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No more driving for Spirit

26 Jan

Artist's rendering of Spirit; Courtesy: NASA/JPL-Caltech

It’s the end of an era. The rover team has decided to leave Spirit where she is. Other than getting the solar panels in better position to catch sunlight, the rover will become a stationary science center.

This morning, the NY Times had a story that didn’t sound particularly optimistic. But this afternoon, the rover team made the official announcement.

Spirit might still have interesting science to report. And, oh, yeah, Opportunity is still driving.

Practical phase changes: more carbon dioxide

9 Dec

I get to talk about an interesting application of carbon dioxide today in my latest article for Scientific American: sterilizing transplanted tissues such as tendon and bone. Before I heard about this technology, I certainly wouldn’t have suspected that the ubiquitous gas that we exhale could become a super-scrubber with a little heat and a lot of pressure.

I’ve ended up playing with a lot of carbon dioxide over the years. Like most kids, I had ghoulish carbon dioxide bubbles from dry ice that fizzed my Halloween drinks. As a chemist, dry ice became almost too “normal.” As an undergrad, I made my own bricks of the stuff from a tank of compressed CO2, and in graduate school, I’d weigh it out by the tens, if not hundreds, of pounds. Mostly, I used it to cool things down.

But though it’s easy as a working organic chemist to think  it cliché, watching the supercritical fluid form and dissipate is amazing. That sense of wonder within a high pressure chamber– and the practical applications that come from it– keep me coming back to work everyday.

Speaking of clichés, this professor probably fits the stereotypical scientist image a little too well. But I love his giddy enthusiasm when he talks about how he uses the demonstration to see whether a prospective student might be a good fit for his research group.


Hubble: still amazing after all these years

10 Sep
NGC 6302 (Butterfly Nebula, Bug Nebula) Credit: NASA, ESA, and the Hubble SM4 ERO Team

NGC 6302 (Butterfly Nebula, Bug Nebula) Credit: NASA, ESA, and the Hubble SM4 ERO Team

I love big, beautiful Hubble pictures, and these most recent ones are no exception. When I was working on the new astronomy exhibits at Griffith Observatory a few years ago, I marveled that I got paid to dig up spectacular images like this one. In a time where basic science rarely makes the local evening news, even these photos got a mention on the 11 pm news last night.

But though I’m awed by the pretty pictures, I’m also amazed that a nearly 20-year-old telescope continues to churn out amazing science and that NASA had the wisdom to continue to service such an incredible eyepiece into the universe. Somehow it generally seems easier to build something new without seeing potential in  a tune-up for an older instrument. (And– just to be clear– I’m not saying that we shouldn’t build the Hubble’s successor, the James Webb Space Telescope— no relation to Webb of Science, BTW, though no quarrels with sharing a very good name).

I guess the Hubble is also reminding me how valuable refurbishing something old, but made with quality– like a well-made piece of furniture or the Birkenstock sandals I’ve worn to death over the past 4 summers– can be in the long run.

Revisiting DNA origami

1 Sep

Creating a genetic program to crinkle DNA into the perfect shape can appear to be a scientific stunt. But DNA origami is more than a molecular magic trick. In this excerpt from a 2007 TED lecture, Paul Rothemund describes the science behind the work– how a chain– based on its sequence– becomes a two-dimensional shape.

But this work isn’t all fun and smiley-faces– as an article in today’s New York Times about tiny transistors points out:

I.B.M. is also exploring higher-risk ideas like “DNA origami,” a process developed by Paul W. K. Rothemund, a computer scientist at the California Institute of Technology.

The technique involves creating arbitrary two- and three-dimensional shapes by controlling the folding of a long single strand of viral DNA with multiple smaller “staple” strands. It is possible to form everything from nanometer-scale triangles and squares to more elaborate shapes like smiley faces and a rough map of North America. That could one day lead to an application in which such DNA shapes could be used to create a scaffolding just as wooden molds are now used to create concrete structures. The DNA shapes, for example, could be used to more precisely locate the gold nanoparticles that would then be used to grow nanowires. The DNA would be used only to align the circuits and would be destroyed by the high temperatures used by the chip-making processes.

The DNA transistor mold– what a cool nanoscale idea: build the shape, pour your circuit and destroy the mold when you’re done.

P.S.: my earlier origami post from May– in case you missed it.

Melodies divert droplets

26 Aug

So, today I’m revealing some the depths of my true chemistry geekiness. As I was poring over press releases, I found one from the University of Michigan that was fun– but probably also too geeky– to propose as a story idea: a microfluidic device that moves droplets based on sound waves.

First of all, some explanation: Microfluidic devices are tiny networks of channels that chemists and chemical engineers are building as ways to mix and recombine a variety of chemicals. One of these days this technology will probably run all sorts of diagnostic devices– the sorts of gizmos that might sequence your DNA and scan your system for all sorts of diseases by splitting up a tiny drop of your blood.

However, part of the problem with these devices, as the University of Michigan researchers note, is that though the systems of channels are often tiny, the devices that you hook to them to move the droplets around often aren’t. So they built a system that would move the drops that alter how the droplets move based on sound frequencies. So, the melody choreographs the droplet movement.

I guess it could make for a noisy lab, but, geek that I am, I can’t help but enjoy the video of the droplet dance.

a microfluidic device (Micronit Microfluidics)

a microfluidic device (Micronit Microfluidics)

More Mars Rovers

27 May

The rovers are still my favorite NASA mission, for reasons I’ve already written about. Even if the rovers quit tomorrow, the rover science team of Steve Squyres of Cornell and company would still have decades of data to comb through and analyze. Last Friday, they published more of the Opportunity data in the journal Science (requires subscription) that documents the role that salty, acidic water and wind have played in sculpting the magnificent rock formations in the craters of Meridiani Planum.

Cape St Vincent explored by Opportunity in Victoria Crater, Courtesy of NASA/JPL-Caltech/Cornell

Cape St Vincent explored by Opportunity in Victoria Crater, Courtesy of NASA/JPL-Caltech/Cornell

Spirit stuck in the sand, Courtesy of NASA/JPL-Caltech

Spirit stuck in the sand, Courtesy of NASA/JPL-Caltech

But I still have my soft spot for Spirit, even though that robot is stuck in the sand with another gimpy wheel. The pictures from rover missions are amazing, the science is spectacular, but I’m still floored by the engineering and troubleshooting involved in maneuvering a robot in a harsh environment on a planet 100 million miles away. The mission engineers have managed these problems remotely for more than 5 years– I know my car would need a hand-on tune-up long before that.

That’s not to say that there isn’t hands-on testing involved, and apparently, those steps are underway on the ground at NASA’s Jet Propulsion Laboratory to find a way out of the sand.

Work at the Jet Propulsion Laboratory to find a way out for Spirit, Courtesy of NASA/JPL-Caltech

Work at the Jet Propulsion Laboratory to find a way out for Spirit, Courtesy of NASA/JPL-Caltech

I’m not a gambling woman, but my (Monopoly) money is on the rover and the engineers.

Check out these news reports for more details:

The New York Times article from May 25

And an article by the San Francisco Chronicle‘s veteran science reporter, David Perlman

Hubble mania

18 May

The repair of the Hubble telescope has been big NASA news, but I’m impressed with the way it’s been covered in the Twitterverse through spacewalk updates, astronaut tweets in orbit, and general chatter.

Hubble telescope, credit: NASA, STScI

Hubble telescope, credit: NASA, STScI

NASA has always had a great website and tends to go the extra mile to communicate what’s going on with the public. As a science journalist, I’ve found that they’re one of the easiest government agencies to work with: they tend to be really good about putting you in touch with scientists who are excited to talk about their work.

But in scanning the NASA twitter feeds today, I was particularly impressed by what twitter brings to the table in terms of public engagement and understanding of science. Here’s an exchange between @NASA and @sweetgreatmom:

@NASA What is the purpose for the thermal blanket?

@sweetgreatmom The blankets protect Hubble against solar degradation and space debris.

Curiosity and public engagement are essential to keeping science important in society. Though I don’t always know exactly what to do with Twitter myself, I’m delighted that it mediates this kind of communication between everyday people (taxpayers who fund this exploration) and the people who carry it out.

@NASA also quotes John Grunsfeld today, one of the astronauts who completed the final spacewalk to repair Hubble today: “Hubble isn’t just a satellite- it’s about humanity’s quest for knowledge.” It’s great that we all get to participate.

Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration

Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration