I just had an interesting thought...

CometPhoenix · Apr 3, 2008

We have discovered an exoplanet so close to its star, that the star stopped the planet's rotation. What would happen to the night side of that planet? Would it be incredibly hot, because it's so cold to the star, or would it be cold because it's constantly night? If it was hot at night, would it be a suitable environment for life? <div class="Discussion_UserSignature"> What ever happens, happens/Just call me Phoenix </div>

duck_theory · Apr 3, 2008

It depends. Like whether or not the planet has an atmosphere. If it does, the night side will still have heat distributed to it. On the other hand, if it is that close to the star, any atmosphere would likely be blasted off by the sun. Unless the planet has a strong magnetic field. So many things to consider. How large is this planet you talk about? If it is very big (and all planets discovered have either been gas giants or very large rocky planets. I think the smallest was just discovered - 5 times the size of Earth.) then the gravity will most likely make it hard for life to form. Unless it's ocean life.  <div class="Discussion_UserSignature"> It is by will alone I set my mind in motion. </div>

CometPhoenix · Apr 3, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>It depends. Like whether or not the planet has an atmosphere. If it does, the night side will still have heat distributed to it. On the other hand, if it is that close to the star, any atmosphere would likely be blasted off by the sun. Unless the planet has a strong magnetic field. So many things to consider. How large is this planet you talk about? If it is very big (and all planets discovered have either been gas giants or very large rocky planets. I think the smallest was just discovered - 5 times the size of Earth.) then the gravity will most likely make it hard for life to form. Unless it's ocean life.  Posted by duck_theory</DIV> I believe it was an Jupiter sized gas giant, which doesn't make any sense because the gases should have been blown off. Unless I guess if the planet is massive enough to hold the gases. <div class="Discussion_UserSignature"> What ever happens, happens/Just call me Phoenix </div>

duck_theory · Apr 3, 2008

Well there you have your answer. Nothing can live in or on a gas giant like Jupiter (at least nothing we can imagine). If the planet was rocky, there might have been a possibility. <div class="Discussion_UserSignature"> It is by will alone I set my mind in motion. </div>

qso1 · Apr 3, 2008

I believe it was an Jupiter sized gas giant, which doesn't make any sense because the gases should have been blown off. Unless I guess if the planet is massive enough to hold the gases. Posted by CometPhoenixThats a good point, keeping in mind the vast majority of exoplanets discovered so far are well over Jupiter mass and in torch orbits. Something must be keeping those atmospheres from blowing off. And chances are, the atmorpheres do blow off, but over lengthy periods of time, perhaps decades.  <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

duck_theory · Apr 3, 2008

Decades? Isn't that a little fast in stellar event terms? <div class="Discussion_UserSignature"> It is by will alone I set my mind in motion. </div>

Saiph · Apr 3, 2008

You could look at mercury for an example of a rocky planet.  Granted, it's not entirely tidally locked, but it's pretty close (a 2/3 resonances.  Every 2 orbits it rotates 3 times...or vice versa, I don't recall). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

qso1 · Apr 3, 2008

Decades? Isn't that a little fast in stellar event terms? Posted by duck_theoryProbably but I think it possible in some cases and it is only a guess on my part.  <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

derekmcd · Apr 3, 2008

Even Mercury at a distance of .4 au has an atmosphere, albiet a very thin one.  Hot Jupiter's are generally the same distance and sometimes closer, but the density of their atmospheres are many orders of magnitude higher than what what we have here on earth.  They maintain their atmosphere due to their enormous gravity.  They probablly don't have a magnetosphere to protect them as they are tidally loccked. It's likely that their upper atmosphere might experience some ionization causing some loss, but it is not an effect you would notice over mere decades.  Maybe over several hundred million years you might be able to see a measureable difference. The stellar winds may be intense at this distance, but it really relative.  I don't know what the particle density is, but it's not really analogous to wind blowing through your hair.  Other than heat convection on mars (Edit:  I meant mercury, of which there would be no heat convection with such a thin atmospher), the solar winds don't make it 'windy'.  My point is, though the stellar winds on a hot jupiter might be considered intense, it is still a really, really slow process.At least, that's my understanding... i could be wrong.  <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

baulten · Apr 4, 2008

Uh, it hasn't stopped rotating.  It's rotation period is the same as its revolution period.  Tidal locking is what that's called.Also, most exosolar planets we know of are tidally locked gas-giants in ultra-tight orbits aroung their parent stars.  Unsuitable for life.Of course, you could be refering to the Gliese 581 system which has a hot neptune and 2 super-Earths, all of which should be tidally locked.  A thick atmosphere could distribute the warmth on these worlds and there would be a terminator zone that experiences day and night cycles (possibly) like Earth or other "fast" rotating planets.  It would be impossible, due to the conservation of momentum, for a planet to NOT rotate.  The closest thing to this are planets with 90 degree tilts on their axises like Uranus, but they still rotate, just more like an "end over end" rotation due to the axial tilt.

qso1 · Apr 4, 2008

Even Mercury at a distance of .4 au has an atmosphere, albiet a very thin one.  Hot Jupiter's are generally the same distance and sometimes closer, but the density of their atmospheres are many orders of magnitude higher than what what we have here on earth.  They maintain their atmosphere due to their enormous gravity.We could be seeing the last century or millinia of Mercurys atmosphere blowing off. And I mentioned decades because I was just trying to make an educated guess because I don't think anyone really knows how long it would take. It could also vary from planet to planet just as you mentioned the difference in atmospheric density of hot Jupiters.The wind blowing thing was something I thought about because the sun causes comets to leave a trail as they swing in close to the sun. I reasoned that the same may happen to a planet in a torch orbit, only the tail so to speak, would last much longer and most likely much longer than the mere decades I mentioned earlier.  <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

MeteorWayne · Apr 4, 2008

The whole point of the MESSENGER mission is to attempt to learn the answers to these questions. From the MESSENGER website:http://messenger.jhuapl.edu/index.php<div align="left" style="padding-right:0.6em;padding-left:0.6em;padding-bottom:0.4em;font:bold0.75emArial;margin-left:0px;width:380px;color:#ffffff;padding-top:0.4em;background-color:#000000;border:#be55403pxsolid">Question 1: Why is Mercury so dense?</div>Mercury's density implies that a metal-rich core occupies at least 60% of the planet's mass, a figure twice as great as for Earth! MESSENGER will acquire compositional and mineralogical information to distinguish among the current theories for why Mercury is so dense. <div align="left" style="padding-right:0.6em;padding-left:0.6em;padding-bottom:0.4em;font:bold0.75emArial;margin-left:0px;width:380px;color:#ffffff;padding-top:0.4em;background-color:#000000;border:#be55403pxsolid">Question 2: What is the geologic history of Mercury?</div>Only 45% of the surface of Mercury has been imaged by a spacecraft! Using its full suite of instruments, MESSENGER will investigate the geologic history of Mercury in great detail, including the portions of the planet never seen by Mariner 10. <div align="left" style="padding-right:0.6em;padding-left:0.6em;padding-bottom:0.4em;font:bold0.75emArial;margin-left:0px;width:380px;color:#ffffff;padding-top:0.4em;background-color:#000000;border:#be55403pxsolid">Question 3: What is the nature of Mercury's magnetic field?</div>Mercury has a global internal magnetic field, as does Earth, but Mars and Venus do not. By characterizing Mercury's magnetic field, MESSENGER will help answer the question of why the inner planets differ in their magnetic histories.  <div align="left" style="padding-right:0.6em;padding-left:0.6em;padding-bottom:0.4em;font:bold0.75emArial;margin-left:0px;width:380px;color:#ffffff;padding-top:0.4em;background-color:#000000;border:#be55403pxsolid">Question 4: What is the structure of Mercury's core?</div>Through a combination of measurements of Mercury's gravity field and observations by the laser altimeter, MESSENGER will determine the size of Mercury's core and verify that Mercury's outer core is molten. <div align="left" style="padding-right:0.6em;padding-left:0.6em;padding-bottom:0.4em;font:bold0.75emArial;margin-left:0px;width:380px;color:#ffffff;padding-top:0.4em;background-color:#000000;border:#be55403pxsolid">Question 5: What are the unusual materials at Mercury's poles?</div>At Mercury's poles, some crater interiors have permanently shadowed areas that contain highly reflective material at radar wavelengths. Could this material be ice, even though Mercury is the closest planet to the Sun? MESSENGER will find out. <div align="left" style="padding-right:0.6em;padding-left:0.6em;padding-bottom:0.4em;font:bold0.75emArial;margin-left:0px;width:380px;color:#ffffff;padding-top:0.4em;background-color:#000000;border:#be55403pxsolid">Question 6: What volatiles are important at Mercury?</div>MESSENGER will measure the composition of Mercury's thin exosphere, providing insights into the processes that are responsible for its existence. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Apr 4, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>You could look at mercury for an example of a rocky planet.  Granted, it's not entirely tidally locked, but it's pretty close (a 2/3 resonances.  Every 2 orbits it rotates 3 times...or vice versa, I don't recall). Posted by Saiph</DIV>Hi Saiph, Mercury rotates 3 times for every two orbits around the Sun. Mercury rotates once every 59 days, orbital period around the Sun, 88 days. Every 88 days, Mercury rotates one & a half times, so when Mercury reaches the same point in its orbit, the opposite side is facing the Sun.Therefore Mercury has two 'hot poles' i.e when the Sun is directly overhead at Perihelion. One is on the equator south of the Caloris Basin, the other at the antipode, on the equator north of the Weird Terrain (antipodal to Caloris).  Cheers MeteorWayne for reminding people about the importance of the MESSENGER mission. A great post.Jupiter's Escape Velocity is 59.5 KPS / 214,000 KPS or 36.9 MPS / 133,000 MPH.IIRC, Jupiter would not lose its atmosphere in a torch orbit, despite the high temperatures & strength of the Solar Wind, Jupiter's gravity is more that strong enough to survive such conditions. Yes the atmosphere will balloon outwards considerably, but will not escape.Upsilon Andromedae B temperatures below. http://www.solstation.com/stars2/ups4andb.jpg <img src="http://sitelife.space.com/ver1.0/Content/images/store/11/13/db375684-8140-4e1e-bd5b-ddb0266b9761.Medium.jpg" alt="" />Hot spot on Hot Jupiter HD 1989733 B.http://www.solstation.com/stars2/hd189th2.jpg <img src="http://sitelife.space.com/ver1.0/Content/images/store/6/14/b650ff18-2424-4e98-9e29-67e2a4e471cd.Medium.jpg" alt="" /> Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

back2reason · Apr 6, 2008

Here's a thought I have not seen before:  Though there's been lots of talk about terraforming Mars, I have not seen anything about how one might terraform Venus.  Is the thought that preposterous?What sort of chemical intervention into Venus' atmoshpere would coalesce moisture, and precipitate its bulk, perhaps allowing it to cool?  There should be no dispute over the advantages of terraforming Venus rather than Mars.  Needless to say this is way beyond my technical background.  Perhaps there are readers out there who are not quite as limited. John Ruseckas

MeteorWayne · Apr 7, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Here's a thought I have not seen before:  Though there's been lots of talk about terraforming Mars, I have not seen anything about how one might terraform Venus.  Is the thought that preposterous?What sort of chemical intervention into Venus' atmoshpere would coalesce moisture, and precipitate its bulk, perhaps allowing it to cool?  There should be no dispute over the advantages of terraforming Venus rather than Mars.  Needless to say this is way beyond my technical background.  Perhaps there are readers out there who are not quite as limited. John Ruseckas    Posted by back2reason</DIV>There is almost no water on Venus. The clouds are not water clouds, rather they are sulfuric acid. I read today that if all the water on Venus were condensed out (impossible at those temperatures, but... ) It would be a layer 1 cm thick. On earth, it's about 3 km thick. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

derekmcd · Apr 9, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>There is almost no water on Venus. The clouds are not water clouds, rather they are sulfuric acid. I read today that if all the water on Venus were condensed out (impossible at those temperatures, but... ) It would be a layer 1 cm thick. On earth, it's about 3 km thick. Posted by MeteorWayne</DIV> Not to mention, that Venus is simply too hot.  Everything we send there doesn't last very long.  <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

neilsox · Jun 5, 2008

This is adapted from terriform Venus ideas here and elsewhere, and the 11 kilometer peak a few hundred kilometers from the North pole of Venus. Please embellish, refute and/or comment. This is of interest to me as the location for partially terriforming a small (size of Australia) portion of Venus. A snow fence with a radius of about 2000 kilometers surrounds the pole and the 11 kilometer peak. Fence circumfrence about 12,566 kilometers catches dust, raising the elevation. Portions of the fence need to be moved or replaced anually. In about 10,000 years, the area inside the fence may reach an average elevation of 11 kilometers, with some parts perhaps 20 kilometers. The high elevation cools the plateau to perhaps 300 degrees c. A giant Sun shade a million or so kilometers from Venus in the sunward direction cools the plateau to about 150 degrees c. This allows it to rain sulpheric acid on the plateau. Just before the first rain falls, the plateau is covered with an impervious layer so the acid does not sink below the surface of the plateau which is likely still hot enough to boil sulpheric acid. Over about 10,000 more years nearly all of the sulpheric acid in the atmosphere of Venus will be trapped in artificial acquifers of the great polar plateau. Venus can then be bombared with ice comets, which will permit real water rain to fall on the polar plateau. With a new giant sun shade which is transparent only to photons best for photosynthesis, we can now grow crops on the highest elevations of the polar plateau. Genetically altered humans can tend these crops naked except for an oxygen face mask. Since the atmosphere is still about 90% carbon dioxide, a prothesis is needed to remove carbon dioxide from the blood. It may take a million years to get the carbon dioxide of all of Venus below 1%, even with extensive agriculture on the great polar plateau. There are numerous ways to hurry the terriforming process, but most require enormous resources. Terriforming all of Venus will take much longer and far more resources, without the help of tecnology that we cannot yet even imagine.   Neil.

eburacum45 · Jun 8, 2008

Well, some people can imagine that technology, neilsox:http://www.rfreitas.com/Astro/TerraformSRS1983.htmthere are certain difficulties associated with the self-replication concept, but as a self-replicating machine myself, I can say that they are not all insuperable.  These people are making the first steps along that route...http://reprap.org/bin/view/Main/WebHome <div class="Discussion_UserSignature"> ---------------------------------------------------------------http://orionsarm.com http://thestarlark.blogspot.com/ </div>

eburacum45 · Jun 8, 2008

Some interesting images of a simulation of a tidally locked planet's atmosphere here, http://arxiv.org/PS_cache/astro-ph/ps/0209/0209227v2.fig1.jpgfrom this paper http://www.citebase.org/fulltext?format=application%2Fpdf&identifier=oai%3AarXiv.org%3Aastro-ph%2F0209227  <div class="Discussion_UserSignature"> ---------------------------------------------------------------http://orionsarm.com http://thestarlark.blogspot.com/ </div>

eburacum45 · Jun 8, 2008

Here is a celestia model I've made of a tidally locked planet inspired by that simulationhttp://www.flickr.com/photos/25577499@N07/2560863448/ <div class="Discussion_UserSignature"> ---------------------------------------------------------------http://orionsarm.com http://thestarlark.blogspot.com/ </div>

thebigcat · Jun 8, 2008

Excellent <div class="Discussion_UserSignature"> </div>

tomorows_scientist · Jun 11, 2008

well i agree it would depend on if the planet still has an atmousphere. i remember learning about a planet that was really close to a star but it had a very slow rotation and it was expected that the dark side would be EXTREAMLY cold do to there would be almost no heat in it but then scientists discovered the winds on the planet carried the heat to the other side of the planet extreamly quickly in fact i think that planet at well the time that i learned this had the most extream winds that was known at like i said at that time. so if this planet had an atmousphere and had some extream winds wich i might expect do to the cooliness on the dark side combining with the heat of the side facing the star would combine and create some pretty extream winds to carry the heat  around the planet. <div class="Discussion_UserSignature"> </div>

crazyeddie · Jun 11, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Here's a thought I have not seen before:  Though there's been lots of talk about terraforming Mars, I have not seen anything about how one might terraform Venus.  Is the thought that preposterous?What sort of chemical intervention into Venus' atmoshpere would coalesce moisture, and precipitate its bulk, perhaps allowing it to cool?  There should be no dispute over the advantages of terraforming Venus rather than Mars.  Needless to say this is way beyond my technical background.  Perhaps there are readers out there who are not quite as limited. John Ruseckas    Posted by back2reason</DIV>Actually, Venus is a rather poor prospect for terraforming, in spite of it's similarity in size to Earth.  It rotates very slowly, in 243 days, and there is no practical way to speed it up.  It's atmosphere is so dense and hot that it crushes everything we put on it's surface.  It has a huge amount of CO2 that must some how be removed via energy-intensive means, and no water to speak of.  And how do you cool it off?  A massive sunscreen, sometimes called a soletta, would do the trick, but the cost of building such a huge structure would be enormous.Any way you look at it, Mars is a more suitable choice for terraforming.  <div class="Discussion_UserSignature"> </div>

I just had an interesting thought...

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