From RedOrbit and Science News Astronomers Discover Lightest Exoplanet Yet
Astronomers claim to have discovered an exoplanet that is the most similar to Earth in terms of mass than any previously discovered.
Found in the constellation Libra, the planet known as Gliese 581 represents about twice the mass of Earth.
Astronomers have previously identified some 300 exoplanets, but most are much larger than Earth.
“This is by far the smallest planet that’s ever been detected,” said Michael Mayor, from the Geneva Observatory, Switzerland.
“This is just one more step in the search for the twin of the Earth.
“At the beginning, we discovered Jupiter-like planets several hundred times the mass of the Earth; and now we have the sensitivity with new instruments to detect very small planets very close to that of the Earth,” he told BBC News.
Mayor worked alongside an international team of scientists who made the observation using the low-mass-exoplanet hunting device known as the HARPS spectrograph, which is attached to the 3.6 meter ESO telescope at La Silla, Chile.
“The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the ‘habitable zone’ – a region around the host star with the right conditions for water to be liquid on a planet’s surface,” Mayor said in a statement.
“With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet”, said co-author Xavier Bonfils from Grenoble Observatory.
Although the planet passes too close to its star for life to be possible, scientists claim that another planet in the system may be.
Previous observations using the HARPS showed that the host star was known to harbor a system with a Neptune-sized planet and two “super-Earths”.
Gliese 581 d was discovered two years ago with a mass of about seven times that of Earth. It orbits its parent star in 66.8 days, according to astronomers.
“Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” said team member Stephane Udry.
“‘d’ could even be covered by a large and deep ocean – it is the first serious ‘water world’ candidate,” she added.
Sophisticated modern technology allows astronomers to observe exoplanets by studying the tiny wobble in star motion. The discovery of low-mass red dwarf stars like Gliese 581 adds potential of finding other low-mass exoplanets in the habitable zones, scientists said.
“With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,” said Bonfils. “The hunt continues.”
“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 – the one around 51 Pegasi,” says Mayor. “The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years.”
The international team’s findings will be published in the journal Astronomy & Astrophysics.
From Science News:
“The object, a mere 20.5 light-years away, could be as tiny as 1.9 Earths and isn’t likely to exceed twice that amount.”
This diagram shows the position of the four planets in the Gliese 581 system. The newly found, innermost body is Gliese 581 e, the smallest exoplanet yet discovered. The habitable zone (blue region), where water could exist as a liquid, clearly includes the outermost planet, Gliese 581 d.
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Ray (20:00:31) :
No. A bully is someone who uses strength or power to intimidate. As true leaders have pointed out from the Roman Republic to Ronald Reagan: if you want peace, prepare for war.
Question: do you want peace?
Smokey (21:00:08) :
You will never get peace at the point of a gun.
Article on what makes a planet habitable, even talks about CO2 well it is new scientist they could not resist.
http://www.newscientist.com/article/mg20026831.600-why-the-universe-may-be-teeming-with-aliens.html
Another interesting space discovery in the news,
“Astronomers have detected two of the most complex carbon-rich molecules ever found in interstellar space.”
http://news.bbc.co.uk/2/hi/science/nature/8009014.stm
With the subject of politics having been raised (USA), I guess we will see this thread degenerate rather quickly…. 🙁
..two of the most complex carbon-rich molecules ever found in interstellar space
So carbon’s not all bad, then!
The item was reported on the front page of The Guardian (famous for its spelling mistakes) as containing an important link to ‘animo’ acids. It’s not surprising that their science reporting is so uncritical when they can’t even pick that up…
Leon Brozyna:-)
“Intelligent Life”? Well, derrrrr! Intelligence is just one part of human existence, but it is pretty useless if not applied to anythin, & enhanced with the power of rational thought, a small mearure of aggression, a good deal of compassion & understanding, & a willingness to expore outside the cave! The third rock from our sun (great show) has an abudance of “intelligent life”, however, it is largely endowed with irrational thought, complacency, & a lack of adventure.
I suspect that there is oodles of extra-terrestrial life out there quite nearby, but they are using some form of disruption shield to prevent our “sensors” from detecting them, simply because they’ve seen & heard the double-act of Gore & Hansen, the UN, the IPCC, the EU, & said to themselves, “Just as we thought, no intelligent life there then!
Robert Wood;-)
Don’t worry, it’s hip to be cool when you’re hot! or is it hot to be cool when you’re hip?
Ray,
Who that waves the white flag like yourself ends up getting peace? People like you throughout history end up pushed out of your land, or turned into a slave.
You can only stop a bully by beating up the bully. If you can’t beat up the bully then you will always be his servant. Your boy Darwin taught us this, ‘survival of the fittest.
You are either Poland or Germany in 1938
You are either the Native Americans or the Europeans in the 17th Century
etc.
Seems like you prefer to be on the side that gets destroyed. Please do not be our leader when we meet another life form face to face. You will lead us to defeat.
I would think that, assuming the same density, the gravity at the surface of a planet would be proportional to the radius. The volume (and therefore mass) varies as the cube of the radius, and the inverse effect varies as the square of the radius. The power of R would then be 3 minus 2, which is 1.
I calculate that the gravity would be 4*PI*K*R/3/G where K is the density, R radius and G the gravitational constant.
Chris
I always, always feel a chill down my spine everytime someone mentions “Gliese 581”, and this is why.
I do not belive UFO are extraterrestial beings, I do look at those books about UFO as amusing (I haven’t read one in well over 20 years), and also as some pathetic stuff… except when I read something about Gliese 581 and habitable zones and planets the size of earth, etc.
And this is why: taking Roger pielkes take on “what would have to happen to make you change your mind”, my was finding a earthlike planet in Gliese 581!
I always remember this star because one of those stories on one of those bookes about abuducties (it stood in my imagination as I was growing up) was about an alien abuction and under hypnosis and all that crap in the stories the blablabla investigators draw what the person was descrbibing and it what was the star they told that person they came from?… YEs Gliese 581 !!!!
Here’s another thought about CO2 and the Gliesians.
CO2 is transparent to visible light and absorbs in four bands in the infrared. A Gliese planet in the Goldilocks zone (not too hot, not too cold, just right) will be getting roughly the same TSI as earth, but downshifted, with more of the energy in the CO2 capture bands than earth gets. CO2 would be much more of a ghg there than on earth.
Our eyes are adapted to the sun’s main energy band. Gliesians’ eyes would be adapted more toward the infrared, which would make CO2 a visible component of their atmosphere.
OLympus Mons,
It would really be neat if you could find that book.
Mike
“Ray (22:37:40) :
You will never get peace at the point of a gun.”
Hmmmm what have we been enjoying for the last 60 years with Germany and Japan?
When the bully at school hit me in second grade, I doubled him over with a lucky punch to his solar plexus… We were great friends from that moment til I lost track of him five years later… Ray Mould are you out there??
Great topic for this excellent science blog.
Readers should follow the recently launched Kepler mission. Its telescope stares at the Lyra-Cygnus region of our Milky Way galaxy for the next several years detecting the very faint winks as the 2% or so of planets in the same plane as us transit their star. If our primitive understanding of solar system formation is somewhat correct, Kepler should detect dozens of worlds orbiting in the liquid water ‘habitable zones’ of their primary stars. First results of HZ region planets will come from close in orbiting terrestrial planets of faint red M0 stars, possibly as early as Thanksgiving. Planets orbiting further out around bright stars like the G2 sun will take around 4 years from now to detect, as positive detection requires 3 repeat occultations to ensure against false positives. Kepler is an exciting mission for those curious if there are other well situated possibly habitable planets elsewhere. Fortunately, not everyone at NASA is an ideolog like James Hansen.
http://kepler.nasa.gov/
Since there are an enormous (if not infinite) number of stars in the Universe, and since many of them clearly have planets, the likelihood is that, even if our planet is atypical, there are still a very large number of such ‘atypical’ planets.
The real problem is how to get to them. One way is surely a Matter Transporter that transmits the information needed to reconstitute a living being at light speed, but unfortunately the distances are so great that light speed doesn’t get you very far in a short time.
So we really need a physics that supersedes Einstein, so we can invent the FTL (Faster Than Light) Hyperdrive or Intersplit (Jack Vance’s term) that will enable us to galavant about the Galaxy (and beyond) with abandon. Never say “never.”
But time’s a-wastin’. When I was a lad I assumed that by the 21st century I’d be on a ship headed for Alpha Centauri. Yet here we are, still phutzing about in Low-Earth Orbit, wondering if we can afford to return to the Moon—not to mention Mars. And fighting a rearguard action against neo-Luddites and eco-Marxists who want to take us backwards to “40 acres and a mule.”
What a disappointment!
/Mr Lynn
James P (02:16:06) :
…two of the most complex carbon-rich molecules ever found in interstellar space
So carbon’s not all bad, then!
Indeed, life is made of carbon. All living beings on Earth are made of carbon; no way for other elements. Three organic compounds essential for the emergence of life -everywhere in the known Universe- are methane, acetylene and hydrogen cyanide. These compounds are condenser agents which promotes the biopolymerization of proteins and carbohydrates. Of course, other compounds known like agglomerative substrates are needed; for example, fullerenes and silicon carbyde. Thus, life forms can exist on other extrasolar planets.
Regarding the class of star, it’s a determinant factor for the emergence and support of living beings. We could say that life stars are class F and class G. Nevertheless, the possibility of living beings which can survive on planets orbiting other classes of stars exists if they grow on twilight zones.
Interesting how artists have taken to conceptualizing other planets and stars as seen from outer space. “Photographic” detail in art is appealing, but one element of these images that always makes me wonder is the “filter interference”, here taking the form of hexagonal ghost images spaced along the sun’s “shaft” of light. Since all humans will ever see of extra-terrestrial planets or stars will be through layers of glass or plastic, I suppose the optics will always include such distortions. Still, it’s a layer of “reality” which always makes me do a double-take.
Maybe some optics or physics buff could explain why the images are hexagonal.
The Gliesian system will be around a long time — M-type red dwarfs have main-sequence lifetimes in the trillions of yrs.
Searching for life around a red dwarf star is probably an exercise in futility. High variability and flares knock the chances way, way down.
Bill P (09:10:46) :
. . . “Photographic” detail in art is appealing, but one element of these images that always makes me wonder is the “filter interference”, here taking the form of hexagonal ghost images spaced along the sun’s “shaft” of light. . . .
Maybe some optics or physics buff could explain why the images are hexagonal.
That’s a reflection (or rather a shadow) of the iris leaves off the internal surfaces of the camera lens. The iris is the adjustable part inside the lens that controls the amount of light going through the lens. Some lenses have more than six leaves and thus produce a differently shaped reflection.
“”” Ric Werme (16:27:40) :
George E. Smith (15:38:18) :
But if it is not uniform density throughout, then all bets are off and it would be different; my guess assuming a denser core is that it would then be bigger than cube root of 2 times, so gravity would be less.
Some non-uniformity is quite permissible. One of the few things I remember about such stuff is that a thin spherical shell of material of some density has a gravitational field outside of the shell exactly the same as an equivalent point mass at the center. (Inside the shell the field is zero.) So that means if the planet is nicely sorted, e.g. iron in the center, then silicates, then water, your first result is right. “””
Well Ric, you just tripped yourself up with your own shoe laces.
It is indeed true that any properly spherical shell (of any radial density function) appears externally to be a point mass at the centre, and inside the shell the gravity (due to the shell) is zero. Also if there were a uniform electric charge on the surface there is no electric field inside (Biot-Savart Law). If you go down inside the earth; the gravity depends only on the material inside your radius (assuming the earth is spherical which it isn’t)
But meanwhile back at your shell. Yes it has an equivalent mass acting as if it were at the center, but the surface gravity depends on the radius of the surface, so if the shell were so thin as to have no mass, but there was an iron core inside with a lot of mass, the relationship between the mass and the gravity would be different from that of a uniform sphere.
Assuming that the density is highest at the center (not a truly safe assumption), then any non uniform (bur radially symmetric) mass distribution, would have a bigger total radiaus for a given total mass, than a uniform sphere, so it would have lower surface gravity than a uniform sphere of the same mass.
Sorry, no mule, methane, y’know.
Mike, I’m sure you’re right. I think I’ve seen that effect myself when I used to take pictures with my Nikon. Haven’t shot a photo with that camera for awhile.
I was reading a Mir Shaviv blog entry recently, about his trip to Lapland, where he sees the concentric rings of his own filter while he’s trying to photograph the Aurora. His commentary on this is interesting.
Auroras in Lapland
Posted March 26th, 2009 by shavivcosmic rays Science weather & climate
http://www.sciencebits.com/auroras
Bill P (14:14:26) :
. . . I was reading a Mir Shaviv blog entry recently, about his trip to Lapland, where he sees the concentric rings of his own filter while he’s trying to photograph the Aurora. His commentary on this is interesting.
Auroras in Lapland
http://www.sciencebits.com/auroras
Those are great aurora photos, and just the pure green, too. The concentric circles are from internal reflections inside the UV filter, and the circular shape is due to a slight concavity or convexity in the filter. Machinists use precision ground glass disks called optical flats to check surface imperfections. Placing them on a surface with a monochrome light will produce interference bands that you can count to measure unflatness to wavelength precision.
Those really are neat photos.
Lens artifacts are also a big contributor to UFO reports.
And the so-called “Rods phenomenon” is due to the way modern video cameras process frames. Though the die-hard believers still think they’re inter-dimensional entities.
I’d bet that with that gravity, no one there would have osteoporosis.
😮