Odds Favor Discovery of Earth-Like Exoplanet in 2013 90
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.
Comment removed (Score:5, Insightful)
Re:Poor definitions (Score:5, Insightful)
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.
Re:Earth-like lights (Score:3, Insightful)
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!