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Our future, our universe, and other weighty topics


Friday, June 13, 2014

The 5 Most Inexplicable Planets

Scientists have learned more and more about planets by studying them with instruments such as the Kepler Space Telescope. But in five different cases they have found results that leave them baffled – planets that either shouldn't be there or shouldn't be the way they are. Below is a list of the five most head-scratching planetary mysteries.

Gliese 436 b

Gliese 436 b is a Neptune-sized planet orbiting a red dwarf star. The planet orbits so close to its star that the planet's temperature is estimated to be 439 degrees Centigrade. But scientists estimate that most of the planet is solid water – some kind of weird solid water that doesn't melt even at very high temperatures.

Scientists also say the planet has more carbon monoxide than it should have. The biggest mystery about the planet, however, is that it apparently has about 7000 times less methane than it should, according to models of planetary formation.

The Pisces Puzzler

GU Piscium b (also known as GU Psc b) is a planet that orbits its star at a distance of 2000 times the distance between the Earth and the Sun. By comparison, in our solar system the dwarf planet Pluto orbits at a distance of about 32 times the distance between the Earth and the Sun.

Scientists are baffled by how such a planet could have formed. The prevailing model of planetary formation holds that planets and a star form from a single disk of gas and dust. It's hard to imagine such a disk originally extending 2000 times the distance between the Earth and the Sun. The planet GU Piscium b takes about 163,000 years to orbit its star.

Kepler 10c

Kepler 10c is a recently discovered planet that has 2.3 times the Earth's radius, and about 17 times the Earth's mass. According to planetary formation models, a planet with that mass and radius should be a gaseous planet similar to Neptune. But scientists say that Kepler 10c is actually a rocky planet – a super-Earth bigger than the maximum size of a rocky planet, according to previous scientific estimates. Scientists had a previous notion of the “most massive super-Earth possible,” but Kepler 10c is a super-Earth much bigger than that.

Kepler 10C
  My guess about what it looks like on Kepler 10C

Scientists conclude that the solar system which Kepler 10c formed from is about 11 billion years old, only a few billion years younger than the universe. According to prevailing theories, there needed to be quite a few generations of stars before there could be enough heavy elements for rocky planets to form. So how could a rocky planet have formed so early? Scientist Dimitar Sasselov says, “Finding Kepler-10c tells us that rocky planets could form much earlier than we thought.” Could the universe have been on an accelerated development schedule, like some bright kid who skips a grade or two in school?

TrES-4

TrES-4 is a planet about 1.7 times the size of Jupiter. “TrES-4 is way bigger than it's supposed to be," says scientist Georgi Mandushev. "For its mass, it should be much smaller. It basically should be about the size of Jupiter and instead it's almost twice as big."

Kepler 78b

Kepler-78b is a planet orbiting the star Kepler 78, a G-class star like the sun, located about 400 light-years away. The strangest thing about the planet is the location of its orbit. The planet orbits its star at a distance of about 900,000 miles, which is about the diameter of the sun and other G-class stars. This is an orbit which places the planet more than 30 times closer to its sun than the planet Mercury is to our sun. The planet is so close to its star that it must be a kind of lava world too hot for life.

Scientists are baffled by how a planet of this size could exist in this orbit, and the Science Daily article on the discovery is entitled Lava World Baffles Astronomers: Planet Kepler-78b 'Shouldn't Exist.'  The article says: “When this planetary system was forming, the young star was larger than it is now. As a result, the current orbit of Kepler-78b would have been inside the swollen star.” It then quotes astronomer  Dimitar Sasselov as saying this about the planet: "It couldn't have formed in place because you can't form a planet inside a star. It couldn't have formed further out and migrated inward, because it would have migrated all the way into the star.”

Earth?

That's all for my list of the five most inexplicable planets, but perhaps I should add a sixth: our own planet Earth. For this is the planet where there has occurred two all-but-inexplicable things we have never witnessed on any other planet: the origin of life and the origin of advanced consciousness.

As discussed here, the origin of life seems nearly inexplicable because a very high degree of sophistication must be reached before any Darwinian biological evolution can begin. You apparently need a genetic code and self-replicating molecules before any biological evolution can occur, but how could those have appeared? Scientists are trying to create models of “chemical evolution” to bridge this gap, but it's not at all clear that the concept of evolution can be carried over in an adequate and meaningful way from the world of biology to the world of chemistry.

The origin of advanced consciousness seems nearly inexplicable because humans have so many subtle mental abilities that are hard to explain by evoking natural selection: things such as spirituality, aesthetic appreciation, language abilities, moral impulses, math abilities, philosophical abilities and so forth. Quite a few of these are abilities or traits that have no obvious benefit in allowing a human to survive until reproduction, and they therefore seem to be things that are very hard to account for under any explanation of natural selection in the “survival of the fittest” sense, as I discuss here. This does not suggest that evolution doesn't occur, but may suggest that it can't explain everything about the human mind.

We might say, therefore, that none of the astonishing things discovered on other planets is as astonishing as what we know has happened on our own planet.

My own view is that the known laws of nature and features of nature are probably inadequate to explain the appearance of life (and particularly intelligent life) on our planet, and that we may need to postulate the existence of additional undiscovered features of nature that could help account for such phenomena. See other posts on this blog (for example, this one) for my thoughts on this topic.