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Comments: 341 + - Science: Exoplanet Has Showers of Pebbles on Thursday October 01 2009, @11:39AM
Posted
by
CmdrTaco
on Thursday October 01 2009, @11:39AM
from the gonna-need-a-thicker-umbrella dept.
from the gonna-need-a-thicker-umbrella dept.
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mmmscience writes "The newly-discovered exoplanet COROT-7b has an unusual form of precipitation: rocks. Because it orbits so close to its sun, the temperature on its sun-facing side is around 4220 degrees Fahrenheit. That's hot enough for rocks to vaporize — not unlike water evaporating on Earth. And, like Earth, when the vapor cools in the upper atmosphere, it forms clouds and begins to rain. But instead of water, COROT-7b gets a shower of pebbles."
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Wow (Score:5, Funny)
That's pretty cool, in a geeky sort of way.
I wish I could see it... but I don't think the environment would be terribly friendly to my sensitive skin.
Re:Wow (Score:5, Funny)
Yeah, I'm part Irish too. I can't stand being in the Sun/insert favorite star here.
Parent
Re:Wow (Score:5, Interesting)
The planet is tidally locked. Just stay on the dark side of the planet. The equilibrium temperature there is 59F [wustl.edu] -- not bad at all.
One thing that occurs to me is that if the mass transfer rate is as high as they're suggesting -- and I have no reason to suspect otherwise -- it seems to me that this planet would be *highly* tectonically active. Unlike rain, which just runs off, the pebbles will stick around where they fall. This means that the crust will have a lot of weight bearing down on it on the cold side, sinking into the mantle and likely leading to heavy volcanism and tectonic activity. And the erosion of the hot side should lead to an upwelling of exposed mantle material as the planet tries to relax into a sphere.
The awesome thing is, with such a reasonable temperature on the cool side, it could actually be habitable to LAWKI -- except for that likely lack of water thing, (unless there's been heavy cometary activity since the planet became tidally locked).
This planet must have an incredible range of minerals, way unlike anything on Earth -- the star basically mining the crust and even mantle on one side and depositing it after chemical vapor deposition onto the other side. If we ever go interstellar as a species, I wouldn't be surprised to see heavy mining activity on planets like that.
Parent
Oops (Score:5, Informative)
Parent
Re:Wow (Score:5, Interesting)
Oh, and sweet -- Some more highlights after further reading:
"Sodium, potassium, silicon monoxide and then oxygen -- either atomic or molecular oxygen -- make up most of the atmosphere." But there are also smaller amounts of the other elements found in silicate rock, such as magnesium, aluminum, calcium and iron. ... As you go higher the atmosphere gets cooler and eventually you get saturated with different types of 'rock' the way you get saturated with water in the atmosphere of Earth ... Elemental sodium and potassium, which have very low boiling points in comparison with rocks, do not rain out but would instead stay in the atmosphere, where they would form high gas clouds buffeted by the stellar wind from COROT-7.
So... the only one of those things that will be a gas at the surface on the far side is oxygen. The article says the atmosphere may not be breathable, but I have to wonder... why not?
Also, in the case what what condenses in the atmosphere is crystaline (I don't see anywhere which suggests whether they would be or not -- it all depends on how fast it cools), look at the list of the raining minerals:
enstatite, corundum, spinel, and wollastonite.
Enstatite can be a gemstone. Crystals of corundum are otherwise known as ruby and sapphire. There are many types of spinels, a number of whose crystals are considered gemstones. Etc. So *if* what condenses is crystalline, it could literally be raining gems on that planet.
Parent
Re:Wow (Score:5, Funny)
No, Ms. Morissette. Just coincidental.
Parent
Not unusual (Score:5, Funny)
We get solid precipitation here on earth all the time.
Sometimes it's hail, sometimes sleet.
The best is frogs, though.
Re:Not unusual (Score:5, Insightful)
We get solid precipitation here on earth all the time.
The parent raises a good point. How do we know the rock comes back down to the surface as a solid? Why doesn't it rain lava?
Parent
Re:Not unusual (Score:5, Informative)
The parent raises a good point. How do we know the rock comes back down to the surface as a solid? Why doesn't it rain lava?
I'm going to make an educated guess, and say it's in the same way we "know" that it rains any kind of rock at all -- because that's what the simulations said. It says they even varied constraints based on not knowing exactly what the composition of the planet is, but they kept ending up with the same basic result.
So it all comes down to how good the simulation model is. It's possible it's inaccurate in a way that it is right that there is rock-based precipitation, but that it's in liquid form, but I certainly have no idea.
Parent
Re:Not unusual (Score:5, Interesting)
Parent
Summary inaccurate (Score:3, Insightful)
Re:Summary inaccurate (Score:5, Interesting)
True. Also, I'm wondering if "pebbles" is an appropriate description of the condensed rock or if it wouldn't be more aptly described as "sand" or even "dust". Raindrops stick together; depending on how quickly the rock condenses, it might not have time to grow very large. (Then again, it could grow like hail, if the rock was in the liquid state for any significant amount of time.)
Parent
Re: (Score:3, Funny)
Yeah. "Pebbles" is probably inaccurate. I find it hard to believe the hypothesis that there are storms on this planet where redheaded female pre-historic babies with pony tails fall out of the sky.
Re:Summary inaccurate (Score:5, Insightful)
To be fair, the original press release also mangles observed and simulated results like crazy. They've definitely found the exoplanet and determined its orbit and mass. They've either confirmed or hypothesised from simulation that there are no volatile compounds on or around the planet, which they hypothesise is due to bake-out. They've hypothesised based on simulations that it is likely to have a rock-based atmosphere which, depending on composition, could be verified spectroscopically.
Parent
Flintstones (Score:3, Insightful)
This is just like on the Flintstones, where everything is made out of stone -- because it's the Stone Age, silly! Further research will reveal the pterodactyl airplanes, I'm sure.
Related to the current poll ? (Score:5, Informative)
Re:Related to the current poll ? (Score:5, Funny)
Parent
Re:Related to the current poll ? (Score:5, Funny)
I now know I won't need to pack a jacket while visiting this planet.
Please yourself. But I'll be taking my tungsten jacket (melting point 3422 Celcius, 6192 Fahrenheit).
You know, the one my grandmother bought me..... with the hood and the double pleated asbestos lining? I don't care if you've never liked it and it doesn't match my shoes, I'm wearing it.
Parent
Re:Related to the current poll ? (Score:5, Funny)
Or 2599 kelvin
Or the heat from burning 2 library's on congress.
Anyone know what it is in elephants ?
Parent
Re:Related to the current poll ? (Score:5, Funny)
Or the heat from burning 2 library's on congress.
Do libraries burn differently on congress than anywhere else?
Parent
Re:Related to the current poll ? (Score:5, Funny)
Yep, there's so much hot air there they burn way better.
Parent
Re:Related to the current poll ? (Score:4, Informative)
Parent
Re:Related to the current poll ? (Score:5, Funny)
Thanks,and stop calling me Kelvin
Parent
Re:Related to the current poll ? (Score:4, Funny)
Shirley you can't be Sirius?
Parent
Re:Related to the current poll ? (Score:5, Funny)
So 4220 degrees Fahrenheit is approximately 2600 degree Kelvin. Fixed it for you.
is approximately 2600 degree Kelvin
degree Kelvin
Fail. Hand in your geek card.
Parent
Re:FYI, about Kelvin (Score:4, Informative)
Parent
Rock Rainbows? (Score:5, Interesting)
Given that different material will have different melting temperatures, that should lead to the different metals coalescing at different heights. At sunset, there ought to be a layering affect as the last rocks fall back to the surface, a rock rainbow in effect. Of course, it probably won't last long with the whole planet being molten.
Re:Rock Rainbows? (Score:5, Insightful)
So no sunset.
Parent
Re:Rock Rainbows? (Score:5, Insightful)
I would also observe that "molten rock" is not famous for its transparency, let alone "gaseous rock". It may be an "atmosphere", but there won't be anybody observing any sort of "rainbow". The word "atmosphere" may be deceptive in this context; think less "open sky" and more "sea of blindingly hot lava so hot it's gaseous, not that you have any reason to care about this distinction".
Parent
Why were you late for school? (Score:5, Funny)
Teacher: Why are you late?
Student 1: I was throwing pebbles in the pond.
Teacher: (to student #2) Why are you late?
Student 2: I was throwing pebbles in the pond.
Teacher: (to student #3) Let me guess - you were throwing pebbles in the pond too?
Student 3: I'm Pebbles.
50% chance of rocking out! (Score:5, Funny)
It is nearly impossible to imagine a deluge of pebbles falling from the sky, or turning on the morning forecast to hear reports of "rocking" instead of "raining."
Oh I can imagine it. You see dark clouds roll in, crowding around. In the distance but growing louder, the rapid heavy percussion of the rock shower begins. Then in the cloud at the front, you see a flash of light and a shower of sparks like a pyrotechnic burst. Seconds later, instead of a crash of thunder, you hear the wail of an electric guitar.
It is now rocking. Rocking hard core.
This is the awesomest planet ever.
Obligatory S*P reference (Score:5, Funny)
Fallout (Score:5, Interesting)
That has happened on Earth too. We call it Fallout.
I am not kidding. A surface nuclear burst in the megaton range will vaporize millions of tons of rock and soil. This material will cool, condense, and and fall as
little pebbles or hail. In this case, it's radioactive, but otherwise the physics is the same.
Re:Fallout (Score:5, Interesting)
To enjoy a natural one, without the radioactive waste, all you need is a volcano eruption.
Parent
Let's not exaggerate (Score:5, Informative)
Some hyperbole here.
The Castle Bravo test shot (http://en.wikipedia.org/wiki/Castle_Bravo) was one of the largest thermonuclear detonations ever, with an estimated yield of 15-22 MT. The blast crater from Bravo was 2000m in diameter and 75m deep. Assuming it was square because I'm too lazy for math today, that's about 300,000 cubic meters. Assuming that this was blasted in solid granite (http://www.allmeasures.com/Formulae/static/materials/32/density.htm) you get about 780k metric tons.
However, most of this material wasn't vaporized, it was pulverized by the shock wave and propelled as a solid into the mushroom cloud. The actual quantity of material melted I wouldn't hazard to estimate, but it was a small proportion of the overall material excavated.
Much as in the "it's raining rocks!" planet, this precipitation would be much closer in form to dust, not "pebbles". One of the reason that water on earth comes in larger forms is that the water molecule has a charge, and will aggregate electrostatically. I don't think that would be true of this silicate cloud.
Parent
Re:Let's not exaggerate (Score:4, Insightful)
Actually a 75m section of a 2000m cylinder, from pi * r^2 * depth comes out at about 200 MILLION cubic metres. Multiply that by about two metric tonnes per cubic metre (sandstone) and you get four hundred million metric tonnes. I can't be bothered to account for the curvature of the crater, but I doubt it'll bring that down much under a hundred million tonnes. There's still the "vapourisation versus excavation" question, of course, I'm just pointing out that your estimate of mass is off by three orders of magnitude.
Parent
Re:Let's not exaggerate (Score:4, Informative)
Parent
Meanwhile on COROT-7b (Score:5, Interesting)
Meanwhile on COROT-7b scientists find a new planet so cold that water would actually create "oceans" on the surface , and even freeze at the poles.
They laugh at the though ever existing on that planet.
Re:Meanwhile on COROT-7b (Score:5, Funny)
t of life
Here, you dropped this.
Parent
Reality Stranger than Fiction (Score:3, Insightful)
If you consider the variety of habitats that we find life in our tiny part of the cosmos (Earth) and that life keeps being discovered in more and bizarre places (by human standards) when you extrapolate that out, I tend to think it may be literally beyond our imagination.
If we, by whatever means, met intelligent life, would we be able to communicate; sure math is universal, but consider the issues communicating ideas and values across cultures when its the same species. Consider a collective consciousness, what does the term "I" or "me" mean to it (them).
Really? (Score:3, Insightful)
It is nearly impossible to imagine a deluge of pebbles falling from the sky, or turning on the morning forecast to hear reports of âoerockingâ instead of âoeraining.â
Does this seem difficult to imagine, let alone nearly impossible?
Imagine, if you can, something somewhere else very similar to something standard here!
I'm Singing in the OW! OW! (Score:5, Funny)
ow!
geologist's hot dating destination? (Score:4, Funny)
Conveyor-belt planet (Score:5, Interesting)
Re:Conveyor-belt planet (Score:4, Informative)
Parent
Re: (Score:3, Funny)
No, they wouldn't be able to stand the constant rock music drumming on the roof.
Re:The sky is falling? (Score:5, Funny)
The sky is falling?
More like the ground is falling...from the sky.
Parent
Re:The sky is falling? (Score:5, Funny)
So it's like Australia?
Parent
Re:first (Score:5, Funny)
bite it noobs
forgot to check the AC box? noob!
Parent
Re:Titinians say the same thing about Earth (Score:5, Funny)
Parent