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Odds Favor Discovery of Earth-Like Exoplanet in 2013
Earth-like exoplanets have gotten a lot of attention in the last few years; it's exciting to think that there's life — or even just life-sustaining conditions — on planets other than Earth, whether near by (on Mars) or much farther away (orbiting Vega). Projects like NASA's Kepler, and the ground-based HARPS, attempt to spot planets outside our solar system of all kinds. These exoplanet discoveries have been ramping up lately, and so has sorting of the discovered planets by size and other characteristics; the odds are looking good, say astronomers quoted by Space.com, that an Earth-like planet will be found this year. Abel Mendez runs the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, and UC Berkeley astromer Geoff Marcy looks for planets as part of the Kepler team; they explain in the article why they think 2013 is an auspicious one for planet hunters.
OTOH, ya' never know. Some theory that's still relegated to the sci-fi class might get proven doable, warping space-time and "riding the wave" looks to be possible. Or,aliens could land and gift faster than life travel to us (if we prove 'worthy' of it, or we could beat 'em up and take it from them!).
Today we have 'impossible' Star Trek tech in our pockets. And amazing tech is coming down the pike in our near future. But to say "it's never gonna' happen", IMO, is a rather short sighted opinion, not unlike past pessimists who couldn't see past their own closed off reality.
When I was a kid, walking on the moon was 'impossible', never going to happen.
Now as an adult, walking on the moon is 'impossible', never going to happen again.
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
the heavens favor the believers.
Actually, we have no idea how tilted the odds are against life. What we do know:
- On the conditions that existed on Earth in its early history, forming organic compounds was more-or-less inevitable.
- Life exists on Earth under really unusual conditions, like highly acidic underground lakes.
- There's some evidence (but no conclusive proof) of there once having been microbes on Mars.
It's quite possible life is rare. It's also quite possible life is common. We simply have no way of knowing one way or the other right now.
I am officially gone from
Getting to other stars isn't actually terribly difficult, as far as we can currently tell. Only getting there quickly presents a problem. Build a large, self-sufficient "space station"/world-ship, accelerate it to say 0.1% of light speed (only about 20x faster than Voyager 1), and then wait for a few thousand years until it reaches it's destination. Sure, accelerating it with current technology gets really expensive really quickly, and it'll be the distant descendents of the original crew who reach the destination, but the only real difficulty is creating a long-term viable self-contained ecosystem. And considering that the one serious attempt we've made, Biosphere 2, was actually remarkably successful for a first attempt, we could probably have that problem licked within a few decades if we really wanted to. All we'd need is some sufficiently motivating reason to do so, which is where the real problem lies.
Quite similar to getting to the moon actually - basic rocketry technology has been around for almost a thousand years, but it wasn't until we got into a technological pissing contest (aka The Cold War) with Russia that we actually got off the planet and eventually to the Moon. We've never returned because, well, why would we? There's nothing there worth the expense of the trip, and until we reach a point where its tactical or strategic value is worth the expense it's only the dreamers and visionaries that appreciate its value, and sadly they don't control near enough wealth to make it happen.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
That is probably the larger contributor, but even without the solar wind it's atmosphere would likely be much thinner - it only has ~1/3 the surface gravity, and it falls off much faster with altitude. It's smaller size probably also contributed significantly to faster cooling and the associated shut-down of its magnetic dynamo subsequent exposure to the solar-wind. Evidence suggests that Mars did in fact once have a substantial magnetic field. Getting a massive chunk of (presumably) cold material embedded in it's mantle probably didn't help things either - Olympus Mons appears to be the result of the shockwave from a truly massive impact on the opposite side of the planet. Lets all thank Mars for taking the bullet for us, it would've made "the dinosaur killer" look like a pea-shooter in comparison.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
But the real question is what their IPv6 address range is. We need to know now since packets will take so long.
now we need to go OSS in diesel cars
Not really - the atmosphere is an incredibly thin skin around a rocky planet and it's composition can only be detected by the use of *extremely* sensitive instruments. Imagine passing a pea in front of a street light several miles away - it'll be *far* easier to detect the shadow of the pea than the condition of its skin.
And actually that's a rather obsolete method for detecting planets - you can only detect those whose orbital plane happens to intersect the Earth - a tiny percentage since the alignment is more or less random. More modern techniques detect planets via the wobble they introduce in the motion of their parent star - for example our sun actually orbits a point lying about 1/2 to 2 solar radii away from its center - the barycenter (center of mass) of our solar system, which constantly changes as the massive outer planets move through their orbits. Our own planet introduces a much smaller (since we're far closer and less massive) but higher frequency (since our year is much, much shorter) wobble as well. By detecting similar wobbles in other stars we can make a good estimate about the masses and distances of its planets, and the planet doesn't have to pass directly between its star and us to be detected, allowing us to detect far more planets.
Analyzing atmospheric composition is more challenging, and I believe current techniques are limited to planets that pass directly between us and their star - essentially a planet with no atmosphere will dim the light slightly as it blocks a tiny percentage of it, an atmosphere will also introduce a *very* tiny spectral shift since some of the starlight that reaches us will have passed through the planet's atmosphere and been partially absorbed based on it's chemical composition. Theoretically a similar technique could be used for out-of-plane planets by analyzing reflected light, but our current instruments aren't nearly sensitive enough to distinguish between the miniscule amount of light reflected from a planet and the raging inferno of its star. Even if we could, it would likely be extremely difficult to distinguish between the spectrum shift introduced by the atmosphere and the shift introduced from surface reflection.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
I'm trying to, asshole. Why do you think I'm asking a question?
"Well, good luck finding a judge that doesn't run a bestiality site."
What I think is so cool about these discoveries is, in the words of astronomer Steve Vogt, "the emerging view that virtually every star has planets". Think about this for a while. Look at all the stars in the sky, and imagine every single one of them having a planetary system. Suddenly it doesn't seem to much of a stretch thinking some of them might be habitable, or even harbour some kind of life.
In my eyes this fact, if it gets confirmed by subsequent studies, is the biggest discovery about the universe since the theory of relativity. When I grew up I was taught there were 9 planets in orbit around the sun, and the existence of (or at least abundance of) exoplanets where largely speculative, with the first observations just being confirmed during the 90's. When my kids grow up they'll be taught there are thousands of exoplanets in our very vicinity and millions in the galaxy. And there are free-floating bodies as well, rouge planets that are not gravitationally bound to a star! How cool isn't that? To top it all, we will soon have instruments sensitive enough to measure the very spectrum of an exoplanet atmosphere and look for biosignatures. If it finds free oxygen and methane, that's a very strong indication of life as we know it. (Since oxygen is highly reactive, it tends to show up in compounds such as carbon or silicon dioxide. Biologic activity is one possible supply of free oxygen.) The search for extra-terrestrial life, long belonging to the realm of science fiction, has turned to a serious and highly active field of research in just a few years.
There are actually a few ways that planets are detected. The dimming of the star as a planet passes in front of it is one method. This only works if the planet passes exactly between us and the star while we're looking. This can only happen is the planetary system is aligned the right way (more or less side-on) to us. It also tends to favour detecting larger planets with fast orbits (an alien looking at our solar system would have to wait one year to see the Earth pass the sun twice, and decades for some of the outer planets).
Another method is to detect the 'wobble' of the star as its planets orbit it. Even though stars are very big and their planets very small, the gravity of planets orbiting a star does pull the parent star around a little, and we can detect that. This tends to favour bigger planets that are orbiting close to the host star as well.
Another is to look for microlensing effects (as an object with a large mass, like a planet, passes in front of a star it can act like a lens, bending the light and causing a brightening effect on background stars). Again, this is biased towards larger planets.
To answer your question, though, in principle, if the planet that's passing in front of the star is very bright it would throw off calculations. However, for it to have enough an an effect to be noticeable it'd have to be very bright, because stars are VERY bright. A planet covered in street lights would still be essentially black when compared to the light emanating from its host star, and eve if it were covered with lava, the lava glow wouldn't make much of a difference, either.
In fact, if you think about it, a really bright planet would be even more detectable. The problem with seeing planets orbiting their stars is that their stars are so bright, the planets get lost in the glare of their star. If a planet was bright enough to throw off the calculations, it might be bright enough to be seen!