"The Earth's atmosphere is an imperfect window on the universe... atmospheric turbulence blurs the images of celestial objects, even when they are viewed through the most powerful ground-based telescopes." -John Bahcall There's no doubt that the Hubble Space Telescope has given us some of the most spectacular, high resolution views of the Universe. From the most distant galaxies ever seen to stars here in our own galactic backyard, the Hubble Space Telescope has simply dwarfed anything we've been able to do from Earth's surface.
(Image credit: Bill Drelling.)
This is the globular cluster NGC 288, separated by just over 1 degree from the famed Sculptor Galaxy, as seen through a simple 3" telescope. Larger telescopes can, of course, do better, but from high above the Earth's atmosphere, Hubble's 2.4 meter primary mirror has given us this view of this remarkable object.
(Image credit: ESA/Hubble & NASA.)
Absolutely amazing! For over 20 years, Hubble has been returning images like this, with a resolution of just a couple of hundred-thousandths of a degree!
The reason it can do this, of course, isn't its size. At 2.4 meters, Hubble is pretty large, but we have plenty of 8-meter and 10-meter telescopes here on Earth, which could get much better resolution than Hubble if they were in space. No, Hubble's advantage is its location.
(Image credit: NASA, retrieved from the Urban Astronomer.)
While ground-based telescopes have the entire atmosphere to contend with, complete with turbulent air, a slew of different, moving layers, and intervening molecules, Hubble is literally above all that. Despite their extra size, ground based telescopes haven't been able to compete because of the atmosphere.
But a new technology -- adaptive optics -- is changing all of that. Here's how it works.
(Image credit: Gemini Observatories, NSF / AURA, CONICYT.)
You start by shooting a powerful laser with very well-defined frequencies, like this sodium laser, creating a guide star that's in the direction you're taking your observational data. You're seeing light from all of the actual stars, galaxies, etc. -- you know, the real observing targets -- as well as your artificial guide star. The beauty of using a sodium laser is that, around 100 km up, there's a thin layer of sodium in Earth's atmosphere that will absorb and re-emit the light back towards your telescope.
All the light that comes in, both from your real targets and from your guide star, gets distorted by the atmosphere. But, since you know what your guide star is supposed to look like, you can take the blurred, incoming signal from the guide star, and compute what type of weird, fun house-style mirror you'd need to un-blur the image!
(Image credit: retrieved from Isa Garcia's blog.)
Just like a fun house mirror distorts normal images, the right fun house mirror can fix distorted images, if you create just the right mirror. But if you can create the proper mirror to fix the guide star (i.e., the light from the laser), you can also fix the light from your observing targets! Creating a system that continuously adapts its mirror to the changing atmosphere, giving you an undistorted image of your observing target at the end, is the end-all goal of adaptive optics.
(Video credit: 3 minute visualization of an AO system, by Gemini Observatory.)
And when this is put into practice, adaptive optics is capable of taking what looks like turbulent, nonsense noise and turning it into a crystal-clear, real-time image of what actually lies out there in the Universe.
Want to see it in action? Take a look at this 2006 video of adaptive optics taking on a binary star system; you seriously won't believe it.
(Movie Credit: Guido Brusa, CAAO, Steward Observatory.)
That was then.
Just a couple of months ago, Gemini South Observatory released their first light image from GeMS/GSAOI, the world's most advanced adaptive optics system, attached to the 8-meter Gemini Telescope. And wouldn't you know which object they happened to take a look at for their very first image?
(Image credit: Gemini Observatory / NSF / AURA / CONICYT / GeMS/GSAOI.)
Wouldn't you know: it's globular cluster NGC 288! As the GeMS Principal Investigator, François Rigaut was absolutely amazed at this image, and said,
We couldn't believe our eyes! The image of NGC 288 revealed thousands of pinpoint stars. Its resolution is Hubble-quality - and from the ground this is phenomenal. This is somewhat uncharted territory: no one has ever made images so large with such a high angular resolution.
Although all of that is true, I think University of Toronto Astronomer Roberto Abraham more encapsulated my reaction to this image, when he said,
This is fan-freaking-tastic!!!!!!! And it is! If you horizontally flip and (slightly) rotate the raw image, you can actually overlay it atop the Hubble image back at the top of the page, and compare these two directly!
At this zoomed-out resolution, it doesn't look all that impressive, especially considering the monochrome nature of the ground-based image.
But let's take a look at a very small region -- those four bright horizontal stars towards the center of the above image -- with both the Hubble Space Telescope and the Gemini telescope with the new adaptive optics!
Even at first light -- with its very first image -- the GeMS/GSAOI adaptive optics were easily just as good as Hubble's resolution, the first time that a ground-based telescope has ever done that!
Of course, that was like, two months ago already, so Gemini has since gone on to take even higher resolution images than Hubble can, like this one of NGC 2362.
(Image credit: Gemini Observatory / GeMS/GSAOI.)
Sorry that there's no Hubble image of this to compare with, only a Spitzer image that really looks like a joke, particularly next to the full-resolution Gemini version. When you're looking at the image above, remember that each quadrant is less than one ten-thousandth of a square degree! Highest. Resolution. Image. Ever.
And that's how you defeat Hubble without ever leaving the ground!Read the comments on this post...
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The University of Puerto Rico at Arecibo has a very interesting facility that has put out some fun stuff
And I suspect he's done so willingly. Well, you know what they say about statistics and liars.
Here's the story. The Wall Street Journal and the Daily Mail independently published highly misleading and blatantly idiotic pieces on climate change. We've covered this extensively already over the last few days. Phil Plait, of the Bad Astronomy Blog on Discovermagazine.com, was one of numerous scientists to respond to those flaming examples of horrific bottom feeding journalism with the post "While temperatures rise, denialists reach lower." In that post, he presented a still-image from a moving GIF that has been going around, originally from Skeptical Science. I've used the GIF myself just recently, but I'll re-post it here for your convenience:Read the rest of this post... | Read the comments on this post...
Come the Festival to Hear Featured Author Theodore Gray! [USA Science and Engineering Festival: The Blog]
"The periodic table is the universal catalog of everything you can drop on your foot"
You have the amazing opportunity to hear from best-selling author Theodore Gray at this year's USA Science and Engineering Festival Book Fair! Gray will be speaking at the Teen Non-Fiction Festival Stage at 11:50 am on Saturday, April 28th. His newest book is Theodore Gray's Elements Vault: Treasures of the Periodic Table with Removable Archival Documents and Real Element Samples - Including Pure Gold! Gray's other books, The Elements and Mad Science, are international bestsellers, as is the wildly popular The Elements for iPadebook.
Theodore Gray's Elements Vault picks up where The Elements left off. Organized into the nine major groups of the periodic table, including the alkali metals, the alkali earth metals, the transition metals, the nonmetals, the metalloids, the halogens, the noble gases, the actinides, and the lanthanides, Elements Vault includes all new text, new photographs, and even more information about the elements.
Elements Vault also includes 20 removable historic documents related to the elements and the field of chemistry, such as Einstein's famous letter to Roosevelt explaining the potential of uranium for use in nuclear weapons, a genuine advertisement for lithium-laced 7UP soda, Mendeleev's original notes on the periodic table, and more. Each of these documents is individually packaged in an envelope attached to the book page. The document can be removed and handled and then put back into the book for safekeeping. Also included is a gorgeous 20″ x 10″ poster of the unique rainbow spectrum emitted by each element in the periodic table.
Along with all the information and fascinating facts about the elements, readers will discover the irresistible dry wit and humor of chemist and Popular Science contributor Theodore Gray. Cecil Adams, of "The Straight Dope" says, "Gray...has attained a level of near superhuman geekery that the rest of us can only mutely admire."
"Even if this book weren't absolutely gorgeous, it would still be a worthwhile investment because of how well it works as Coffee Table Education. This is when you leave a book lying around that is so tempting the kids pick it up and start learning stuff without even being asked! Delightful."
I'm using Dava Sobel's Longitude this week in my timekeeping class. The villain of the piece, as it were, is the Reverend Dr. Nevil Maskelyne, who promoted an astronomical method for finding longitude, and played a major role in delaying the payment to John Harrison for his marine chronometers. It's a good story, with lots of science and engineering and politicking.
There's one critical flaw, though, in terms of me teaching this book, which is that I don't really know how to say Maskelyne's name. And even Wikipedia is letting me down, here, by not providing a phonetic rendering of his name. Which means I'm depending on you, my wise and worldly readers, to help me figure this out:
Nobody had even begun to think about quantum physics during Maskelyne's lifetime, so you're only allowed to pick one answer, not a quantum superposition of multiple answers.Read the comments on this post...
Michael Mann, famous climate scientist, has released a book called The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (also available as a Kindle edition). I've not read it yet but I thought you'd like to know about it.
Michael Mann is the guy who came up with the Hockey Stick graph and metaphor. Early reviews are positive:In this meticulous and engaging brief on climate change research and the political backlash to legitimate scientific work, Penn State professor Mann narrates the fight against misinformation from the inside. (Publishers Weekly )
An important and disturbing account of the fossil-fuel industry's well-funded public-relations campaign to sow doubt about the validity of the science of climate change.
Kirkus (STARRED REVIEW)
If you don't believe our climate is changing, read this book. Dr. Mann will change your mind. For us, it's a war of words. Preserve the Earth, and pass the ammunition. (Bill Nye the Science Guy )Read the comments on this post...