April 29, 2015
If you want to gain a good understanding of how the Moon probably formed, you have to first understand the intricacies and limitations of “equations of state”, or EOS for short. An EOS is essentially a mathematical expression that tells you how the pressure of some material changes when other properties of that material also change. Those properties can be the density (how much of the material there is in a certain volume), the temperature (something we are all familiar with), or the internal energy.
The material from which the Moon formed was pretty exotic: it was a mixture of very hot magma (that is, molten rock) surrounded by quite hot rock vapor. Where did that stuff come from? It was going around the Earth right after our planet was smashed by another planet, shortly after the Earth had formed. The collision obliterated the planetary projectile, and gave the Earth a pretty big dent. Most of the Earth’s surface was melted by the blow, and about two-Moons’ worth of hot liquid and vapor was sent into Earth orbit. The Moon would form from that stuff shortly afterwards.
The thing is that the Moon-forming debris was composed of different rock materials, and so describing its thermodynamic behavior (that is, how its pressure changed with temperature or density) is not so easy. But there are several EOS out there that have been used by scientists to study how the planetary debris behaved, mainly through computer simulations. It’s both a fascinating and challenging tale of thermal physics, and I’m in the process of writing it clearly and concisely.
(Video by Canup 2012)
April 23, 2015
In case you haven’t heard, a science-fiction movie called The Martian will come out in November. It’s based (supposedly) on a novel of the same title written by engineer Andy Weir. I was introduced to the book by my friend Chris, and when I read the first line, I was instantly hooked. It ranks as one of my favorite hard sci-fi books.
Most of the story is told by “the Martian” himself, an astronaut that gets stranded on Mars after his crewmates are forced to leave him there, due to an emergency. He is then forced to apply every last bit of ingenuity to stay alive, in the hopes that someone will try to rescue him.
What I liked about the book is that it’s a story of survival, reliance and hope, but from the point of view of a professional who is more interested in doing everything that he can to stay alive than in lamenting that he might not see anybody else ever again. He doesn’t appeal to his emotions to find strength, but rather he appeals to his scientific and engineering skills, as well as his astronaut training, to contact anyone who might hear (or see) him.
I wonder if they’ll make the book mandatory reading for astronauts.
April 19, 2015
Lunar and Planetary Institute
June 5th is the deadline to submit a grant proposal for NASA’s “Emerging Worlds” program. I’m currently working on the Scientific/Technical/Management section, which is the main component of the proposal. It has a 15-page limit, including figures. I won’t give away what the proposal is on exactly, but suffice it to say that the background material that I’m currently writing deals with the formation of the Moon!
March 21, 2015
If you are a space geek like me, you’ll enjoy this video of space shuttle Columbia mission STS-64 shot from the cockpit, with internal communications. Watch especially around the 12-minute mark, when the main engines are shut off.
March 13, 2015
Were Christopher Columbus’ voyages analogous to an eventual trip to Mars? In this very engaging blog post, the author argues they were. The discussion at the bottom is quite interesting too.
March 1, 2015
An amazing computer visualization by the Discovery Channel (reported here by IFL Science) shows the damage caused by an impact of a 500-km asteroid with our fragile Earth. Basically, many things would fry. An ocean of magma (melted rock) would be created. Hot debris would rain down thousands of kilometers from the impact site. School would probably be cancelled.
Be sure to also check out the link to the impact calculator mentioned at the end of the IFL Science post. It tells you what would happen in the event of collisions with different parameters, such as impactor size, velocity, composition, etc.
February 26, 2015
Only 20 more days till the Lunar and Planetary Science Conference (LPSC) begins! This is a venerable gathering of scientists who study the geology, geochemistry, and astrophysical aspects of solar system objects. It promises to be an exciting event to learn the latest in lunar research, hear about the latest results from the Mars Curiosity rover, and feast on the amazing science being delivered by the Rosetta space probe currently in orbit around a comet! I’ll be blogging from the Conference.