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Microlensing Uncovers Earth-Like Planet
smooth wombat writes "Using a new technique called gravitational microlensing, a team of astronomers have discovered the smallest Earth-like planet circling a star 20,000 light years away in the constellation Sagittarius. Unfortunately the planet takes ten years to circle the red dwarf and has a surface temperature estimated at -220 C which means it's just a larger version of Pluto so the chance of finding life on this planet is essentially zero."
Unlike all the gas-giant, Jupiter-like planets we've seen so far. It's very difficult to spot tiny, Earth-sized objects from so far away. We may not find this new planet very hospitable but it's still an important discovery.
Until now.. they hadn't found a planet in another star system that was
A) terrestrial (solid, with a rocky surface) B) farther than 0.15 AU from its star.
This planet is 2.5 AU from it's star and it is not a gas giant. That's what makes it "earth-like".. in the way that mercury, venus, mars, and pluto are "earth-like".
Until now.. no such planet had been observed in another star system.
All of this is in TFA.
"I have as much authority as the pope, I just
don't have as many people who believe it" - George Carlin
Sugar doesn't melt?!?
I've made hundreds of kilos of candy from melted sugar.
It melts just fine and solidifies just fine
...Proxima Centauri is our neighbour and humans only recently diverged from the other apes. Earth-like is really just a literal translation of the Latin elements of the technically correct word which is "terrestrial".
-- SIGFPE
Since I am related to the guy interviewed for the ESO Press Release I feel obliged to link to it.
0 3-06.html
:)
http://www.eso.org/outreach/press-rel/pr-2006/pr-
I have not read the BBC article. But this is the official PR document. It's nice having relatives in the field. I had this news days ago.
----------------- Oink. Moo. rarr! -----------------
Uh, melting point varies with pressure and a couple other factors that depend on your PVT model. You can melt pretty much any material if you set the conditions correctly, regardless of wether the decomposition temperature is below the MP at 1 atm or not. The liquid phase may not be very accessible, but it's always there.
Also, you need a better example, since Sucrose (the molecule people mean when they say 'sugar' without a qualifier) has a MP of 191 degrees centigrade at 1 atm, i.e. it has a viable liquid phase pre-decomposition. Perhaps you're thinking of Glucose or Ribose?
You could make an argument that 'frozen liquid' would refer to an amorphous (non-crystalline/glassy) structured solid only, as these result from a skipping of the phase formation bit of solidification to just lock the structure of the liquid into solid form. However, I think it's more likely that the writers of the article just skipped the materials phase of their education, locking the structure of their brains into a void-filled physics-oriented glass. Or they just, you know, made the intellectual equivalent of a typo. Whichever.
...it's really a sad day for America when we require a goddamn ACT OF CONGRESS to make our DVD players work properly. ~
That being said, life depends on a certain level of chemical activity (I.E no thinking rocks) and a large degree of predictable organization (I.E. no intelligent vapor). Anything else requires repealing the laws of physics and chemistry as they currently understood. (The former is possible on the cosmic and subatomic scale, I.E. outside the realms of life. The latter is unlikely in the extreme.)
It takes ten years for the planet to orbit its parent star, a common-or-garden red dwarf that lies about 28,000 light years from Earth, close to the centre of our Galaxy. P.S. I submitted this news today at 4 a.m. : 2006-01-25 04:10:30 Discovery of the smallest yet Earth-like planet (Science,Space) (rejected)
http://arxiv.org/PS_cache/astro-ph/pdf/0505/0505 451.pdf (microlensing "jovian" events)
x ?type=oddlyEnoughNews (Jacks/Ch/Bahr)
t ml (OGLE Early Warning System)
http://bulge.astro.princeton.edu/~ogle/ (OGLE - Optical Gravitational Lensing Experiment)
http://today.reuters.co.uk/news/newsChannel.asp
http://www.astrouw.edu.pl/~ogle/ogle3/ews/ews.h
Not exactly
This is a really neat demonstration of the power of microlensing for planet finding. Though it's not the first, nor even the second, planet to be found this way (see for example http://xxx.lanl.gov/abs/astro-ph/0505451 and http://xxx.lanl.gov/abs/astro-ph/0505451), it really does show how microlensing can find small planets pretty far away from their host stars. It'll be a very good technique for determining the frequency of planets as small as the Earth. As for finding life on the microlensing discovered planets (using the future Terrestrial Planet Finder mission [http://planetquest.jpl.nasa.gov/TPF/tpf_index.cfm ] for example to search for biosignatures in their spectra), it'll be very difficult. The majority of these planets are going to be very far away from us (where there is the highest probability of finding a lens) and, by selection, they're going to have a second bright star very close by on the sky that will be difficult to coronagraph out. The microlensing planets are really all going to be one-shot deals where you have no hope of following them up in the foreseeable future. I think planets found by transits (the upcoming Kepler mission [http://kepler.nasa.gov/]) or by astrometry (the upcoming Space Interferometry Mission [http://sim.jpl.nasa.gov/]) will be much better bets for searching for life.
The carbon-Silicon which are the only atoms allowing complex molecules is one aspect. Another is the fact that life seems to require a small liquid solvent molecule (Water on earth). Ammonia has been mooted as an alternative. That tends to limit the ranges quite a bit since there are just not that many of those.
There is another issue here. Life on earth seems to be foudn everywhere we look, but it is becoming clearer and clearer from genetic studies that all the forms have a common ancestor. Life on Earth can be divided into Eukaryotic and Prokaryotic cells. Aukarotes are all comlex multicellular life forms, prokaryotic cells do not form any serious complexity on earth.
All eukaryotic cells have mitchondria in them, and this is what allows life to be so diverse: The cells can generate essentially as much energy as they need because they have their own internal powerplants in them, which prokaryotes (bacteria) do not. That makes one hell of a difference. Plants also have Chloroplasts which photosynthesize which solve essentially the same problem of small cells that cannot gorw because they cannot generate enough energy to sustain themselves. Eukaryotes are typically 1000-100000 biggen than bacteria.
It is not commonly ccepted that Mitochondria and Choloplasts in cells used to be independent bacteria and that the first eukaryote developed as some kind of symbiotic relationship between two bacteria. Either a parasite that invaded a cell or a cell that ate another cell, we are not sure.
But the curious part is this: In the 4 billion year history of life on earth this happened only twice. Once with mitochondira and once with chloroplasts. Only those two symbiotic mergers survived to bring us the variety of life we know. Considering how often bacteria and other microorganisms engulf each other it means that a working combo must have been an extremely rare and unique event in evolution.
So while other planets may certainly harbour simple bacterial life it appears that complex life is very very difficult to achieve.
The dangers of excessive individualism are nothing compared to the oppressiveness of excessive collectivism