Skip to comments.Cosmic Crashes May Give Habitable Planets the Boot
Posted on 08/29/2011 4:02:20 AM PDT by SunkenCiv
Long-ago collisions between clouds of gas and dust could explain why many alien solar systems have planets with strange, highly tilted orbits -- and why habitable worlds may be rare in the universe, a new study suggests.
Newly forming solar systems may be jostled by interactions with nearby clumps of matter, leading to systems in which alien planets have dramatically tilted orbits and the smaller (and potentially habitable) worlds are ejected, according to the study...
Most of the planets in our own solar system, including Earth, have relatively circular orbits and are lined up along a plane that isn't tilted much from the sun's equator. They also orbit in the same direction around the sun as our star spins.
But many other solar systems are not so neatly ordered, harboring planets that move in the opposite direction of their stars' spin on highly tilted orbits. The new study offers a possible explanation for these seemingly irregular traits.
Planetary systems coalesce from clouds of dust and gas that collapse into a rotating disk under the influence of gravity. Planets grow from clumps of matter within these protoplanetary disks, which have young stars at their centers.
Using computer models, the researchers showed that protoplanetary disks can become considerably tilted if they encounter another nearby cloud of material and suck in some of its mass. These collisions can also reverse the disks' spin, leading to the odd orbits seen in many alien solar systems today...
(Excerpt) Read more at space.com ...
This artist's concept shows a very young star encircled by a disk of gas and dust, the raw materials from which rocky planets such as Earth are thought to form. CREDIT: NASA/JPL-Caltech
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There seem to be an almost infinite number of variables that allow life to exist as we understand it. Every time someone adds a variable, we see a smaller percent of that potential hundred bazillion planets where anyone will discover ETs.
Didn’t the Star Trek movies refer to this as “terraforming”?
I think far too many assumptions are made about habitability. Humans exist in a fairly narrow band of habitable conditions but some life could be very tolerant.
Its entirely possible that life could exist on the earth if it were as close to the sun as venus or as distant as mars. It wouldn’t be exactly the same as us.
There are innumerable variables that could be taken into account and virtually all of them are possible. Maybe a planet orbits a star in a cluster where the other stars provide enough cumulative heat for earth similar life.
The general rule of thumb is that life needs liquid water.. within that range, life has been found in Arctic areas and volcanic vents. Intelligent life (tool users) would require a more precise environment. A water world would likely prevent life from using fire, a key ingredient to advancing a society. Material for easily fashioning primitive tools is another. Imagine if plant life was only grass and moss. You couldn’t make a crude spear or axe.
I hate the word "many" in any scientific description. Wikipedia says "As of February 2011, NASA's Kepler mission had identified 1,235 unconfirmed planetary candidates associated with 997 host stars". Is "many" ten of them? One hundred? One thousand of the 1235?
Politics has the same issue. Declare that "many" people have a problem (even if it is a dozen in the whole country) and create a multi-billion dollar program to fix that problem.
I tend to take a different tack on intelligent life.
The last thing we need to find is intelligent life. We need life we can eat. As it is the vegans are already afraid we’ll be carnivores in space.
That’s a good point, often missed by many. Extrapolation is pretty difficult when you are going off an example of one.
I wouldn’t count on being able to eat anything we find. Your biology would likely have more in common with a tree, than with any alien plant or animal. Makes the nutritional value of any alien life doubtful.
A biologist might know more about that though.
There’s been a puzzling amount of writing about how this planetary system is so much different from the extrasolar planetary systems detected so far — that’s clearly because the only detectable ones are the ones that look weird compared with ours.
Thanks, and I agree — but also, conditions on Earth have changed, rapidly, so many times, that the foolish idea that everything has been uniformly and barely changing is egregiously in error.
I would love an astronomer to figure out how far away our solar system could be detected using our best equipment. The first planet detected would be Jupiter, but would its 12 year revolution period be too slow to provide a Doppler shift to the sun’s light?
I think on this sort of thing and build planetary systems in my head at night to deal with insomnia. The possibilities really are as limitless as imagination.
One of my favorite thoughts is about a planet in close orbit with a white dwarf. The planet tidally locked so one side faces the dwarf all the time but the dwarf/planet system orbit a large star.
The planet would actually have a day night cycle on the “dark side” but it would be due to it’s orbit around the dwarf star.
The capabilities of current equipment have been enhanced, but also used in new ways to improve detection; newer stuff has improved detection; orbiting observatories have been, and will continue to be used to extend reach. Analogously, when SETI listening began about 50 years ago, it was calculated that the strongest then-extant radio transmitter could be picked up by the strongest then-extant receiver at a distance of something more than ten light years, which restricted the number of targets. Within just a few years the sensitivity improved to extend that range fourfold, which was, what, 64-fold increase in the volume of space.
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