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Smallest Planet Outside Our Solar System Found

Zonk posted more than 6 years ago | from the hard-to-spot-with-all-the-space-dust dept.

Space 91

mikkl666 writes "Following the recent story about the discovery of the youngest planet outside our solar system, Spanish researchers now report that they found the smallest exoplanet observed so far. The planet, known as GJ 436c, was found by analyzing distortions in the orbit of another, larger planet, and its radius is only about 50 percent greater than the Earth's. The scientists are confident that their new method will lead to a series of further discoveries: 'I think we are very close, just a few years away, from detecting a planet like Earth.' You can also reference the the original paper online for further details."

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I claim this land for Spain! (1)

Mordok-DestroyerOfWo (1000167) | more than 6 years ago | (#23029440)

Here we go again with the Spanish. Although I can't wait to see the new line of Conquistadors in their jaunty uniforms.

Re:I claim this land for Spain! (0, Troll)

Jeremiah Cornelius (137) | more than 6 years ago | (#23029828)

Smallest object?

Bush's brain, or Cheney's heart?

Both are not of terrestrial, human origin.

Re:I claim this land for Spain! (1)

HasselhoffThePaladin (1191269) | more than 6 years ago | (#23030418)

That one's quite a stretch.
To save you all time, I am new here.

Re:I claim this land for Spain! (0, Offtopic)

AutoTheme (851553) | more than 6 years ago | (#23031406)

Gimme a fucking break! Uid of 137 makes this not a serious troll? Thought the mod system was so we didn't have to read troll/off-topic/bullshit!?!?

Make up your mind (0, Redundant)

calebt3 (1098475) | more than 6 years ago | (#23029458)

So is it the youngest, the smallest, or both?

Re:Make up your mind (2, Insightful)

calebt3 (1098475) | more than 6 years ago | (#23029466)

Nevermind... need to read summaries better.

SLASHDOT SUX0RZ (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#23029516)

_0_
\''\
'=o='
.|!|
.| |
estimate the radius of this [goatse.ch]

Analyzing distortions? (5, Funny)

monkeyboythom (796957) | more than 6 years ago | (#23029524)

So you are saying that I can deduce a small child hovering around an obese parent by the way the bigger person's fat jiggles? Brilliant! Now if it only works on fat chicks, then I can discover if they have a hot, smaller female friend nearby...

Re:Analyzing distortions? (0)

Anonymous Coward | more than 6 years ago | (#23029592)

I like how this man thinks, somebody hire him for a huge corporate think tank, we need these theories ASAP

Re:Analyzing distortions? (1)

ari_j (90255) | more than 6 years ago | (#23029606)

So you're saying that the bigger planets are going to start shooting at us and trying to get us to go home with them when we send manned missions to the Earthlike planet?

Re:Analyzing distortions? (1)

Oktober Sunset (838224) | more than 6 years ago | (#23030116)

So you're saying that the bigger planets are going to start shooting at us and trying to get us to go home with them when we send manned missions to the Earthlike planet?
Bloody hell! I've had a few desperate fat girls try n chat me up before, but never had one pull out a gun n start firing at me to get me in bed. What sort of bars do you hang out in??



If your curious, yes I did fuck those desperate fat girls, and the ugly ones too, hey, gotta get it while you can, n ugly girls need meaningless 1 night stands too!

Re:Analyzing distortions? (1)

ari_j (90255) | more than 6 years ago | (#23031214)

Ugly chicks here in the US can be pretty aggressive.

Re:Analyzing distortions? (5, Funny)

$RANDOMLUSER (804576) | more than 6 years ago | (#23029676)

Nah. With chicks, it's just the opposite. The small hot ones are always orbited by larger ones.

Re:Analyzing distortions? (1)

VShael (62735) | more than 6 years ago | (#23033712)

The small hot ones are usually dense.

(I'll avoid the "sucking anything in the area" jokes)

Re:Analyzing distortions? (0)

Anonymous Coward | more than 6 years ago | (#23029854)

My GOD but you've just reminded me of a horrible, horrible scene I witnessed on the dance floor of a nightclub many years ago.

Re:Analyzing distortions? (1)

Tablizer (95088) | more than 6 years ago | (#23031434)

works on fat chicks, then I can discover if they have a hot, smaller female friend nearby...

Forget it. Slashdotters ain't cool enuf for the slimmer one. Miss Drupiter for us, dude.
       

Re:Analyzing distortions? (2, Funny)

Pikoro (844299) | more than 6 years ago | (#23033864)

"Follow your dreams. You can reach your goals. I'm living proof. Beefcake! BEEFCAAAAAKE!"

Obligatory Duck Dodgers (1)

Abreu (173023) | more than 6 years ago | (#23029534)

I claim this planet on behalf of Mars!

Re:Obligatory Duck Dodgers (0)

Anonymous Coward | more than 6 years ago | (#23031190)

"God is dead" - Nietzsche, 1882

"Nietzsche is dead" - God, 1900
I know of no better life purpose than to perish in attempting the great and the impossible -Nietzsche, 1873

Re:Obligatory Duck Dodgers (0)

Anonymous Coward | more than 6 years ago | (#23034926)

I know of no better life purpose than to perish while dropping my pants by decree from the new Commander in Chief - Bill Clinton, 2009

Re:Obligatory Duck Dodgers (1)

armareum (925270) | more than 6 years ago | (#23046746)

Nice sig. I first saw it scratched into the door of a public toilet. At university, natch.

Hal Clement (4, Funny)

jdigriz (676802) | more than 6 years ago | (#23029536)

I think we have a Mission of Gravity here. 5x the mass of earth but only 50% more radius? I for one, welcome our Mesklinite Overlords.

Re:Hal Clement (2, Insightful)

Toonol (1057698) | more than 6 years ago | (#23030652)

Remember, if you hold density constant, an increase in radius translates to a power of three increase in volume, because it's expanding through three dimensions. A 50% increase in radius would result in a (1.5 ^ 3) 3.375 increase in mass. So, a five-fold increase in mass isn't that unreasonable; it's only a 48% increase in density. That's a lot, but you don't have to resort to white-dwarf style matter densities.

At 5x mass and 1.5x radius, I believe the surface gravity would only be about 2.2 g's.

factor of 2... (0)

Anonymous Coward | more than 6 years ago | (#23031804)

That's actually supposed to be a 6.75 times increase in volume.

Re:factor of 2... (0)

Anonymous Coward | more than 6 years ago | (#23033268)

That's actually supposed to be a 6.75 times increase in volume.
wrong.

A 50% increase in radius

4*(pi)*(r^3)/3=volume r=1.5*earth's so the ratio should be 1.5^3:1earth which is 3.375x as massive as earth at constant density.

Question for rocket scientists (1)

cjsm (804001) | more than 6 years ago | (#23032092)

At 5x mass and 1.5x radius, I believe the surface gravity would only be about 2.2 g's

This poses a question. Would rocket power be sufficient to get off a planet of this mass? On earth, it seems rockets are pushed to the limit to launch any significant payload. At twice earth gravity, it seems like your payloads would really be limited, if you can even reach escape velocity with rocket technology.

Re:Question for rocket scientists (3, Insightful)

iNaya (1049686) | more than 6 years ago | (#23032838)

I'm sure we'd have no problem with that sort of technology by the time we actually reached that planet.

Re:Question for rocket scientists (3, Insightful)

cjsm (804001) | more than 6 years ago | (#23034646)

Well, besides humans, this would also aply to any intelligent life that might evolve on such a planet. Would rocket technology be sufficient to get off a planet with two or three times the gravity of earth? At point would the gravity be too great for rocket technology to work?

I'm sure we'd have no problem with that sort of technology by the time we actually reached that planet.

Well, that's sort of a meaningless answer, since your talking about technology that doesn't exist either in reality or in theory. Why not talk about flying unicorns to solve the problem? Its just as unreal. No offense to you, but I'm mystified your answer was modded insightful. I've got news for the mods. WARP DRIVE DOESN'T EXIST, AND MAY NEVER EXIST. Just because its on Star Trek doesn't make it real. Warp drive violates the known laws of physics, and is likely impossible.

Re:Question for rocket scientists (1)

general scruff (938598) | more than 6 years ago | (#23036002)

Stop being such a killjoy!

planet definition (1)

line-bundle (235965) | more than 6 years ago | (#23029546)

what is the minmum possible size/mass of a planet according to the new definition of 'planet'?

Re:planet definition (2, Informative)

4D6963 (933028) | more than 6 years ago | (#23029764)

what is the minmum possible size/mass of a planet according to the new definition of 'planet'?

I don't know about that (well I do know but you could just look it up) but if a planet 4.7 times as heavy and 50% bigger than Earth was considered too small/lightweight to be considered a planet I'd seriously consider packing my bags and moving to a real planet like Uranus (to live in an airship of some sort that is, I'm very aware that you can't actually stand on Uranus, thank you!).

Re:planet definition (0)

Anonymous Coward | more than 6 years ago | (#23032468)

I'm very aware that you can't actually stand on Uranus, thank you!).


For a start, he'd need to be lying down.

Re:planet definition (1)

ross.w (87751) | more than 6 years ago | (#23032972)

You can sit on it though.

In your mother's basement.

Posting on Slashdot.

In reality... (2, Informative)

Tatarize (682683) | more than 6 years ago | (#23036304)

According to the IAU definition a planet needs to orbit around the Sun. No exoplanet is really a planet. Though the question depends a lot on what it's made of. It needs to be at hydrostatic equilibrium and fairly round (this is easier fluids and gases) and it needs to have cleared it's area.

Lets say it needs to be about the size of mercury and sweep the question under the rug as frankly a ball of water the size of a basketball, if the only object orbiting a star, would qualify as a planet.

Re:In reality... (1)

CTachyon (412849) | more than 6 years ago | (#23039812)

But a ball of water the size of a basketball would rapidly boil off into space, so it's not in hydrostatic equilibrium, is it?

Re:planet definition (1)

superslacker87 (998043) | more than 6 years ago | (#23030416)

I dunno. I'm still trying to

Re:planet definition (1)

superslacker87 (998043) | more than 6 years ago | (#23030442)

Well, now it won't be funny anymore... stupid new comment system I have to get used to.

I dunno. I'm still trying to figure out the air speed velocity of an unladen swallow.

Re:planet definition (2, Informative)

Ragzouken (943900) | more than 6 years ago | (#23030574)

It's more to do with the planet clearing its own orbit of debris rather than size, I think.

Re:planet definition (1)

jd (1658) | more than 6 years ago | (#23030614)

That depends on how generous the discoverer is with their money.

Re:planet definition (1)

wizardforce (1005805) | more than 6 years ago | (#23033274)

anything large enough to clear its immediate orbit and roughly sperical- quite arbitrary as Earth anda few other "planets" havent quite cleared their orbits either.

I call it... (4, Funny)

spazdor (902907) | more than 6 years ago | (#23029578)

'Pluto.'

Bearing in mind... (4, Insightful)

localroger (258128) | more than 6 years ago | (#23029610)

...from this distance and with this technique, Venus would qualify as "a planet like Earth." It would truly suck to be the person who hiked 50 light-years to find that out.

Re:Bearing in mind... (1)

carnivorouscow (1255116) | more than 6 years ago | (#23029708)

If we can identifying earth sized planets they can be cataloged until resolution improves enough for spectroscopy to be used to identify atmospheric composition.

Re:Bearing in mind... (1)

Kasis (918962) | more than 6 years ago | (#23030138)

And in the meantime it would seriously narrow down the SETI.

Re:Bearing in mind... (1)

rabiddeity (941737) | more than 6 years ago | (#23031596)

Don't assume that intelligent life could only develop on a planet exactly like ours. Even just considering carbon-based life as we know it, life could still survive just fine [molvray.com] in a higher or lower gravity version of Earth. Lower gravity would likely mean a thinner atmosphere but oceans would still be habitable. Higher gravity would mean life forms couldn't grow as large on land. I don't think either of those would prohibit intelligent life from developing. And that's also assuming intelligent life just stays at home on one planet, which is highly unlikely. Any species competitive enough to climb its way to intelligence will probably keep flourishing and expanding.

In short, we shouldn't just focus all our SETI efforts on a few star systems just because they're similar to Sol.

Re:Bearing in mind... (1)

carnivorouscow (1255116) | more than 6 years ago | (#23032512)

There is the possibility that life has developed on a planet very different from our own. However, we know for certain that inteligent life can develop on a planet like ours. When dealing with finite resources you frequently get better results staying with the known.

I'm not arguing that SETI should avoid any solar system that wasn't identical to ours, but it is far more probably that inteligent life would develop on a planet similar to ours.A planet wouldn't have to be a mirror image of earth but there's a reasonable upper and lower limit in terms of temperature, gravity and chemical composition.

The article is wrong (5, Informative)

Geoffrey.landis (926948) | more than 6 years ago | (#23029680)

The article seems to be wrong. Smaller planets have been discovered orbiting pulsars [wikipedia.org] . Check out PSF 1257+12a [extrasolar.net] for a small planet.

What they mean to say is that this seems to be the lowest mass planet found orbiting a main-sequence star.

It's also annoying that the press release quotes the radius of the planet (which cannot be measured, and is only an approximation based on guesses at density), when what they actually measured is the mass. Planetary densities vary widely; they have no idea what the radius is.

Re:The article is wrong (4, Insightful)

Kjella (173770) | more than 6 years ago | (#23029810)

This, ladies and gentlemen is why people don't RTFA. There's much better and accurate information in the comments. Can this mean that if the mass is higher but the density much lower, there could be earth-class gravity there? Would sound like a pretty good start to me...

Re:The article is wrong (3, Informative)

Falkkin (97268) | more than 6 years ago | (#23029890)

Yes, I wish we could score the article -1, Wrong. This is the smallest exoplanet discovered "around a Sun-like star". More details on this and previous discoveries can be found at the Bad Astronomy blog:

http://www.badastronomy.com/bablog/2008/04/10/no-its-not-the-smallest-exoplanet-found/ [badastronomy.com]

Re:The article is wrong (4, Informative)

CheshireCatCO (185193) | more than 6 years ago | (#23029900)

You got it. Phil Plait (aka, The Bad Astronomer) [badastronomy.com] ranted about this today.

Re:The article is wrong (1)

Geoffrey.landis (926948) | more than 6 years ago | (#23031680)

You got it. Phil Plait (aka, The Bad Astronomer) [badastronomy.com] ranted about this today.

Ah, good for Phil! I need to start checking him first.

Re:The article is wrong (3, Informative)

j1m+5n0w (749199) | more than 6 years ago | (#23029916)

From the article:

With a mass about five times greater than Earth's, it is the smallest planet yet discovered outside the solar system

From wikipedia article on Gliese 581c [wikipedia.org] :

Using the known minimum mass of the previously detected Gliese 581 b, and assuming the existence of Gliese 581 d, Gliese 581 c has a mass at least 5.03 times that of Earth. The mass of the planet cannot be very much larger than this or the system would be dynamically unstable.

It seems like it may be a little premature to assume that the new planet is the smallest, even when comparing to planets around main-sequence stars.

I agree the radius is probably a made up number.

Scientist: "Assuming a density similar to earth's, the radius of the planet would be 50% greater than Earth's."

Science reporter: "The planet's radius is 50% greater than Earth's."

Re:The article is wrong (1)

boris111 (837756) | more than 6 years ago | (#23029968)

I thought they could approximate the radius pretty well based on the dimming the planet does to the star as it passes across it. This provided the orbital planes lines up right for our viewing. Or does this only apply to large planets?

Re:The article is wrong (1)

SquirrelsUnite (1179759) | more than 6 years ago | (#23031878)

You can, if it passes between you and the star. This one apparently doesn't.

Re:The article is wrong (1)

SquirrelsUnite (1179759) | more than 6 years ago | (#23032356)

Scratch that, it might or it might not. But it was found differently and they didn't see a transit yet.

Re:The article is wrong (0)

Anonymous Coward | more than 6 years ago | (#23039976)

The answer lies in the second sentence of your question.

The light-dimming technique only works if we are looking at the solar-system almost exactly edge-on, so that the planet passes directly between us and the star.

However, the method that they used to discover this planet seems to work best when we are looking at the solar system top-down-- where the planets, from our point of view, circle around the star rather than passing in front of it.

(also, I don't know what the size-limit is for the dimming technique to work, so your last sentence may hold part of the answer as well.)

Re:The article is wrong (1)

jimmux (1096839) | more than 6 years ago | (#23030420)

If they are only guessing at density, then is it only conjecture that this is a rocky planet? Or is there some other way to determine this?

Re:The article is wrong (1)

SquirrelsUnite (1179759) | more than 6 years ago | (#23032342)

Even worse than wrong the Reuters article neglects to tell the interesting story of how this planet was found. Or less optimistically why the authors think it's there.

Astronomers have used various methods to find extra-solar planets but the two most successful ones are the radial velocity method and the transit method.
The RV method can be described at looking at how the star wobbles as a planet moves around it. Transits are simply partial eclipses. As the planet moves in front of the star it blocks out some of its light.

In 2004 a Neptune mass planet was found around this star with the radial velocity method. It was on an elliptic, 2.6 day orbit. This was surprising because they estimated that the orbit should become circular in a mere hundred million years due to tidal dissipation and the star is at least 6 billion years old. There had to be a second planet perturbing the Neptune-size planet, allowing it to retain its non-circular orbit. In the meantime they also looked for transits but they were out of luck, GJ 436b (the Neptune size planet) wasn't transiting. It wasn't just that they didn't see a transit they actually ruled it out. But in 2007 another team looked at the same star and now saw GJ 436b transiting. Apparently the plane of the planet's orbit shifted significantly in 3 years. This is impossible without having another planet in the system. From this they calculated the mass and orbit of the perturbing planet.
Finally they went back to the radial velocity data and tried to see if there was any indication of this perturbing planet. And there it was. It could be just noise but it matched up with their earlier calculation pretty well. So the change in the Neptune sized planets orbital inclination and the radial velocity data both point in the same direction which makes them pretty confident that there is a planet there with these characteristics.

Whats the use (1)

iNivas (1270892) | more than 6 years ago | (#23029682)

Before we discover such planets so far away, we should figure out a way to travel faster close to the speeds of light - i wouldn't wanna spend 30 precious years on a one leg journey

Re:Whats the use (1)

Omnifarious (11933) | more than 6 years ago | (#23029736)

There are two big problems with traveling that fast. The first is shielding. At really high speeds every stray atom becomes a cosmic ray. The second is the amount of energy and reaction mass needed.

Re:Whats the use (1)

G00F (241765) | more than 6 years ago | (#23031964)

Actually here are two problems as I see it

I agree with your shielding, force field would become a must for several reasons like radiation.
1. long range and real time sensory is a bigger issue. You are seeing things where they use to be, and moving that fast

Energy is the easy part, we continue to develop nuclear or work on antimatter. The size/mass of it wont matter once it is out of our gravity.

I think we wont get shielding or long range sensory till after we can create gravity(or anti gravity) with a flip of the switch.

Re:Whats the use (1)

Omnifarious (11933) | more than 6 years ago | (#23037172)

Do the math. About the only feasible designs for near C craft are ones that rely on being to scoop up interstellar hydrogen and use that. Even antimatter doesn't give you enough energy to be able to manage it.

Re:Whats the use (2, Insightful)

hansraj (458504) | more than 6 years ago | (#23029756)

Do you honestly believe that all technology either should develop "all at once" or should follow your chronology? Besides the point of looking deep into the space is not entirely to find a place for humanity to go. Just understanding the universe is a goal worth pursuing. At least that's how some other people view science and fortunately I should say.

Re:Whats the use (1)

iNivas (1270892) | more than 6 years ago | (#23029830)

Understanding is always good. But shouldn't we prioritize the research. The universe is so vast there is always a finite possibility of discovering earth like planets within finite time. When such a possibility already exists, it is worth investing in ways to actually make use of any such discovery.

Re:Whats the use (0)

Anonymous Coward | more than 6 years ago | (#23029918)

We already found one, looking into making it habitable in the medium to long term is probably a good thing.

Re:Whats the use (1)

geekoid (135745) | more than 6 years ago | (#23029944)

This way we will know where to go when we do figure out to travel to them in a reasonable way. perferable warp speed, or dimension skipping.

Re:Whats the use (0)

Anonymous Coward | more than 6 years ago | (#23030964)

But shouldn't we prioritize the research.
Who is we? Do we all have the same priorities and goals?

Granularity (1)

Nefarious Wheel (628136) | more than 6 years ago | (#23031374)

If you look over the last twenty years in relation to human history (to say nothing of geological time frames) technology has developed all at once. There's a huge, nay exponential effect on technology of having near universal communications and access to knowledge content. If you scrape off the foam from the top of the Internet, there's an aweful lot of beer there. It's nearly instantaneous from that perspective.

Then send me (1)

symbolset (646467) | more than 6 years ago | (#23032992)

Or send my son. He's four. I'll consent for him.

With food riots in Haiti [alertnet.org] you'll not lack for volunteers.

It's a small lifeboat after all. There's not room enough in it for everybody.

Hey, I'm smart, educated, resourceful and healthy. If you won't go send me!

just goes to show how crazy science is (3, Insightful)

jollyreaper (513215) | more than 6 years ago | (#23029746)

I remember watching my Star Trek and seeing them fly their starships right up to star systems because that was the only way to explore them. Shit, I suppose you'd still have to put sats in orbit and probes on the surface to do detailed science but holy shit, detecting planets from lightyears away, even making guesses as to habitability by looking at star type, planetary orbit, even getting spectrographic readings from the atmosphere. I never would have believe it in a book. Yeah, hyperdrives I could buy but not this. Reality is stranger than fiction. Heh, it's just like all of the scifi guys assuming that ambulatory robots would be the easy part and making them think fast and speak well would be the tough part.

Re:just goes to show how crazy science is (2, Funny)

boristdog (133725) | more than 6 years ago | (#23029788)

In Star Trek's defense, they DID have to get up close to find out if there were any hot alien chicks for Kirk to make out with.

Re:just goes to show how crazy science is (1)

CowboyNealOption (1262194) | more than 6 years ago | (#23029864)

This must be why holodecks were created; in spite of them being dangerous, it was the best way to keep captains like Captain Kirk from going on away missions.

Re:just goes to show how crazy science is (0)

Anonymous Coward | more than 6 years ago | (#23029922)

In Star Trek's defense, they DID have to get up close to find out if there were any hot alien chicks for Kirk to make out with.
The only chick I want to make out with is my sister.

Re:just goes to show how crazy science is (0)

Anonymous Coward | more than 6 years ago | (#23031896)

I wanna make out with your sister too

Re:just goes to show how crazy science is (3, Insightful)

geekoid (135745) | more than 6 years ago | (#23029806)

If we could bounce around from star to star within a week, that's how we would do it to.

We had already found it over 78 years ago. (1)

gapagos (1264716) | more than 6 years ago | (#23030126)

It name is Pluto.

Re:We had already found it over 78 years ago. (1)

petermgreen (876956) | more than 6 years ago | (#23031318)

pluto is part of the solar system, it may be a long way out but the sun is still the dominant factor in it's orbit.

It's not a planet. (1)

zippthorne (748122) | more than 6 years ago | (#23031688)

It doesn't even meet the first qualification for being a planet.

OK, dumb question... (2, Interesting)

Tastecicles (1153671) | more than 6 years ago | (#23031690)

...I'm ok with the orbital period of five days, that can be determined by the wobble the planet imparts to the star as it orbits. My problem is, how do they tell its rotational period?

Think about this for just a moment. Bright star, probably a hundred timed the diameter of the planet, and many thousands of times more luminous; assuming the planet is rocky (and barren, and a colouration about that of bleached tarmac), it'll have a reflectivity of about 15-20% (also known as albedo). Earth's blue-green marble surface and average 40% cloud cover gives it an albedo of around 35%. Given that the Voyager panorama barely picked up Earth from a distance of four billion miles, lost in the glare of our own sun, what chance do we in fact have of directly observing a body this close to its parent star, however dim it's a star and it's radiating stupid levels of energy, to be able to tell its rotation? And all from a distance of one hundred fifty trillion miles? You are not even going to see the planet in the glare, never mind seeing enough surface detail to determine how fast the bloody thing is spinning!

I think that they pulled the 22-day rotation out of their arses. Unless someone can tell me different?

Re:OK, dumb question... (1)

Plamadude30k (1271120) | more than 6 years ago | (#23031824)

Here's your answer: They can't actually see the planet itself, nobody's been able to directly image a planet in another solar system yet (this is something I hope to be working on in the next few years). What they can see in the case of Gliese 436 is that the light coming from the star "dips" in intensity a little on a regular basis. This is caused by the 'transit' of Gliese 436b, a neptune mass planet. Basically the planet blocks some light from the star and that is what we actually detect. Also with this system, we've done radial velocity measurements, which involves taking very accurate spectra of the star and watching how the spectral lines move (redshifted or blueshifted). This star, once the fit for the massive, known planet is taken out , still shows a consistent ~1 m/s/year radial velocity signal, which corresponds to a planet with roughly the characteristics described in above article

It's not really confirmed... (5, Informative)

Plamadude30k (1271120) | more than 6 years ago | (#23031782)

I (and a group of people) am actually researching this system myself. We observed a transit of GJ436b on March 30, and we're reducing the data now. I'd like to point out, however, this paper is NOT a discovery article. I read it in February (before it was published), and I've got it on my desk right in front of me. Basically, it PREDICTS that there MIGHT be a planet of said radius and mass in an orbit about twice as far out as GJ436b (a transiting hot neptune), but it also says that more study is needed to confirm the existence of this planet. What my study was trying to do was to show that there's a change in GJ436b's orbit caused by this new theoretical planet. So far, things look promising, but we haven't confirmed anything yet.

size isn't everything (1)

simplerThanPossible (1056682) | more than 6 years ago | (#23033280)

as far as size goes, Venus is Earth-like

There is no evidence it is a planet! (1)

bradbury (33372) | more than 6 years ago | (#23034720)

In case you haven't checked the reports, the scientists have not *seen* the object. Nor have they *seen* any of the other objects they so quickly claim are exoplanets.

If all you know are its mass, or diameter, and perhaps its orbital period that is insufficient information to claim it is a "planet". It should be a very large artificial satellite.

The astronomers are operating off of an assumption that the universe is dead (and therefore natural). Ooopps, then we probably shouldn't be here... They need to go read the papers by Charlie Lineweaver's group which document how *most* of the advanced technological civilizations in our galaxy may be much, much older than our own.

Re:There is no evidence it is a planet! (1)

balbord (447248) | more than 6 years ago | (#23035520)

Are you implying it may not be a moon?

err..

Ah crap. I always mess my Star Wars quotes.

Re:There is no evidence it is a planet! (1)

bradbury (33372) | more than 6 years ago | (#23036176)

No, not a moon. I am merely saying that when you only know its mass (or diameter) and or perhaps its orbital period, its a leap to go claiming something is a "planet".

Just FYI, the papers by Lineweaver's groups suggest that ~70% of the "Earths" in our galaxy are older than ours, some of them much much older. That leaves plenty of time for them to have developed the technology to disassemble and reassemble planetary sized masses (indeed if we develop robust nanotechnology in this century we will probably have such capabilities ourselves). A "reassembled" planet should not be called a planet -- it should be called a satellite.

Re:There is no evidence it is a planet! (1)

Plamadude30k (1271120) | more than 6 years ago | (#23048844)

You, of course, are making the assumption that there is intelligent extraterrestrial life outside our solar system, a claim which is supported by NO physical evidence. On the other hand, astronomers know that something large is there. Models of star formation predict that planets will form naturally when stars form. I'm going to go ahead and apply Ocham's razor here: 1)Large mass perturbing/blocking light from star 2)Good reason to think that it's a planet 3)No reason to think that an alien civilization even exists, much less has the capability, inclination, or materials to make GIANT space stations about the size of neptune. I'm going to go out on a limb and say that this one's a planet.

Re:There is no evidence it is a planet! (1)

bradbury (33372) | more than 6 years ago | (#23053896)

I don't disagree other than from the perspective that Lineweaver's argument says we are the "young kids on the block". You have physicists scratching their heads left and right trying to explain another observation "dark matter" when that is what you would have lots of if advanced civilizations simply converted their stars to Matrioshka Brains (complex Dyson Shells). But doing so would involve many civilizations far more advanced than we are and the physicists don't want to go there... (lets make up some magical new form of matter instead...).

Life is possible, we are here. We have good predictions for what our capabilities will be once we have robust molecular nanotechnology (and that includes taking the sun dark to external observers). And it is even possible at a slower rate without molecular nanotechnology (we are doing it now). Can they physicists make an argument that all of the planets they are finding are "dead"? That life on them can never develop? (I'll admit its tough on the planets we are currently finding but they are smoking guns for more hospitable planets.)

The scientists are failing to plug reasonable values into the "t" variable of the equation which would allow one to document the complete life history of such planets -- when you do that one may find that many of them have reached stages far beyond our current limited evolutionary state.

Re:There is no evidence it is a planet! (1)

Plamadude30k (1271120) | more than 6 years ago | (#23056298)

Alright, I won't argue, it seems you've convinced yourself of your own point rather handily and won't let go.

Re:There is no evidence it is a planet! (1)

bradbury (33372) | more than 6 years ago | (#23058094)

If it were only my reasoning, I might be more willing to take the easy way out and say all masses orbiting other stars are dead planets. But doing so screams of requiring a good explanation for why we are the first and/or only advanced technological civilization in our galaxy. Without some of those on the table the puzzle seems to be missing missing more than a few pieces.

Limits to detail (1)

WindShadow (977308) | more than 6 years ago | (#23037782)

What we can know about extra solar planets currently is rather limited by having to use multiple methods for each characteristic. Mass and orbit are estimated from orbital perturbation, size is estimated by occlusion, chemistry by several optical methods, none highly precise.

It seems likely that the quality of observation will not improve until better optical observation is possible, such as space based or multi site terrestrial installations. Currently we are making educated guesses.
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