Archive for February, 2011
From Today I Found Out:
The beam itself measured 2000 gray as it entered Bugorski’s skull and about 3000 gray when it exited on the other side. A “gray” is an SI unit of energy absorbed from ionizing radiation. One gray is equal to the absorption of one joule of radiation energy by one kilogram of matter. An example where this is commonly used is in X-rays. For reference, absorption of over 5 grays at any time usually leads to death within 14 days. However, no one before had ever experienced radiation in the form of a proton beam moving at about the speed of light.
I’m posting this out because it immediately made me think of the interview we did with Dr. DiRuggiero for last week’s 365 Days of Astronomy podcast:
The organism we’re working on at the moment is Halobacterium. They’re fairly resistant to radiation. We measure the resistance to radiation as the D10, which corresponds to the radiation doses for which 10% of a population survive. So the D10 of the organism, that is called the wild type. The regular organism is five kilo Gray—that’s measured radioactivity—which is pretty high. This is 5000 Gray, and humans are killed by five Gray. Those survive 5000 Gray; humans died with five Grays.
From Discovery News:
There are at least 50 billion exoplanets in our galaxy. What’s more, astronomers estimate that 500 million of these alien worlds are probably sitting inside the habitable zones of their parent stars.
As mentioned on the email list, this year we’re attempting to do a little astrobiology public outreach and education. Our first series of efforts are interviews with faculty and researchers here at Johns Hopkins who are actively involved in astrobiology-related research. These interviews will be featured on the once-a-day podcast site, 365 Days Of Astronomy. We’ve done two interviews so far, and the first one goes live on that site tomorrow. It’s an abridged, 12-minute version of our discussion with Dr. Jocelyne DiRuggiero of the Biology department about her research with halobacterium and hyperthermophiles, extremophiles that live in high salt and high temperature regions, respectively. Below I’m attaching the full, 24-minute interview as well as the transcript.
Let us know, either through the comments section below or on the email list, if you’re interested in helping out by suggesting someone to interview, being interviewed yourself, or anything else you’re interested in trying (it’d be nice if we had a theme song….). Our next interview is with Dr. Naomi Levin of the Earth & Planetary Science department. It should be going up in the next month and will be featured on 365 Days Of Astronomy in April.
Now, on with the podcast!
With the Kepler Mission’s discovery of 4 potential Earth-sized planets orbiting in their host star’s habitability zones, the main question about life is no longer “Is there life out there somewhere?” Instead we must ask, “Exactly what sort of life could exist on these strange planets?” For today’s 365 Days Of Astronomy podcast, the JHU Astrobiology Forum’s Adam Fuller begin answering this question by speaking with Dr. Jocelyne DiRuggiero, an associate research professor in the Biology department at Johns Hopkins University, about her research with microorganisms here on Earth that live in environments so hellacious, they could easily be thought to be from another world.
I get forwarded stuff. A forward I got today is for a week-old BoingBoing post about Greg Laughlin’s “exoplanet valuation” equation. Laughlin is essentially trying to find a way to quantitatively compare the importance of each exoplanet discovery. In this case, he’s trying to put it in terms of dollars and cents. I don’t see where on his site he does the derivation for the equation, and I haven’t tried running any of the numbers yet (I’m still looking for a complete list of all 1200 new candidates), but the BoingBoing post says that so far:
At the time, the exoplanet Gliese 581 c was thought to be the most Earth-like world known beyond our solar system. The equation said it was worth a measly $160. Mars fared better, priced at $14,000. And Earth? Our planet’s value emerged as nearly 5 quadrillion dollars. That’s about 100 times Earth’s yearly GDP, and perhaps, Laughlin thought, not a bad ballpark estimate for the total economic value of our world and the technological civilization it supports.
The BoingBoing link breaks down the equation, but you can find Laughlin using it everywhere on his blog.
This Friday, February 4, 2011, at 12:30pm in John Bahcall Auditorium at the STScI, Dr. Vikki Meadows from University of Washington will give the next Planets, Life, and the Universe Astrobiology Lecture. The title of her talk will be “The Virtual Planetary Laboratory: Modeling Signs of Habitability and Life on Extrasolar Planets.” Here are the details:
In the coming decades, the search for life outside our Solar System will be undertaken using astronomical observations of extrasolar terrestrial planets. To better inform our search, the NASA Astrobiology Institute’s Virtual Planetary Laboratory team uses a suite of computer models to explore the interaction between a terrestrial planet and its parent star. The resulting models allow us to simulate extrasolar terrestrial planetary environments and spectra, and to define and quantify likely signs of planetary habitability and life. This talk will discuss the VPL models and results to date, including the detectability of planetary habitability and potential signs of life from alternative biospheres.