Vaporizing the Earth

From Washington University in St. Louis, and in honor of melted globe week, here’s one more thing for weepy Bill McKibben to worry about.

Caption: Scientists at Washington University have simulated the atmospheres of hot Earth-like planets, such as CoRoT-7b, shown here in an artist’s conception. CoRoT-7b orbits so close to its star that its starward side is an ocean of molten rock. By looking for atmospheres like those generated by the simulations, astronomers should be able to identify Earth-like exoplanets. Credit: A.. Leger/Icarus

In science fiction novels, evil overlords and hostile aliens often threaten to vaporize the Earth. At the beginning of The Hitchhikers Guide to the Galaxy, the officiously bureaucratic aliens called Vogons, authors of the third-worst poetry in the universe, actually follow through on the threat, destroying the Earth to make way for a hyperspatial express route.

“We scientists are not content just to talk about vaporizing the Earth,” says Bruce Fegley, professor of earth and planetary sciences at Washington University in St. Louis, tongue firmly in cheek. “We want to understand exactly what it would be like if it happened.”

And in fact Fegley, PhD, and his colleagues Katharina Lodders, PhD, a research professor of earth and planetary sciences who is currently on assignment at the National Science Foundation, and Laura Schaefer, currently a graduate student at Harvard University, have vaporized the Earth — if only by simulation, that is mathematically and inside a computer.

They weren’t just practicing their evil overlord skills. By baking model Earths, they are trying to figure out what astronomers should see when they look at the atmospheres of super-Earths in a bid to learn the planets’ compositions.

Super-earths are planets outside our solar system (exoplanets) that are more massive than Earth but less massive than Neptune and made of rock instead of gas. Because of the techniques used to find them, most of the detected super-Earths are those which orbit close to their stars —within rock-melting distance.

Their NSF- and NASA-funded research, described in the August 10 issue of The Astrophysical Journal, show that Earth-like planets as hot as these exoplanets would have atmospheres composed mostly of steam and carbon dioxide, with smaller amounts of other gases that could be used to distinguish one planetary composition from another.

The WUSTL team is collaborating with Dr. Mark Marley’s research group at the NASA Ames Research Center to convert the gas abundances they have calculated into synthetic spectra the planet hunters can compare to spectra they measure.

Motivated by degeneracy

Under favorable circumstances planet hunting techniques allow astronomers not just to find exoplanets but also to measure their average density.

The average density together with theoretical models lets the astronomers figure out the bulk chemical composition of gas giants, but in the case of rocky planets the possible variety of rocky ingredients can often add up several different ways to the same average density.

This is an outcome scientists, who would prefer one answer per question, call degeneracy.

If a planet passes in front of its star, so that astronomers can observe the light from the star filtered by the planet’s atmosphere, they can determine the composition of the planet’s atmosphere, which allows them to distinguish about alternative bulk planetary compositions.

“It’s not crazy that astronomers can do this and more people are looking at the atmospheres of these transiting exoplanets,” Fegley says. “Right now, there are eight transiting exoplanets where astronomers have done some atmospheric measurements and more will probably be reported in the near future.”

“We modeled the atmospheres of hot super-Earths because that’s what astronomers are finding and we wanted to predict what they should be looking for when they look at the atmospheres to decipher the nature of the planet,” Fegley says.

Two model Earths

Even though the planets are called super-Earths, Fegley says, the term is a reference to their mass and makes no claim about their composition, much less their habitability. But, he says, you start with what you know.

The team ran calculations on two types of pseudo-Earths, one with a composition like that of the Earth’s continental crust and the other, called the BSE (bulk silicate Earth), with a composition like the Earth’s before the continental crust formed, which is the composition of the silicate portion of the primitive Earth before the crust formed.

The difference between the two models, says Fegley, is water. The Earth’s continental crust is dominated by granite, but you need water to make granite. If you don’t have water, you end up with a basaltic crust like Venus. Both crusts are mostly silicon and oxygen, but a basaltic crust is richer in elements such as iron and magnesium.

Fegley is quick to admit the Earth’s continental crust is not a perfect analog for lifeless planets because it has been modified by the presence of life over the past four billion years, which both oxidized the crust and also led to production of vast reservoirs of reduced carbon, for example in the form of coal, natural gas, and oil.

Raining acid and rock

The super-Earths the team used as references are thought to have surface temperatures ranging from about 270 to 1700 degrees Celsius (C), which is about 520 to 3,090 degrees F. The Earth, in contrast, has a global average surface temperature of about 15 degrees C (59 degrees F) and the oven in your kitchen goes up to about 450 Fahrenheit.

Using thermodynamic equilibrium calculations, the team determined which elements and compounds would be gaseous at these alien temperatures.

“The vapor pressure of the liquid rock increases as you heat it, just as the vapor pressure of water increases as you bring a pot to boil,” Fegley says. “Ultimately this puts all the constituents of the rock into the atmosphere.”

The continental crust melts at about 940 C (1,720 F), Fegley says, and the bulk silicate Earth at roughly 1730 C (3,145 F). There are also gases released from the rock as it heats up and melts.

Their calculations showed that the atmospheres of both model Earths would be dominated over a wide temperature range by steam (from vaporizing water and hydrated minerals) and carbon dioxide (from vaporizing carbonate rocks).

The major difference between the models is that the BSE atmosphere is more reducing, meaning that it contains gases that would oxidize if oxygen were present. At temperatures below about 730 C (1,346 F) the BSE atmosphere, for example, contains methane and ammonia.

That’s interesting, Fegley says, because methane and ammonia, when sparked by lighting, combine to form amino acids, as they did in the classic Miller-Urey experiment on the origin of life.

At temperatures above about 730 C, sulfur dioxide would enter the atmosphere, Fegley says. “Then the exoplanet’s atmosphere would be like Venus’s, but with steam,” Fegley says.

The gas most characteristic of hot rocks, however, is silicon monoxide, which would be found in the atmospheres of both types of planets at temperatures of 1,430 C (2,600 F) or higher.

This leads to amusing possibility that as frontal systems moved through this exotic atmosphere, the silicon monoxide and other rock-forming elements might condense and rain out as pebbles.

Asked whether his team ever cranked the temperature high enough to vaporize the entire Earth, not just the crust and the mantle, Fegley admits that they did.

“You’re left with a big ball of steaming gas that’s knocking you on the head with pebbles and droplets of liquid iron,” he says. “But we didn’t put that into the paper because the exoplanets the astronomers are finding are only partially vaporized,” he says.

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54 Responses to Vaporizing the Earth

  1. George V says:

    “Fegley says. “Right now, there are eight transiting exoplanets where astronomers have done some atmospheric measurements and more will probably be reported in the near future.”

    OK, so you got this star, and a large planet that’s still pretty small in comparison to the star, and it’s a bajillion miles away and you can measure the compounds in the atmosphere?!?!? That is impressive!
    George V.

  2. Where is my illudium Q-36 explosive space modulator?

  3. Dodgy Geezer says:

    …“We scientists are not content just to talk about vaporizing the Earth,” says Bruce Fegley, professor of earth and planetary sciences at Washington University in St. Louis, tongue firmly in cheek. “We want to understand exactly what it would be like if it happened.”…

    I guess it would be hot. Can I have my professorship now?

  4. Chris B says:

    “Raining acid and rock.” Sounds like a Prince concert in the 70′s.

  5. The wording that’s used is still stocky
    The “super-Earth” term is too cocky
    I suggest with a twinkle:
    Gas giant? Bullwinkle
    And hard inner planets are Rocky.

    ===|==============/ Keith DeHavelle

  6. Bob says:

    Who is Bill McKibben?

  7. Chuck L says:

    David Thomas Bronzich says:

    August 3, 2012 at 4:09 pm

    Where is my illudium Q-36 explosive space modulator?
    ________________________________________________

    Awesome! I’m a huge Marvin fan!

  8. Jenn Oates says:

    I am laughing so hard because I just downloaded those books to my iPad kindle app to have something to read on my various flights. Vogons. Bwahahahaha!

    Okay, what was this post about again?

    :)

  9. Ally E. says:

    This is going to lead to CAGW, right? I just know it. Somewhere down the track, they’re going to say, “See? This is what will happen if we don’t stop emitting CO2 and water vapour. Human civilization will lead to Earth’s vaporization!” It’s another scare in the making, they are not finished with us yet.

  10. “We want to understand exactly what it would be like if it happened.”

    “There was a terribly ghastly silence.
    There was a terribly ghastly noise.
    There was a terribly ghastly silence.” – Douglas Adams.

  11. Mike McMillan says:

    That was a ‘hyperspace bypass,’ not a ‘hyperspatial express route’ and the answer was ’42′

  12. @ Jenn Oates.

    Is this for a re-read or your first time?

    If I were running a university, I would set policy that a prerequisite for taking any course involved in computers – in any way! – would be knowledge of the saga of “Deep Thought”, the second greatest computer in all of space-time.

  13. Chuck Dolci says:

    Let’s be honest. Who really cares about planets vaporizing? Why do universities spend money on this kind of nonsense? If it happens there is nothing we can do about it, we won’t be around to worry about it after it happens. What do they (we?) expect to gain from this. Will they write and distribute a pamphlet “Ten things you should do when the planet starts to vaporize.” or “How to survive in a post vaporized world.” What useful information comes out of this research?

  14. “…vast reservoirs of reduced carbon, for example in the form of coal, natural gas, and oil.”

    Why did they not mention the vastly larger reservoirs of reduced carbon in the form of limestone, dolomite, marble and chalk?

    However, given that vast amounts of methane exist on Saturn, Uranus and Jupiter and many moons in our solar system, why would the exoplanet simulations they did not consider have methane (natural gas) on planets that never had life?

    It seems to me that if their simulations did not consider abiogenic methane generation, then they most likely forgot about some other things in their models as well. I doubt it that their models are theoretically correct and hope they don’t do climate simulations for Earth.

  15. gringojay says:

    De’ My-tee’ Arrow a troo’ calypso singing mon’ wrote about dis’ first. Eye’n’eye (we) knows how be his Monserrat island home then blew she sef’ up later on:
    “Me mind on fire, me soul on fire
    Feelin’ hot hot hot
    Party people, all around me
    Feelin’ hot hot hot
    So we can boom boom boom boom
    Yeah arroom boom boom boom
    See people rockin’ yeah people chantin’
    Feelin’ hot hot hot
    Keep up the spirit come on let’s do it
    Feelin’ hot hot hot”

  16. Mr.D.Imwit says:

    Unbelievable,It seems that most modern science is just a big scam.
    Maybe we should all start writing our fantasies for big grant money.

  17. Fred says:

    Because most of our future scientist’s are in training to become science fiction writers Oh i forgot our climate scientists have already done this.(sark off)

  18. Smokey says:

    gringojay,

    That brings back memories. Here’s Buster Poindexter with the global warming tune. IMHO, a better re-do of the Arrow original.

  19. David A. Evans says:

    Why did this come immediately to mind?

    DaveE.

  20. Gunga Din says:

    Two questions:
    1. Does Super Earth have a Super Moon?
    2. Are it’s ice caps melting?
    (Ok, three questions.)
    3. Did Superman really come from Super Earth?
    (Ok, four questions.)
    4. Would Super Beano prevent Super Earth from becoming a Gas Giant?

  21. Brian H says:

    Happens that the only Earth-size planets found and studied much to date are the close-in ones that line up with us and eclipse their star’s light slightly, and with very short orbital periods so the ‘flicker’ and (possibly) the stellar gravitational wobble can be detected. Those are close-in hot; the further-out cool ones will be detected later (a few candidates are awaiting verification). That’s where the atmospheric chemistry and heat budgets will get really interesting. There will be more than one “data point”!

  22. Gary Hladik says:

    Rather than calling these planets “Earth-like” which they’re not, or “super-Earths” which they’re also not, why not call them “Vulcans” after the planet once predicted inside Mercury’s orbit?

    http://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet)

  23. Gunga Din says:

    So the real danger is that greenhouse gases will all be emitted at the same time from the same side of the planet that is facing away from the Sun thus moving us into a lower orbit where Hansen’s fears of Earth’s atmosphere becoming like Venus may then be realized.
    Hmmm …. that’s more plausible than what he’s said so far.
    (Maybe Super Beano is the answer afterall!)

  24. Mike Wryley says:

    “We want to understand exactly blah blah blah”,,,

    I am all for scientific inquiry, especially if it’s on your own dime, but we don’t understand exactly much of anything even when it’s less than 13,000 miles away, let alone light years. One has to ask if we really have the luxury of allocating resources to this kind of quasi scientific auto erotic exercise.

  25. RockyRoad says:

    Bob says:
    August 3, 2012 at 4:50 pm

    Who is Bill McKibben?

    Who cares who is Bill McKibben.

  26. Reblogged this on thewordpressghost and commented:
    Amazing.

    We are reverse engineering what we expect to find in alien planets (exo-planets).

    Our scientists are using computer models to ‘vaporize’ earth to see what they expect exo-planets to look like.

    I think we need to write a sci-fi about a couple of these planets.

    What would we call the series?

    Ghost

  27. björn says:

    I cannot help it , but this posting fired a mental image in my brain somwhere , showing climate model progams spewing out of pentabytes of vogon poetry that the climacognosenti could/would then bring to the taxpayer financed international brouhas in nice warm places with good beaches that are so popular among them , to hold vogon poetry recital competition instead of climate “bovine feces” sessions , that way the worst performance should and would really be legitimately entitled to the top marks. :-))) /sarc

  28. Brian H says:

    björn says:
    August 3, 2012 at 9:41 pm

    model progams spewing out of pentabytes of vogon poetry

    /sarc

    Vogon poetry is so deadly that maybe you were thinking of “pogroms”? ;)
    But since there are no such numbers as “pentabytes”, that zeroes out the threat.
    Petabytes, on the other hand …

  29. Gunga Din says:

    TheWordpressGhost says:
    August 3, 2012 at 9:14 pm
    Reblogged this on thewordpressghost and commented:
    Amazing.

    We are reverse engineering what we expect to find in alien planets (exo-planets).

    Our scientists are using computer models to ‘vaporize’ earth to see what they expect exo-planets to look like.

    I think we need to write a sci-fi about a couple of these planets.

    What would we call the series?

    Ghost

    =====================================================================
    “Gone with the Wind”?
    “Going with the Wind”?
    “Lava Rocks Keep Falling on my Head”?
    “The Air in Back, A Hansen’s Tail”?

  30. Gail Combs says:

    And my Tax dollar is paying for this crud?

  31. bluejohnmarshall says:

    I doubt if these exotic planets would have silica rich continental rocks which earth has in abundance due to differential melting of basalt crust. this needs liquid water, to lower the rock melting point and increase melting range to cause the differentiation, which these planets would not have.

  32. Kelvin Vaughan says:

    Mr.D.Imwit says:

    August 3, 2012 at 6:02 pm

    Unbelievable,It seems that most modern science is just a big scam.
    Maybe we should all start writing our fantasies for big grant money.

    I’m working on it already. Methane tankers transporting methane to the earth in the grip of a future ice age from Saturn. And in the reverse direction carrying CO2 back to Saturn.

    Investors welome!

  33. J.Hansford says:

    So….. The street lights on these planets would be melted…. Yes? ;-)

  34. Bill Tuttle says:

    Brian H says:
    August 3, 2012 at 10:02 pm
    Vogon poetry is so deadly that maybe you were thinking of “pogroms”?
    ;)
    But since there are no such numbers as “pentabytes”, that zeroes out the threat.

    Actually, “pentabytes” describes the topography. Vogon digits have length, width, depth, and not only extend into time, but the Fifth Dimension, as well – which is the real reason McCoo and Davis left the group in 1975…

    Ummm, whut?

  35. commieBob says:

    Chuck Dolci says:
    August 3, 2012 at 5:47 pm

    … What useful information comes out of this research?

    Gail Combs says:
    August 3, 2012 at 10:41 pm

    And my Tax dollar is paying for this crud?

    In terms of finding practical applications, most basic research is worthless. The trouble is that we can’t tell what is going to pay off.

    I know one scientist who worked at the bleeding edge. Researchers all over the world were beginning to use the techniques he developed. Then, one day late in his career, someone else published work that took the whole field in a different direction. So, was his career wasted? Well, one of the scientists who trained in his lab went on to win the Nobel Prize.

  36. Mike Wryley says:

    Nobel Prize,,
    now there’s a mark of distinction

  37. banjo says:

    Wheeee! We`re doing hitchhikers…it`s ok…i`m a hoopy frood who knows where his towel is!
    THIS is marvin.

    and vogon poetry ..lovely

  38. Reed Coray says:

    George V says: August 3, 2012 at 4:09 pm

    “Fegley says. “Right now, there are eight transiting exoplanets where astronomers have done some atmospheric measurements and more will probably be reported in the near future.”

    OK, so you got this star, and a large planet that’s still pretty small in comparison to the star, and it’s a bajillion miles away and you can measure the compounds in the atmosphere?!?!? That is impressive!

    George, ye of little faith. It’s simple. Their bristle cone pine trees are going to teleconnect with our bristle cone pine trees, and then it’s a simple matter of analyzing tree ring patterns. Wait, how “skeptical” of me. Bristle cone pine tree rings record temperature not atmosphere content.

  39. Gordon Richmond says:

    In response to Walter H Schneider, who asks:
    “Why did they not mention the vastly larger reservoirs of reduced carbon in the form of limestone, dolomite, marble and chalk?”

    Perhaps because the carbon in those rocks is oxidized, not reduced? It does, after all, occur as the carbonate ion, CO3.

  40. Gregory Smith says:

    RE: TheWordpressGhost says:
    August 3, 2012 at 9:14 pm

    World building is not just for scientists. It has a long tradition in science fiction.

    Michael McCollum did the boiled earth years ago in “The Clouds of Saturn”.

    http://scifi-az.com/saturn2.htm

  41. ferdberple says:

    Walter H. Schneider says:
    August 3, 2012 at 5:52 pm
    “…vast reservoirs of reduced carbon, for example in the form of coal, natural gas, and oil.”
    Why did they not mention the vastly larger reservoirs of reduced carbon in the form of limestone, dolomite, marble and chalk?
    =============
    What is required to change water and limestone into hydrocarbons? Iron, heat and pressure. All of which are found in vast quantities within the earth.

    However, this would mean that natural gas for example is not a fossil fuel, and thus should be relatively plentiful. That as you drill deeper, discovery rates should remain relatively constant.

    The bottom of the Grand Canyon in the US is 1 mile deep, and rocks at the bottom are about 2 billion years old. Fracking is finding gas 3 miles deep.

    Little wonder that the US government desperately want’s to limit access to this gas.

  42. Andrew30 says:

    “LOS ANGELES – A team of physicists at UCLA announced yesterday that they have made a major scientific breakthrough with the discovery of an important new sub-atomic particle. This was the team’s eighth major particle this month, giving them a three-particle lead over MIT.

    “These particles are very difficult to detect, even with the aid of enormous federal grants,” said Head Physicist Dr. Ernest View-Finder. “But we definitely saw an important new one. At least I saw it, and Dr. Hubbleman here thinks he did, too.” Dr. Viewfinder said he could not show this particle to newsmen because it was ‘resting’.”

    I’m wondering if the physicists are pulling some kind of elaborate scam here. I’m starting to wonder if they don’t sit around their $23 million atomic accelerators all day, drinking frozen daiquiris, and shrieking “There goes one now!” and then laughing themselves sick.

    Dave Barry
    (Dave Barry’s Greatest Hits: ISBN 0345419995)

  43. Walter Schneider wrote:
    “Why did they not mention the vastly larger reservoirs of reduced carbon in the form of limestone, dolomite, marble and chalk?”

    I think you mean oxidised carbon? CaCO3, MgCO3 etc. Reduced carbon makes hydrocarbons.
    Actually the quantities of coal/oil/gas deposits almost certainly exceed the carbonates.
    The wonder of photosynthesis is that it reduces carbon dioxide to carbon releasing free oxygen.
    Since this has been going on for nearly 3000 million years on earth the reserves of carbon/hydrocarbons is absolutely massive. All the oxygen now trapped in iron ore originally came from CO2 in the early atmosphere, leaving the corresponding amount of reduced carbon dioxide – coal/oil/gas – somewhere to be found. At a rough estimate there is still around one billion gigatonne to be found – minimum. We’re not going to run out anytime soon!

  44. tckev says:

    So they’re saying that as the earth’s crust melts then all the constituent parts vaporize then rain down again in a sort of Brownian motion way?
    The same Brownian motion producer is at the core of Douglas Adams’ the Infinite Improbability Drive. S.S. Heart of Gold, the first prototype ship to successfully use the revolutionary Infinite Improbability Drive.
    These Super-earths therefore are not just planets outside our solar system (exoplanets) but they must be the much sought after Infinite Improbability Drive powered super spacecraft.

    Be afraid, be very afraid as the bending of the normal laws of physics, logic, and humor may ensue.

  45. Jenn Oates says:

    Steven, I’ve read all of them many times. :)

  46. Entropic man says:

    Those intrested in Earth’s future history might like to read this.

    http://news.nationalgeographic.com/news/2007/09/070914-red-giants.html

  47. Louis Hooffstetter says:

    Prince concerts raining acid and rock?
    Hitchhiker’s Guide to the Galaxy?
    Hot, Hot, Hot by Arrow & Buster Poindexter?
    This tells me more about the folks who read WUWT than the scientific threads.
    (It tells me we need to get together and party!)

  48. LazyTeenager says:

    Chuck Dolci on August 3, 2012 at 5:47 pm
    Let’s be honest. Who really cares about What useful information comes out of this research?
    ———-
    Answer:that Chuck thinks that leaving the trees to live in caves was a bad idea.

  49. derfel cadarn says:

    As some who believes that all knowledge is relevant I cannot fathom the expenditure of time and assets to acquire this information .what does one do with this information, as no one would be here from humanity to care.

  50. It seems to me that with respect to petroleum the science of abiogenic hydrocarbon generation is at best not settled, but perhaps settled with respect to methane (or wrt the majority of natural gas reserves):. http://en.wikipedia.org/wiki/Abiogenic_petroleum_origin#Evidence_of_abiogenic_mechanisms

    Nevertheless, when it comes to “fossil” fuel, what about this, “Fossil Fuel is Nuclear Waste”? http://www.canadafreepress.com/index.php/article/28111

  51. Dave says:

    Bob says:
    August 3, 2012 at 4:50 pm
    Who is Bill McKibben?

    Bill McKibben, Al Gore, Michael Mann are all living proof that the Three Stooges had kids.

  52. susankatzkeating says:

    I’ve been going through the archives for several months, and reading the comments with fascination. I’m no Luddite, but the scope of commentary here is painfully beyond my level of comprehension. I continue to be enlightened. Thank you for the insights.

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