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Extrasolar Planet Could Harbor Life
BlueMorpho writes with a link to a Space.com article about a recently discovered extrasolar planet that may be able to harbor 'life as we know it.' Orbiting around the star Gliese 581 is a small rocky ball that might have the same liquid ocean and drifting continent configuration we're familiar with. The find may be unique in all of space exploration as this planet appears to be within a habitable band of temperatures for life, and is categorically not a gas giant. "The bottom line is exciting ...The conditions for life could be there, but is life itself? As yet, there's no way to know unless the planet has spawned beings that are at least as clever as we are. As part of the SETI Institute's Project Phoenix, we twice aimed large antennas in the direction of Gliese 581, hoping to pick up a signal that would bespeak technology ... Neither search turned up a signal."
hey kids! Exciting news a planet could have life - assuming it has an atmosphere. And if it does have that atmosphere, it doesn't overheat the planet through greenhouse heating. And oh yeah, all we know about it is its orbit and mass. And it almost definitely doesn't have life. Aren't you excited?
When the media flogs "science" stories like this, full of marginal ideas that probably aren't true are we just conditioning the public to ignore actual science as pie in the sky crap? Or does the break from Paris Hilton news stories have some tangible benefit to educating society at large?
I have wondered how well we could adapt to even an Earth like planet in terms of infectious agents like bacteria and viruses. Would we just have to accept higher mortality rates until our immune systems adapted over time?
The medical science and technology might the easy part compared to interstellar travel though.
The planet is so close to the star that it's likely tidally locked so that only one side faces the sun and the other side is in eternal night. The temperature differential between the hot day side and the cold night side might cause the border to be under constant storm activity.
A "year" where the planet rotates around the star is only 13 days. If tidally locked, a "day" is the same amount of time.
The same tidal forces would also make any large oceans on the surface prone to immense tides. The strong tides may also result in more tectonic activity than on Earth.
A planet of Earthlike mass in the habitable band would almost certainly have to have an atmosphere of some kind. Whether or not that atmosphere is breathable or not is another question altogether. From that distance, Venus or Mars would look pretty good to extraterrestial terran planet hunters. Masswise Venus is a near twin of earth but the surface conditions are straight out of Dante's Inferno. Mars is a shade too light to hold on to a thick O2 atmosphere and is basically a cold rusty desert. My guess is this place is apt to be more like Venus or Mars than Earth. Any chance we could talk Goldilocks into planet hunting?
1. Our sun's positioning in this galaxy is basically perfect. We're between two of the 'arms' of the milky way. Meaning we're nestled safely away from the gravitational chaos of other stars that may want to rip us out of our orbit around the center of our galaxy. So that rules out many places in our galaxy. Not saying there isn't a chance. I'm just saying that theoretically, the planets in there may be screwed some time in the future. Most other galaxy styles don't have a 'safe harbor' like this.
2.Earth itself has so many favorable factors for it that it is astounding. The tilt of our axis makes for an optimal environment for life across our whole planet. I remember reading that many astrologers estimate that just a half a degree either way and we'd have much larger ice caps or a band of uninhabitable desert. Our elliptical, almost circular, orbit keeps us in the most comfortable spot. A million miles either way and we'd be toastier or colder. Life could still exist, but it would be less than 'ideal'.
As I understand it, our ferrous core spinning at slightly different speed creates our Van Alen Belts to protect from solar wind.
We have an asteroid belt that has protected us from undoubtedly billions of asteroids over the millennial of Earths existence.
Our tidal locked moon pulls on the oceans causing the Earth to continue spinning at a proper speed to maintain life.
How' that? When you consider all this, and the probabilities being of this happening elsewhere (or just 'enough')... you can pretty well give up hope. But there isn't any fun in that! I'm all for looking for hospitable planets. This universe is fascinating. What a waste to not explore?!
This sig isn't original enough, it's time to come up with something witty...
The answers are, respectively, yes, and no. Though we have made a heck of a lot of noise at other frequencies, and the earliest of those signals are very roughly about 100 light-years out by now. They would be extremely weak and difficult to detect, though with a large enough space-based antenna system, it is certainly doable if they listen in the right direction. Signals that have gotten about 50 light years out are much more powerful; they've reached fewer stars, of course.
I suspect that our "window" of using RF transmissions through the air will close within another century or so. There are better, more reliable things available to us such as fiber; almost incomprehensibly higher bandwidth by virtue of one fiber being able to lie next to another, not so easy when using RF, better availability, much more difficult to interfere with, more efficient in terms of energy required in use... RF just doesn't make a huge amount of sense for broadcast, and this is becoming more so every day. And I say that with a certain degree of regret, being an extra-class ham radio operator who grew up with the romance - no, really, I'm serious, romance! - of radio signals fading in and out from all over the world.
It is what we'd do - we're not doing it for political reasons, not scientific or technical reasons. It has been proposed over and over that we broadcast; and has been turned down every time. The question is, do we want to invite visitors? It is one thing to be curious to see if you have neighbors, and to learn the answer without disturbing them or letting them know we're here; it is entirely something else to let them know we're here, or to invite them over - as unlikely as that seems given what we know of physics today. Considering that it is unlikely, it would be all the more intimidating if someone from the Sirius system, just to pluck one out of a hat, heard our signal and a day after they heard it there, they showed up here. The question is, what would they show up with if their physics are that good? All they really need is the ability to shove a few large rocks in our direction and they could go home snickering about those silly primates that used to live on Sol 3... that concerns a lot of people. Some earth species are quite aggressive and territorial, and man is one of them. Looking at our own behavior, it doesn't seem too conservative to think that the same might apply to someone else. So the politics are knotty.
I've fallen off your lawn, and I can't get up.
I think you need to recheck some of your facts.
Our solar system moves in and out of the spiral arms as well as up and down through the galactic plane. We go through the galactic plane about every 35 million years, and through the spiral arms about every 100 million years. Some postulate that these timescales coincide with various mass extinctions that occurred.
The axial tilt of the Earth changes all the time. The tilt angle varies between 22 and 25 degrees over a period of about 41000 years. There is also precession of the orbit that happens on a 22000 year timescale. The changing tilt angle changes the severity of the seasons (length of seasons, ice ages, etc.), but it doesn't have anything to say about whether the planet could harbor life.
There isn't anything magical about our molten core and magnetosphere. We usually expect large rocky planets to have them, so we find it unusual if a planet doesn't have a magnetosphere.
I wouldn't say that the asteroid belt has protected us. The asteroid belt is basically a planet that either didn't form, or didn't survive. Its existence is probably one of the biggest threats to our survival on this planet. It is a race to see whether a large asteroid or comet hits our planet and wipes us out. Nobody doubts that it will happen again in the future; we just don't know when it will.
The Moon actually causes a drag on the planet that is slowing down the Earth rotation. I don't recall hearing what an ideal rotation rate for the Earth is to sustain life.
Once one gets their head around how many stars there are in just our own galaxy, many people consider it a given that there is life all around in the galaxy. Even if you take the most pessimistic odds for life to develop, once you multiply that by the number of stars out there it would seem to be very likely. The most famous statement of this is the Drake Equation. Of course, once you consider the extremely large distances between any two stars it is easy to come to the conclusion that all this life will not come in contact with each other (the intelligent life, that is).