'Darkest' world enlightens astronomers about mysterious light-gobbling planet

Sep 27, 2011 by Morgan Kelly
Astronomers from Princeton University and the Harvard-Smithsonian Center for Astrophysics found that the distant exoplanet TrES-2b -- shownhere in an artist's conception -- likely absorbs 99.9 percent of the light that strikes it, making it the most light-thirsty object in the known universe. The findings may help astronomers better understand a mysterious characteristic of similar planets found outside our solar system. (Image by David A. Aguilar, Harvard-Smithsonian Center for Astrophysics)

(PhysOrg.com) -- A giant Jupiter-like gas planet has been revealed to be the most light-thirsty object in the known universe -- a finding that may help astronomers better understand a mysterious characteristic of similar planets found outside our solar system.

Recent analysis on a planet dubbed TrES-2b has found that it probably absorbs 99.9 percent of the light that strikes it, more than any other known cosmic entity, according to a report by Princeton University's David Spiegel, a postdoctoral researcher in the Department of Astrophysical Sciences, and lead author David Kipping, a postdoctoral researcher at the Harvard-Smithsonian Center for Astrophysics.

Recently published in the journal , the paper not only identifies the planet as the "darkest" world yet observed, but also sets a new standard in determining just how much light "hot Jupiter" -- scorching balls of hydrogen and helium already known for being non-reflective -- can keep to themselves.

TrES-2b, which was discovered in 2006, is one of roughly 150 hot Jupiter planets known to exist outside our . Astronomers are working to better understand the sometimes mysterious properties of these "dark" planets, from their mass to their orbital patterns to their atmospheric makeup.

In the case of TrES-2b and other , "darkness" refers not to the absence of light, but rather the amount of it absorbs, explained Spiegel. By that standard, TrES-2b is exceptionally "darker" than any substance found on Earth. Coal, among the darkest substances on Earth, absorbs 95 percent of the visible light that strikes it, reflecting only 5 percent of the visible light; TrES-2b absorbs all but 0.1 percent of the light that heads its way. However, TrES-2b orbits so close to its star that it is extremely hot and glows thermally -- despite its "darkness," if the planet was in Earth's solar system it would appear 3,000 times brighter than Venus, the solar system's brightest planet.

Spiegel, who focuses his research on the habitability and atmospheric and interior conditions of exoplanets -- those found outside our solar system -- noted that his and Kipping's work is among the first to find visible light emerging from an exoplanet in addition to the infrared light more typically observed.

Finding evidence of a puzzling component

What little light TrES-2b emits, relative to the amount it absorbs, is comparable to that from a burner on an electric stove, Spiegel said. The planet gives off a reddish glow of visible light while 95 percent of light coming from the planet is emitted as heat. This is an unusually high level of light obscuration, even among hot Jupiters, which are famously opaque. TrES-2b's dimness suggests that the planet is strongly influenced by a still-mysterious atmospheric component characteristic of hot Jupiter planets that absorbs an extraordinary amount of visible light, but had not been previously identified in TrES-2b, Spiegel said.

"We found evidence suggesting that something that seems to be present and absorb light in other planets hasn't been accounted for in basic models of TrES-2b," Spiegel said. "It looks like there's something missing from our list of 'ingredients' that make up the atmosphere of this planet. It is absorbing a lot of the optical light that hits this planet, but we're not sure what that extra ingredient is."

Kipping and Spiegel's finding adds another layer to the complex personality of hot Jupiter planets, said Gaspar Bakos, a Princeton assistant professor of astrophysical sciences noted for his work detecting exoplanets. First observed nearly 15 years ago, hot Jupiter planets can be readily detected with current observational instruments due to their size and orbital motion, and reveal new information about distant stars and solar systems.

"Hot Jupiters keep bringing us surprises," Bakos said. "First, some of them were found to be too big and too light compared to most theories. Then some turned out to be super-massive and compact. Some of them are 'well-mannered' and orbit their stars in the same direction as the star spins. Yet some are 'ill-mannered' with a retrograde orbit. Some the stars on close to circular orbits, but others were found to follow wildly eccentric (elongated) orbits. The fact that TrES-2b is so 'dark' is yet another surprise."

TrES-2b has been a popular observation target for astronomers, particularly after the 2009 launch of NASA's Kepler satellite telescope brought the planet into clearer view, Spiegel said. In 2010, he and Princeton astrophysical sciences professor Adam Burrows published an analysis in The Astrophysical Journal of atmospheric data of TrES-2b and two other planets in Kepler's view. Because of that work, Kipping approached Spiegel with his own observations of TrES-2b as it orbited its sun.

Via the Kepler satellite, Kipping had, over several months, captured the planet as it passed in front of the star it orbits, TrES-2; took on full illumination as it started to duck behind the star; and finally fell into TrES-2's shadow. This cycle presented the planet at its brightest and dimmest -- and Kipping noted that the difference between the two was unexpectedly slight, suggesting that TrES-2b was retaining much of the light that hit it. Spiegel checked Kipping's observations against dozens of atmospheric models to find those that best explained the planet's lack of reflectivity.

The most applicable models factored in high levels of the enigmatic, light-absorbing compound thought to be in the atmosphere of other "dark" hot Jupiters, Spiegel said. Should that mystery element be behind TrES-2b's massive light absorption, then Spiegel and Kipping's research also reveals that whatever the compound is, it has the ability to soak up much more visible light than had previously been calculated, Spiegel said.

"This is not the first reporting of the mystery element," Spiegel said. "But it is the first identification of how non-reflective it can make a planet."

In addition to their observations, Kipping and Spiegel's research emphasizes the benefit of publicly available data from satellites such as Kepler, said Princeton's Bakos.

"This paper presents a thorough analysis of high-quality, publicly available Kepler spacecraft data and combines it with cutting-edge theoretical interpretation," Bakos said, noting the availability of this data to the scientific community allows for creative work to be done in analyzing findings made outside our solar system.

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Quasi_Intellectual
5 / 5 (4) Sep 27, 2011
Reminds me of that dark planet from "the Fifth Element".
kevinrtrs
1.3 / 5 (25) Sep 27, 2011
"Hot Jupiters keep bringing us surprises," Bakos said. "First, some of them were found to be too big and too light compared to most theories. Then some turned out to be super-massive and compact. Some of them are 'well-mannered' and orbit their stars in the same direction as the star spins. Yet some are 'ill-mannered' with a retrograde orbit. Some orbit the stars on close to circular orbits, but others were found to follow wildly eccentric (elongated) orbits. The fact that TrES-2b is so 'dark' is yet another surprise."

So just how long are they going to slog away hoping to absolutely confirm the accretion theory when most observations simply falsify it? When will someone have the guts to stand up and denounce it for what it is: a lot of hot air?
Smellyhat
1 / 5 (1) Sep 27, 2011
I'm perplexed by the "artist's conception" image, and even more perplexed having realized that the person who created it was a physicist. That is not what I had imagined a planet which was absorbing 99.9 percent of the light that struck it would look like. I thought it would be...darker. Less reflectance. Fewer giant white clouds.
Palli
5 / 5 (2) Sep 27, 2011
kevin, are you referring to your own observations? Are you saying that accretion doesn't happen at all? how do galaxies form if not by accretion of dust and gasses?
hush1
1 / 5 (1) Sep 27, 2011
Imagine planets displaying unknown compositions of compounds.
Each planet a 'manual book' of all the sciences for the interactions between their stars and themselves.

As if their 'manual books' harbor potential to contribute to our understanding and even control over all the science that governs the interactions between our Sun and the planet Earth.

A foreign planet compound harmless to earth and offering controllable sunlight and thus, climate.

You can say I am a dreamer.
Star_Gazer
3.7 / 5 (3) Sep 27, 2011
Light-gobbling.. Light-thirsty.. Is this a quirkiest article title contest?
Jaeherys
5 / 5 (3) Sep 27, 2011
@Smellyhat
TrES-2b orbits so close to its star that it is extremely hot and glows thermally -- despite its "darkness," if the planet was in Earth's solar system it would appear 3,000 times brighter than Venus


Because in the picture the planet is so close to its sun, even though it's absorbing most of the light hitting it, it is still very bright, ie. emitting light because it is so hot.

But relative to the sun it looks pretty dark but not completely black.

If on the other hand, say a billion km from its sun, then maybe it'd appear as you expect it would, pitch black.
Nanobanano
1 / 5 (1) Sep 27, 2011
"This is not the first reporting of the mystery element," Spiegel said. "But it is the first identification of how non-reflective it can make a planet."


Very interesting, and after reading the article, I'm left with 3 hypothesis:

1) "New" Exotic isotope of a known element, somehow shifting the isotope's absorbtion spectra beyond anything we know.

2) Exotic unkown chemical compound made of known elements.

3) Unknown heavy element in a gaseous or plasma phase due to extreme temperature. This could be anything from element 113 to 118 or beyond, since we don't know how these elements behave in molar quantities in actual solids, liquids, or gaseous phases. They have only been observed in particle accelerators as individual atoms.

Noble gases are greenhouse gases, making an unknown, stable isotope of element 118 (or the next exotic one beyond that,) possible "new" elemental candidates for the mystery element.
Nanobanano
2 / 5 (3) Sep 27, 2011
Of course, the problem I see with an unknown element or an unknown isotope is that it should be detected in the surrounding environment of the star and planet, and possibly inside the star itself, not just on the planet. That is, UNLESS the planet formed elsewhere and was later captured by the star.

Of course, there's always the possibility that we just don't know enough about how large quantities of known elements behave in extreme gravitational environments such as a Jupiter mas planet. Maybe the absorbtion and emission spectra and thermal properties are altered under the right gravitational conditions...
El_Nose
4.6 / 5 (5) Sep 27, 2011
just because you find examples that go against the grain -- much like any general statement fails when applied to individual results/or figures - it does not disprove the general truth of the matter.

If i said stars are hot - and someone brought up every brown dwarf in creatioon as a counter argument they would still be wrong - because in general stars are hot
javjav
4.2 / 5 (6) Sep 27, 2011
"likely absorbs 99.9 percent of the light that strikes it, making it the most light-thirsty object in the known universe."

Aren't black holes more light-thirsty?

Eric_B
1 / 5 (1) Sep 27, 2011
i suppose they are not defining black holes as existing in the known universe. or, they have some hack/journalist writing these headlines again...
PosterusNeticus
4.1 / 5 (7) Sep 27, 2011
"likely absorbs 99.9 percent of the light that strikes it, making it the most light-thirsty object in the known universe."

Aren't black holes more light-thirsty?


Absorbing light and trapping light in inescapably bent and twisted space aren't the same thing. In the former case you have ordinary electromagnetic interaction of light & matter. In the latter case the light has effectively fallen down a well and can't climb back out.
Pirouette
1.3 / 5 (6) Sep 27, 2011
Could there be a possibility that this "planet" is a full-to-the -brim "black hole" that is almost filled to capacity and was captured by the star which it revolves around? The "missing ingredient" in its atmosphere, if it truly has an atmosphere as suggested in the article, just may be the remnants of that gravitational characteristic which a spent star from long ago that has already collapsed into itself and began to draw inward all matter, gases and light that is nearby.
This "planet" may have been a rogue black hole that was thrown out of its original orbit and had been traveling through the galaxy or through the space between galaxies, swallowing matter as it went, then finally settling into an orbit around a star. It still absorbs matter and light from its surroundings, but it is probably close to capacity but is still absorbing much light while emittance is negligible.
I would suggest that this is probably the case, in that a black hole exhibits pretty much the same attributes
Pirouette
1.3 / 5 (6) Sep 27, 2011
Wondering now if a slight "event horizon" has been detected by the researchers in the vicinity of this "planet", and how many other planets, if any, are further from it at a relatively safe distance.
I suppose there is no way to tell when a black hole has reached its limit of ingesting matter and energy, but I would think that eventually it should reach a point of saturation after billions of our years.. No?
stealthc
1 / 5 (4) Sep 27, 2011
perhaps the planet isn't as big as you think it is and it is a micro black hole? Seems like you've found one, finally.
PosterusNeticus
4.5 / 5 (10) Sep 27, 2011
perhaps the planet isn't as big as you think it is and it is a micro black hole? Seems like you've found one, finally.


No. Kepler detects planets using the transit method; measuring the "light dip" as the planet passes between the star and the spacecraft.

Kepler is sensitive but not sensitive enough to see a body ~22 feet in diameter* from 750 ly away. And even if it were, obviously the light curve of an orbiting body the size of Jupiter would look very different from that of an orbiting body just a few meters in size.

It's a planet, not a black hole.

(* I say roughly 22' in diameter because that's what I come up with as the Schwarzschild radius for a body of 1.19 Jupiter masses)
PosterusNeticus
1 / 5 (1) Sep 27, 2011
.
Nanobanano
3.1 / 5 (7) Sep 27, 2011
It's a planet, not a black hole.

(* I say roughly 22' in diameter because that's what I come up with as the Schwarzschild radius for a body of 1.19 Jupiter masses)


five stars.

See, my first hunch as I was reading the article was "intermediate black hole" (i.e. between stellar and micro,) but I kept reading the article, which shows clear evidence that it couldn't be a black hole in any case, as you pointed out.

This object clearly has emission spectra, just not so much in the visible range.

Regardless, we're left with some sort of exotic isotope theory, or some sort of exotic gravitational or thermal effect which we don't understand from the experience of objects and elements in our own solar system...

There is ONE other far-FAR-fetched possibility which I did not think of earlier, which is a Dyson Megastructure.

After all, a Dyson Megastructure should shift the emission spectra of it's host object towards the infrared.
Nanobanano
3.7 / 5 (9) Sep 27, 2011
Now, this is one of the characteristics you would look for when looking for a Kardashev Type 1 to Type 2 civilization:

1) A planet that absorbs an abnormally high amount of light.

2) A planet that emitts an abnormally high amount of IR radiation.

The planet MIGHT be covered by an orbitting swarm (or a single sphere) of highly efficient "solar" collectors.

While the probability of this is very, very low, it fits the basic profile.
Nanobanano
2.7 / 5 (6) Sep 27, 2011
I mean, what are the odds of a planet existing whch has a significant portion of it's atmosphere being composed of an unknown stable isotope of element 118 (or the next higher hypothetical Noble Gas element?)

That CAN'T have any better odds than the Drake equation. Can it?

And if it is made out of such an exotic element or exotic isotope, where did it come from, and why doesn't it exist any place else in detectable quantities, and how did it get so concentrated in one place to make an entire planet's atmosphere out of it?

Whatever it is, we're talking ridiculously long odds of this phenomenon happening...
Silverhill
5 / 5 (4) Sep 27, 2011
Pirouette:
I suppose there is no way to tell when a black hole has reached its limit of ingesting matter and energy, but I would think that eventually it should reach a point of saturation after billions of our years.. No?
Indeed, no. there is no upper bound on how much mass can be gathered into one spot. Consider the black holes that are thought to exist at the centers of (many) galaxies, equal to millions or billions of solar masses.

(quoting the article)
Should that mystery element be behind TrES-2b's massive light absorption, then Spiegel and Kipping's research also reveals that whatever the compound is...
Note the word 'compound'. 'Element', here, means "a component or constituent of a whole, or one of the parts into which a whole may be resolved by analysis." [credit: dictionary.com]

IOW, *something* (presumed to be a molecular compound) in the atmosphere absorbs a lot of light.
Pirouette
1 / 5 (4) Sep 27, 2011
Not all black holes reside in the center of galaxies. When a star goes supernova, it can be in any part of any galaxy, then depending on favorable conditions, it can become a black hole. But when you say that "there is no upper bound on how much mass can be gathered into one spot", I think that you also subscribe to the hypothesis that all matter in the Universe was concentrated into one very small point in time and space just before the "big bang" and, if that was the case, you would be correct as to the limitless consumptionability (my word) of planet-sized or tiny black holes cannibalizing matter.

OK, let's suppose you are correct and it isn't a black hole. What possible mysterious compound or group thereof could be absorbing so much photon energy to the point of preventing very little of it to escape outward? I had a weird idea that it may be a planet-wide battery. (chuckling to myself).
PosterusNeticus
4.5 / 5 (8) Sep 28, 2011
Not all black holes reside in the center of galaxies. When a star goes supernova, it can be in any part of any galaxy,


Stop. The point he was getting across is that there are black holes billions of times more massive than this body. The question of an upper bound is irrelevant, because even if there is one obviously it's a number with many more zeroes and commas than the mass of this body.

OK, let's suppose you are correct and it isn't a black hole.


It's not a black hole because 1) it's far, far too big for its mass and 2) it's not black, it's just really dark. It does emit some light.

What possible mysterious compound or group thereof could be absorbing so much photon energy to the point of preventing very little of it to escape outward?


Welcome to the article. This is what they're working on: why are some of these hot Jupiters so dark?
UnlimitedRealms
2.3 / 5 (3) Sep 28, 2011
If the compound can be discovered and then replicated here on earth , reaserched , refined , it would make a great photonic collector , absorb light then release it as heat energy . We have that tech now working here in Nevada and other places , but the light absorbstion rate is not nearly as close to what they have found the exoplanet . What we have now has to be in concetrated and/or focused light to work . This new compound could reduce the area need to focus light to the collector .
Robert_Wells
not rated yet Sep 28, 2011
If the compound can be discovered and then replicated here on earth , reaserched , refined , it would make a great photonic collector , absorb light then release it as heat energy . We have that tech now working here in Nevada and other places , but the light absorbstion rate is not nearly as close to what they have found the exoplanet . What we have now has to be in concetrated and/or focused light to work . This new compound could reduce the area need to focus light to the collector .


this planet is referred to as a Hot Jupiter, therefore its safe to assume that it orbits its star/s between approximately 0.015 and 0.5 AU. i would consider that
concetrated and/or focused light.
.

wouldn't you?
El_Nose
5 / 5 (1) Sep 29, 2011
just because it absorbs light energy well does not imply that it releases energy well.
Pirouette
1 / 5 (4) Sep 29, 2011
I'm not so sure that it is impossible for it to be a Jupiter-sized black hole. Thinking along the lines of a youngish black hole that was captured by its host star and is far enough away from said star, as well as other bodies of matter/energy sources. If that is the case, then this dark but not black "hot Jupiter" is left without "food" to consume while it remains in orbit with the exception of photons absorbed from its host star - 99.9% of which it absorbs and retains. Considering that it is a Jupiter-sized "planet", it may well have been an enormous star in its former "life" that exploded and lost most of its mass, then careened out of its natural orbit as a Jupiter- sized brown star, then finally settling down while consuming mass and/or energy (photons) from nearby matter. I think it may be prevented from becoming a full-fledged black hole by some process which is preventing it from collapsing in on itself completely.
Pirouette
1 / 5 (2) Sep 29, 2011
I reread the article, which specifically says that "In the case of TrES-2b and other cosmic objects, "darkness" refers not to the absence of light, but rather the amount of visible light it absorbs." Therefore, the artist's conception is not to be accepted as an accurate visualization of that "exoplanet".
The phrase, "likely absorbs 99.9 percent of the light that strikes it, making it the most light-thirsty object in the known universe" is irritating, as well as other phrases from scientists such as: may be, could be, might be, likely, probably, possibly, etc. (I, too, am guilty of such ambiguity). I am uncertain also, and am not aware of, any such compound(s) that can absorb that much light, so we are all, basically, as far as I know, at the same level of knowledge as our scientists. In effect, I am at a loss, also.
typicalguy
5 / 5 (1) Sep 29, 2011
I sure hope the Vorlons show up to destroy that shadow fleet before they spot us.

I bet the US military can't wait to coat spy satellites, bombers, missiles, you name it, out of a compound that will make it invisible.
Pirouette
1 / 5 (5) Sep 29, 2011
@typicalguy

:Yes, the "Hitchhikers' Guide to the Galaxy" series of novels by Douglas Adams are entertaining. My teenaged son appreciated getting them for Christmas one year. He is 22 now and prefers reading materiel about celestial mechanics and other good stuff, such as theoretical mathematics.
And what would YOU like to do when you grow up?
typicalguy
5 / 5 (6) Sep 29, 2011
Pirouette, actually it was a Babylon 5 reference. Clearly you never saw the show or read the hitchhiker guide. It probably would have taken less time to google vorlons than to type your post.

Oh and I find it quite ironic that someone attempting 'put downs' on the Internet would imply another person is immature.
PinkElephant
5 / 5 (1) Sep 30, 2011
I bet the US military can't wait to coat spy satellites, bombers, missiles, you name it, out of a compound that will make it invisible.
Why wait?

http://www.physor...809.html

The article above is dated from 3 years ago...

On the other hand, merely absorbing incoming light isn't really a guarantee of stealth. The real problem is to avoid shining like a tracer round against the dark background of space, in the infrared spectrum, due to internal as well as absorbed solar heat. Maybe something with a short transit time, like a missile, might be sheathed in a pre-chilled thermal blanket (coated with the super-dark paint, of course.) But long-lived objects like satellites in orbits other than those around the 1st or 3rd Lagrange points, would find it impossible to hide from Earth-based infrared telescopes.
hush1
not rated yet Sep 30, 2011
lol
If only we were not children*
*(of all ages),
then our loss is even greater.

When directly addressing the subject the comments reflect the best part (of the child) in you. Not all of the parts that make us are the best, obviously.

The observation simply motivated an explanation outside the known. Conventional explanations within known science also have potential - to be overlooked. Intentionally or unintentionally.
hush1
not rated yet Sep 30, 2011
Thks for the link, PE.
Pirouette
1 / 5 (3) Sep 30, 2011
I was under the impression that the Vorlons were the tiny fleet of warships sailing through outer space that were swallowed by a yawning dog before they could attack. I only took a glimpse of Hitchhiker, then promptly went back to reading Scientific American at the time.
I ASSUMED that you were one of those teenage punks who roam these hallowed sites since you were completely off-topic with your statement about Vorlons. I apologize for my mistake and making you feel bad.
GreyLensman
5 / 5 (1) Oct 01, 2011
I mean, what are the odds of a planet existing whch has a significant portion of it's atmosphere being composed of an unknown stable isotope of element 118 (or the next higher hypothetical Noble Gas element?)

No need for element 118. It is quite clear from the article that a compound is believed to be the cause, almost certainly a carbon compound. The confusion is caused by the writer's sloppy use of the word 'element'.
GreyLensman
not rated yet Oct 01, 2011
just because it absorbs light energy well does not imply that it releases energy well.


You might want to look up "black body radiation" and reconsider that statement!
GreyLensman
4 / 5 (3) Oct 01, 2011
Now, this is one of the characteristics you would look for when looking for a Kardashev Type 1 to Type 2 civilization:

Occam's Razor. More than a shaving implement.
Nanobanano
1 / 5 (3) Oct 01, 2011
Occam's Razor. More than a shaving implement.


A fallacious application of that principle.

They said it was an unknown element. If that was a mistake, then the author of the article should print a retraction.

The author's use of the term "mystery element" is confusing, because he also said elswhere that no "substance" on earth absorbed that much light. Taken together, this seems to imply an unknown element.

However, the context is confusing, because he seems to be inadvertantly using "element" and "compound" enterchangeably, even though that is most certainly inappropriate.

I thought of common "soot" for compounds, but if it's true that this absorbs more light than any known "substance" on earth, it would seem they would have thought of that already.
brentrobot
5 / 5 (1) Oct 01, 2011
I would like seti to point their array at it for a couple days.
Nanobanano
2.3 / 5 (3) Oct 01, 2011
I would like seti to point their array at it for a couple days.


Yeah, but the thing is, Seti's instruments are completely useless for finding deep space communications anyway.

It could be a super-massive carbon planet.

Or it could be a Type 1 Civilization with advanced meta-materials in their solar panels.

Or it could be a planet made out of element 118.
Nanobanano
3 / 5 (2) Oct 02, 2011
Oh well, laugh it up.

Looking for a Dyson Megastructure, or at least evidence of a planet covered in solar collectors, is one of the most likely methods to succeed in finding advanced aliens, that is, if they exist.

You aren't likely to find a transmission from an alien, and even if you do, you probably won't recognize it as such, nevermind understand it.

Conventional radio transmissions degrade after a few light years.

So you'd have to intercept some sort of focused beam of light or some other carrier, and the odds of detecting a "Stray" message in such a format is ridiculously low: Astronomical, in fact.

http://www.youtub...LmgJGuvw
Nanobanano
3 / 5 (2) Oct 02, 2011
Truth is, I don't think the "Habitable Zone" for planets is as large as people normally claim, at least not for anything other than extremophiles.

Earth's mean temperature is 287k, maximum is 331k, minimum 184k.

If Earth was 5% farther from the Sun, the solar constant would be reduced by 9.3% (per unit area,) and the mean temperature would be reduced by about 28 kelvin, not counting additional negative feedbacks from glaciation and sea ice increasing albedo. In short, the Earth would QUICKLY become a complete snowball, even in the equator, if it was just 5% farther from the Sun.

On the other hand, if the Earth was 5% closer to the Sun then there would be a 9.75% increase in Solar Constant per unit area, and this would increase Mean temperature by 28 Kelvin, up to 107.6f MEAN, not counting additonal positive feedbacks from the existing ice melting totally, permanently, and positive feedbacks from thermolysis of organic matter making tons of CO2.
Nanobanano
2.5 / 5 (2) Oct 02, 2011
...cont...

In the hot scenario above, because all the ice would melt, the Earth's average albedo would be reduced to about 0.20, instead of the existing 0.30, which means that net solar input would be driven up by yet another factor of about 10% of the Solar Constant. So changing the Earth's position by 5% closer to the Sun would ultimately drive up it's mean temperature by about 20% or more in Kelvins, by the time you count all feedbacks...

While moving the Earth away from the Sun by 5%, due to glaciation and other negative feedbacks, would reduce the Earth's temperature dramatically more than the 10% of the inverse square law alone.

To me, this suggest that the Habitable Zone for Earth is probably LESS than plus or minus 10% of 1a.u. (adjusted for the Star's luminosity).

If the Earth was just 5% closer to the Sun, the maximum daytime high would probably be above boiling, i.e. 212f/100c, in some deserts.

57.8c plus 28.7c = 86.5c

Ignores 10% positive albedo feedback..
Nanobanano
3 / 5 (2) Oct 02, 2011
I think it's physically impossible to have more than 1 or 2 planets in any star's habitable zone. If you removed Earth and had two planets orbitting the Sun, at 0.90a.u. and 1.1a.u., it's unlikely either of them would be habitable Earth's humans or land animals, except maybe in a cave. It might be habitable to some sort of single celled organisms or multi-cellualr aquatic life...other than that, it would be like living in 25c to 50C hotter than death valley, or 25c to 50c colder than antarctica, with just a 5% distance change...

...UNLESS it's a very large, very bright and massive star and the planets orbit at a great distance where a couple percent change in distance could be relatively small in real linear distance.

However, large stars allegedly have very short lifetimes, so it wouldn't be a safe place to live and build a civilization...

So I think the habitable zone is even smaller than people claim, certainly for multicellular life, as we have any conception anyway.
Nanobanano
1 / 5 (1) Oct 02, 2011
And then you have to figure that if the planets were as close together as 0.9a.u. and 1.1a.u., then one of them would have probably gotten ejected from the system, at least around our own star anyway.

Of course, you could theoretically have a "binary planet", where both the "planet" and the "moon" are large enough and the right composition to be habitable. Imagine a "Super Earth" which as an "Earth" for a moon. Both objects could be habitable with the right atmospheric conditions...
yyz
5 / 5 (2) Oct 02, 2011
"Looking for a Dyson Megastructure, or at least evidence of a planet covered in solar collectors, is one of the most likely methods to succeed in finding advanced aliens, that is, if they exist."

Nano, searches for Dyson spheres (and partially built sructures) have been undertaken, most notably by Richard Carrigan at Fermilab: http://home.fnal....arch.htm

[...and references within]

In 2008, Dr. Carrigan published a paper in the Astrophysical Journal detailing the rationale behind the work and discussing results to date: http://iopscience...2075.pdf
Pirouette
1 / 5 (3) Oct 02, 2011
And then you have to figure that if the planets were as close together as 0.9a.u. and 1.1a.u., then one of them would have probably gotten ejected from the system, at least around our own star anyway.

Of course, you could theoretically have a "binary planet", where both the "planet" and the "moon" are large enough and the right composition to be habitable. Imagine a "Super Earth" which as an "Earth" for a moon. Both objects could be habitable with the right atmospheric conditions...


Nano. . would it not be feasible if 2 Earths were equidistant from each other within the same orbit going around the Sun and within the habitable zone, but on opposite sides of the Sun where it would be almost impossible for either Earth to make visual contact with the other? Much less know about the other's existence if both were populated?
Pirouette
1.5 / 5 (4) Oct 02, 2011
Regarding Solar collectors built by extraterrestrials on the "planet" in question, I doubt that a "hot Jupiter" sized planet that revolves that close to its star would have the need for such collectors since enough heat would be afforded from said star to run thermal energy turbines, if they are so equipped, to produce electricity. Also, Cosmic Filaments running between star and planet might be another source of power if the planet has a magnetosphere. But, I am still in favor of the young black hole possibility because 99.9% rate of absorption is a tremendous amount to suck inwards and retain. But what do I know. :)
Robert_Wells
not rated yet Oct 03, 2011
Nano. . would it not be feasible if 2 Earths were equidistant from each other within the same orbit going around the Sun and within the habitable zone, but on opposite sides of the Sun where it would be almost impossible for either Earth to make visual contact with the other? Much less know about the other's existence if both were populated?


no, brush up on your planet formation theory. should answer your own question about 15 minutes after you start researching, but if you cannot figure it out on your own i'd be happy to educate.

also a side note, check what the new guidelines are to be classified as a planet, something along the lines of 'has to clear its orbit'... therefore, technically those 2 bodies in the same orbit wouldn't be planets *shrugs* i'm just nitpicking now i know...sorry couldn't help it.
hint: that does loosely relate to planet formation you should be starting to research now
Pirouette
1 / 5 (2) Oct 05, 2011
I knew that planet formation starts from a disk surrounding a star. But the disk surrounds the star completely, not just one side of it. Therefore, it should be possible for one of more planets to form on the other side of the star which cannot be seen because you cannot see through the star to the other side of it. And one of those planets on the opposite side of the star could be in the same orbit as one on the side that is readily seen. Such a scenario could have happened in our own Earth orbit with another planet like ours that had formed on the opposite side of the Sun that shares our zone and orbital distance from the Sun.
Similar to sitting on a merry-go-round horse on one side of the m-g-r and a friend sitting directly opposite you on another horse on the other side of the m-g-r. You both are going around in the same "orbit" but will never catch up to one another.
pokerdice1
not rated yet Oct 08, 2011
The planet on the other side would not have the exact mass, size or densities... AND slight velocity varients in the incipient masses (that you propose) would not move at the same rate. The odds of two worlds agglomerating with the initial (forming at the same time, as well!) orbital characteristics consonant with avoiding the other planet in the same orbital at some later time, is incalculaby small. They would also have to be the only large bodies in the system as even two bodies with the same structural and initial orbital charactersitics would be assymetrically perturbed by other bodies in the system.

PS: This obviously means that an orbit clearing event must occur.