellan Telescope

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The beautiful music in the video below was composed by Pablo Garmón. Nice scoring, really nice. And more of his compositions can be heard at SoundCloud. Mr. Garmón applies those compositional skills and smoothed instrumentations that are appreciated, so much so that I relaxed into the listening, enjoying the subtle timbre distinctions. Most of his pieces forced me to swing in rhythm, naturally.

The music with the stunning aurorae in the video were such that I moved about four feet from the 23-inch monitor to listen and watch, full screen. Music, again, made my day!

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Time Lapse: Arctic Lightscapes | Phil Plait
Bad Astronomy | Tuesday, July 2, 2013, at 10:30 AM


^ A frame from the video Arctic Lightscapes showing dramatic sheets of green aurorae. Photo by Anneliese Possberg, from the video

The Sun has been getting a bit more active lately, blowing out the odd solar storm or two. These waves of subatomic particles march across interplanetary space, and when they hit the Earth, they spark geomagnetic storms. Those in turn can result in displays of the northern and southern lights, or the aurora (borealis for the north, and australis for the south).

Photographer Anneliese Possberg traveled to Greenland, Iceland, Norway, and Finland to capture the shows, and she created this stunning time-lapse video of them:



I love how it starts, with the Sun making its long, slow, shallow dive to the horizon. That’s a clear indication she was at a high latitude; at mid-latitudes like the United States and most of Europe, the angle the Sun makes toward the horizon is much steeper.

The odd motion of the water in the first few seconds of the video caught my attention as well. It wasn’t as jerky as I was expecting. Then I noticed some of the auroral streamers looked odd as well, and realized what was going on: Possberg was morphing from frame to frame, interpolating the motion between the shots. I described this in a post about a video from the Mars Curiosity rover; basically it’s just using a bit of math to smooth out the motion a bit. If an object appears in one part of a frame then is in a different place in the next frame, you can determine where it was at the moment halfway (or any fraction) between the two frames. It’s a perfectly fine thing to do, and it adds yet another unearthly level to the already surreal video.

As you watch, you’ll see most of the aurorae are green, which is normal. But there are also other colors that appear: purple, pink, even blue. All of these come from molecules and atoms of nitrogen and oxygen in the upper atmosphere, emitting light as they heal from their wounds after being slammed by subatomic particles from the Sun.

National Geographic has a story on how Possberg made this video, too, and it’s pretty interesting. She had the flu when she shot some of the video! That takes real dedication; it’s not like she was shooting these pictures in her back yard.

Right now I’m in Oregon for our Science Getaways trip. I’m really hoping the Sun gets some cosmic indigestion while we’re up there; those latitudes would be favored during a good aurora. I’ve never seen one myself, and given all these photos and videos I post, I think it’s about time I got my due.

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“If the stars should appear one night in a thousand years, how would men believe and adore; and preserve for many generations the remembrance of the city of God which had been shown! But every night come out these envoys of beauty, and light the universe with their admonishing smile.”

― Ralph Waldo Emerson, Nature and Selected Essays

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Occurrence of HighCurrent ZPinch Aurora as Recorded in Antiquity(pdf)

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Nice video!

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Happy Birthday, America! | Phil Plait
Bad Astronomy | Thursday, July 4, 2013, at 8:00 AM


^ Some states take their fireworks literally. Photo by QT Luong, from the video

My fellow Americans: I can’t think of a better way to honor our nation’s birthday than to watch natural fireworks erupting from our newest state. Turn up the volume, make this full screen, and watch Hawaii’s volcanoes celebrate the Fourth of July.



The photographer, QT Luong, has details about the video on the Vimeo page. You should also check out his web page, Terra Galleria, which has thousands of stunning photographs. These are seriously beautiful.

I just returned from a vacation in Oregon where I was surrounded by volcanoes, and it was truly amazing. When we left, and started our drive, for hours—once we were tuned to it—we could see the landscape sculpted by ancient and recent eruptions. Layers of lava swept over the land for hundreds of kilometers, and created eastern Oregon as we know it today.

Volcanoes are a powerful and majestic force that shaped a vast amount of America’s geography. That’s something worth knowing, on this day when we celebrate our country.

Tip o’ the caldera to Joe Hanson at It’s OK to Be Smart.

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With regard to the vimeo in the space ^ above, at first listen to the soundtrack, which I think is gorgeous, it seemed the sound of a pipe organ with several other musical instruments, made to sound like they’ve been played on an organ with exceptions perhaps of percussion, were composed via software with sounds of a chorus singing lyrics; to my ears, the track sounded like church music. I read the vimeo comments, and discovered the video maker alluded the video as something spiritual, a contemplative experience, I guess. So, my ears were correct at first listen.

Furthermore, the domain of the music’s composer or distributor is gr, which is Greek. Again, the original soundtrack, titled Ride of the Dark Knight, might have been composed with an intention to sound like (Greek?) church music with organ and voices singing or chanting—that’s okay by me—then, selected by a video producer for a beautiful time-lapse about Hawaiian volcanoes. Now, there might be connections, aesthetically, musically, philosophically and scientifically, but I don’t know what the video producer’s were, exactly. My surmises about them would be excitedly boring. You see, listening too critically and turning music curiosities into research can be a downer! Wish I hadn’t done so, actually. Just some thoughts.

~ A.

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Edit. If the video producer’s intent was communion with nature, then I understand perfectly the connections he was creating with volcanoes, lava, heat, steam, wind, clouds, beauty, color, Milky Way.

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Sphinx Observatory, Jungfraujoch, Switzerland

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[infrastructure] Sphinx Laboratory | The Sphinx Laboratory is part of the Sphinx building and belongs to the Sphinx AG Jungfraujoch, a subsidiary company of the Jungfraubahn Holding AG. It is at the free disposal of the Foundation. It has an astronomical dome, two large and two small laboratories, a workshop, two terraces for scientific experiments, and a weather observation station. The observation instrument in the astronomical dome is a 76 cm telescope with Cassegrain and Coudé focus, and is part of the solar spectrometer of the Institut d'Astrophysique et de Géophysique de l'Université de Liège, Belgium, and the LIDAR experiment run by the École Polytechnique Fédérale de Lausanne, Switzerland. Many long-term experiments are permanently installed in the Sphinx laboratories. Space for other projects and campaigns is available upon request.

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^ Julie Thi Underhill | VIMEO NOTES.

In December 2011, I visited Jungfraujoch, the highest altitude railway station in Europe. The Jungfraujoch is a col or saddle between the Mönch and the Jungfrau in the Bernese Alps, on the boundary between the cantons of Bern and Valais, inside the Jungfrau-Aletsch Protected Area. This region is a UNESCO World Heritage Site.

This very brief panorama, filmed from the Sphinx Observatory deck, overlooks the Grosser Aletschgletscher (Great Aletsch). Although it seems like a snow-covered valley, it’s actually a 14-mile-long glacier, the largest in the Alps. Surrounded by dozens of crags and mountains, it’s truly a spectacular and stunning sight to behold from an altitude of 11,332 feet.

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Jungfraujoch & Gornergrat | Gallery with a load of photos from 2004 to 2013.