Category: Space

A Moon With a View

By Julianne Dalcanton | December 13, 2012 3:34 pm

This weekend the Seattle Times published a lovely interview with Bill Anders, one of the Apollo astronauts.  The article is full of interesting little tidbits, but I was most taken with his description of taking photos while his capsule orbited the moon:

While he had been meticulously trained to photograph the moon, making pretty pictures of the Earth from space had not occurred to anyone at NASA. So Anders, with no light meter and really no idea where to start, improvised.

“I had to bracket (the exposure),” he says. “I’m just going click-click-click-click-click, just changing that f-stop up and back. I machine-gunned that mother.”

The resulting picture was one of the most famous from the Apollo program — the classic NASA “Earthshine” photo.  Which, the article reveals, has actually been “printed backwards for more than 40 years because of a NASA mistake”.

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CATEGORIZED UNDER: Space, Uncategorized

Eyes on Andromeda

By Julianne Dalcanton | December 11, 2012 4:30 am

The practice of astronomy is different than it used to be.

Back in the day, the image was of the lone astronomer, sitting at their telescope, communing with the universe.  Over time, we got more use to the idea that maybe groups of astronomers might come together to work on a common project.  But still, there were fairly tight connections between astronomers and their data.

Over the last decade and a half, something fundamental has changed.  Data has gotten big. So big, that it’s impossible for any one person to make sense of it.  More importantly, data of these sizes make it impossible to “notice” anything.  The line of research that probably got me tenured was based on “noticing” something interesting in several dozen galaxies.  But how do you “notice” something in hundreds of terabytes of data?

The standard answer these days is (naturally) computers.  Computer science is great at problems like this, and many astronomers are working on the interface of CS these days.  But that said, there are some problems that software is simply lousy at.  So what do you do when your scientific interests run smack into a problem that you can’t code your way out of?

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CATEGORIZED UNDER: Science, Science and Society, Space


By Julianne Dalcanton | October 4, 2012 10:23 pm

If you’ve ever spent much time around astronomers, you’ll know that they tend to like their theme wear — space ties, galaxy t-shirts, satellite lapel pins, etc.

To this list, I am thrilled beyond measure to add space clogs. Yes, space clogs. Dansko has come out with a limited edition “Stargazer” version of their standard “Professional” line clog, and I was compelled to pre-order them because… well… they’re space clogs.

They just arrived today, and they’re even more magnificent that I’d hoped.  Not only do they have an extremely realistic star field on them (with diffraction spikes and everything), but the left shoe even hosts a young stellar cluster near the toe (click on the image for a better look).  Besides being simply AWESOME, young stellar clusters are something that members of my research team are studying right now. In short, we are currently analyzing data that looks like my shoes.

(PS. Gotta give a shout out to Jerry at Little’s Shoes in Pittsburgh, who helped make this possible!)

CATEGORIZED UNDER: Miscellany, Space

NASA Gets a Present

By Julianne Dalcanton | June 4, 2012 10:34 am

The exciting news of the day is that the “National Reconnaissance Office” is donating two unused spy satellites to NASA.  From the limited information available, there are two satellites with 2.4 meter  mirrors just sitting around gathering dust (metaphorically speaking, because they’re actually parked in a climactically controlled clean room). There are no instruments on board, and they lack solar panels or pointing controls, so it will take a fair bit of engineering to turn these into upward-looking space telescopes. In the real world, “engineering” is the same thing as “money”, so the exact fate of these satellites is not clear.  However, it is likely that one will be repurposed into “WFIRST”, which was the Frankenstein-style mission proposed by the latest astronomical decadal survey to provide further observational constraints on Dark Energy.  Many had wondered why no significant funding lines were opening up for WFIRST, but it seems likely that this has been the deep-background plan for a while.  However, WFIRST is only one mission, and there are two satellites, which opens up some exciting possibilities.  I’m sure the UV community in particular is starting to salivate — they’ve been making huge advances in coating and detector technology, so even a modest 2.4m mirror could offer as big a gain as the jump to the James Web Space Telescope (JWST) offers in the infrared.

As someone who spends a lot of time working with the Hubble Space Telescope, this is nothing but good news. The official lifespan of the Hubble is nominally over a few years from now, and the thought of losing generic optical-UV capabilities in space for a decade or more is horrifying.  I’m now much more optimistic that we’ll at least have something up there while we do the hard work of figuring out how to move past the 2.4m aperture size.

The other interesting bit in this for many is the fact that this gift is coming from what is known as the “dark side” — the area of technological development that scientists are not allowed to know about.  The same companies that build major space science facilities (Northrup-Grummond, Ball Aerospace, etc) also build facilities for the military and “reconnaissance” organizations.  The science and military efforts are kept heavily firewalled from each other, of course, but there is frequently a very abstract, high-level of cross talk between the two.  When you’re putting together a project, it becomes clear from the contractor which kinds of capabilities are “easy” (where “easy” means they know how to do it, because of requests from some other government entity).  It is therefore no coincidence that both the Hubble Space Telescope and these unused satellites share a 2.4m mirror, and you can pretty much be assured that some of the expertise used in building JWST either came from or is destined to pass through to the dark side.


CATEGORIZED UNDER: Science, Space, Technology
MORE ABOUT: space telescope

Deep Space GPS from Pulsars

By Mark Trodden | March 31, 2012 7:12 am

This semester I’m teaching General Relativity, and as part of discussing gravitational waves, this week I briefly discussed pulsars. It was quite timely therefore when I learned of a new proposal that pulsars may ultimately provide a perfect navigation system for spacecraft far from Earth.

Here on Earth, the Global Positioning System (GPS) gives us a highly accurate way of determining position, and many of us now use hand-held devices every day to help with directions. These work because GPS satellites provide a set of clocks, the relative timings of the signals from which can be translated into positions. This is, by the way, another place where both special and general relativity are crucial to how the system works. Out in deep space, of course, our clocks are unfortunately useless for this purpose, and the best we currently can do is by comparing the timing of signals as they are measured back on Earth by different detectors. But the accuracy of this method is limited, since the Earth is a finite size, and our terrestrial detectors can therefore only be separated by a relatively small amount. The further away a spacecraft is, the worse this method is.

What Werner Becker of the Max-Planck Institute for Extraterrestrial Physics in Garching has realized (and announced yesterday at the UK-Germany National Astronomy Meeting in Manchester), is that the universe comes equipped with its own set of exquisite clocks – pulsars – the timing of which can, in principle, be used to guide spacecraft in a similar way to how GPS is used here on Earth. Of course, it isn’t quite as simple as all that.

A significant obstacle to making this work today is that detecting signals from the pulsars requires X-ray detectors that are compact enough to be easily carried on spacecraft. However, it turns out the relevant technology is also needed by the next generation of X-ray telescopes, and should be ready in twenty years or so. Perhaps one day our spacecraft will map their routes through the cosmos thanks to yet another spinoff from basic research.


Space Launches Over Time

By Sean Carroll | October 11, 2011 9:15 am

Technology Review has temporarily made their archives openly available, and one of their recent features is this fascinating plot of the number of space launches over time. (Via FlowingData.) This is a cropped and shrunk version; see the original article for the full glory.

The authors offer an explanation for why the Soviet Union had so many more military launches in the 70’s and 80’s than the US did: their satellites tended not to last as long. I didn’t find a reason for the uptick and subsequent downturn in US commercial launches in the late 90’s.

There’s no danger that we’re going to stop going into space altogether, but we don’t go as often as we once did. We’ll probably need a phase transition of some sort to change that situation dramatically. That could be sparked by private companies, or if China lands someone on the Moon. (Not equally good reasons to re-commit to space, but reasons nonetheless.)


Hubble's Successor

By Risa Wechsler | September 6, 2011 5:34 am

My friend and colleague James Bullock, a professor at UC Irvine, has a great editorial up today in the LA Times about the next generation space telescope JWST. JWST is big. And it’s over budget, which makes it especially vulnerable in the current political climate. But it’s damn important. It’s a tool to inspire, a tool to help us write the story of the universe.

Walk through the halls of UC Irvine’s astronomy wing after dinner on a weeknight and you will find roomfuls of young graduate students, crammed into small desks, solving equations, writing computer code and developing innovative ways to analyze data. They do not have to be here. These are people with career options. They are scary-smart, creative and hardworking. Yet they have come here from all over the country and the world to sit in windowless offices and make a fifth of the money they could make back home or up the street. Why? They want to unlock the universe.

The United States is still the scientific light of the world. Ours is the society responsible for discovering humanity’s place in the universe, that we live in a galaxy called the Milky Way, one among billions of other galaxies stretched across the cosmic landscape. A hundred thousand years from now, if humans make it that long, the U.S. will be remembered for this, and historians will point to the immense contribution of the Hubble Space Telescope, with its miraculous visible-light images, the most detailed pictures of the cosmos yet produced by humankind.

Sadly, U.S. scientific leadership is beginning to fade. There is a sense of fear among our leaders that we can’t afford to invest in our future, just the kind of fear that endangers thoughtful debate about big-picture priorities.

One testament to our changing priorities is our commitment to the Hubble telescope as compared to its successor. The Hubble is, in every way, a monument to scientific exploration. Thanks to the Hubble, orbiting 350 miles overhead, we know that the universe began just under 14 billion years go. The age of the cosmos, once believed to be unknowable, is now available at the click of a mouse and has made it into schoolbooks in all 50 states. Astronomers have used the Hubble to determine the chemical makeup of planets that orbit distant stars and to discover dark energy, a mysterious substance propelling the universe to expand at an accelerating rate.

Many of the graduate students filling astronomy departments at University of California campuses, as well as Caltech and Stanford, have come to the state to explore and analyze terabytes of Hubble data. These data involve complex digital images, created in raw form onboard the orbiting telescope, and then decomposed into precise component colors. The Hubble beams this information to receivers around the world, where it is processed and made available for download. A graduate student working in Irvine can transfer Hubble images to a computer and then develop software to process and analyze the images’ meaning.

The goal is to squeeze information out of the gathered light that will help us discern the size, structure and chemical composition of objects that are almost always too far away for humans to ever hope to visit. The people who do this work are both creative and technically gifted. They must take what the universe provides — a shred of light collected by the Hubble — and discern implication from its signal.
We want these intelligent, dedicated people to live in our cities, to make their discoveries at our universities and to raise their families — the next generation of bright minds — right here.

Read the whole thing here. And then write your Senators and Representatives. JWST, and with it, US scientific leadership, and an amazing opportunity to fill in the contours of the history and physics of our Universe, is really at risk. Very possibly only an outcry of the kind that saved Hubble will be enough to launch Hubble’s successor.


Water on Mars

By Sean Carroll | August 4, 2011 12:13 pm

Here’s a pretty picture from JPL, based on data from NASA’s Mars Reconnaissance Orbiter. Click to see a larger version. (Note that the image is highly doctored, in the best NASA tradition; not just false-color, but they’ve “reprojected” so that a satellite image now looks like it was taken by a flying helicopter!)

Water on Mars” is one of those things (like “black holes” or “the missing link”) that seems to be discovered over and over again. That’s because we’re not really finally discovering it once and for all; we’re slowly gathering new evidence, and also evidence for different manifestations. It seems clear that frozen water exists in the polar regions of Mars; also, there’s good reason to think that there used to be running water at some point. This new finding would be evidence for running water right now.

In this case, NASA scientists have noticed seasonal changes in hillside patterns such as this one. The dark streaks seen in the image appear in the spring and summer, then fade again in winter. (Kind of like the Los Angels River, but backwards.) The best idea we have for an explanation is running water. Not that the darkness is water itself, but some change in the underlying substance as a result of water. It’s a very good idea — likely true — but still not quite like we’ve filled up a cup and done a chemical analysis.

Anything with any tenuous connection to “life on other planets” runs the risk that everyone wants it to exist and is looking very hard; consequently, skepticism is always warranted. Still: awesome pictures!

CATEGORIZED UNDER: Science, Space, Top Posts

NASA Astrophysics: It Really Is This Bad

By Sean Carroll | July 20, 2011 10:38 am

Shorter House of Representatives: NASA shouldn’t do astrophysics anymore. Via the Tracker, an article by Eric Hand in Nature News that puts the fiasco in helpful graphical form.

Misleading graphic alert! The vertical scale starts at $0.5 billion, not at $0. But taking that into account merely changes the situation from “complete annihilation” to “devastating harm.” We’re talking about a 40% cut, which won’t leave room to do much more than keep the lights on for existing programs.

The 2011 numbers are the President’s budget request; the 2012 numbers are from the bill that passed the House. This isn’t yet law, so there’s still time; the Senate and the White House will (thankfully) be involved in the final compromise.

Times are tough, and not everything is worth doing. But there are few things more important to the long-term flourishing of a country than investment in basic science. Sad to see the future sacrificed for bizarre political reasons.

CATEGORIZED UNDER: Science and Politics, Space, Top Posts


By Daniel Holz | July 8, 2011 8:23 am

While the astronomy community reels from the potential loss of the James Webb Space Telescope (see Julianne and Risa’s posts), it is appropriate that we also mark the passing of the Space Shuttle program. All being well, in about 15 minutes the last space shuttle will rocket into space (live video).

The space shuttle program was essential to the launch, and perhaps even more importantly, the multiple repairs of the Hubble Space Telescope. And it is the inevitable loss of the Hubble, and the absence of a worthy successor in space, that is leaving the astronomy community despondent.

These are difficult financial times. Brutal decisions need to be made. It is certainly conceivable that the United States (and the world) simply can no longer afford to finish off the James Webb Space Telescope. However, it is worth noting that this telescope in many ways symbolizes the best aspects of humanity: our thirst for knowledge, our desire for exploration, and our quest to find our place in the Universe. There is a reason that the Hubble space telescope captures the imagination of both practicing scientists and the general public. We cannot help but be moved and fascinated by images of the cosmos. Have we truly come to a point where we abandon this most noble and inspirational of pursuits?


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