Babe Among the Stars
Created | Updated Mar 19, 2009
Mortal as I am, I know that I am born for a day. But when I follow at my pleasure the serried multitude of the stars in their circular course, my feet no longer touch the earth - Ptolemy
Other Earth-like Planets
The Kepler Mission had a successful launch on 6 March, 2009. Named after the great German astronomer Johannes Kepler, the mission is designed to survey our region of the Milky Way galaxy to discover Earth-size planets in (or close to) the habitable zone of their own star, and determine how many of the billions of stars in our galaxy have such planets. You can download a widget for your desktop if you want to keep track of discoveries.
Since 1995 more than 340 planets, mostly gas giants like Jupiter, have been discovered orbiting other stars, of which over 220 are classed as 'nearby' (within 200 parsecs — 650 light years). Some are unsuitable for organic life due to other reasons, like their proximity to their own sun, for example: the orange dwarf star CoRoT-Exo-2 in the constellation Serpens has a gas giant planet CoRoT-Exo-2 b which completes an orbit in 42 hours.
Rocky worlds like the Earth have been detected, but they have been too close to their sun for the planet to support liquid water. Some planets have a distance much too extreme; they are so remote that if they were in our Solar System they'd orbit beyond its limits. Even if a rocky planet were discovered in the fabled 'Goldilocks Zone' — not too hot, not too cold — it would require a magnetic field to shield it from the parent star's radiation. And suitable gravity. And an atmosphere. These basics are just the start!
The closest rocky world to us — that we know of at the time of writing — is Gl 581 d, which orbits the red dwarf Gl 581 in the constellation Libra. This solar system is 20 light years away; a light year is the distance light travels in one year, roughly 5.88 trillion miles or 9.46 trillion km. That means it would take you 20 years to reach it, even if you could travel at the speed of light!
Intelligent Alien Life?
Alien life probably exists, and there's every possibility one of the species became sentient and rose to the top of the food chain through their intelligence. They may have evolved in much the same way human life did, and they might even have conquered the perils of venturing into space. Assuming they have a life-span similar to ours, would they set off on a hazardous trip to visit us, even if they knew of our existence? The thought of a representative of Gl 581 d exchanging flags on the White House lawn with Barack Obama exists only in the realms of science-fiction for now.
Thoughts on Alien Lifeforms
Here a variety of people voice their thoughts about alien life:
Earth's circumstances are really far too special to be easily replicated.
– Senior Adviser Dr Michael Perryman, European Space Agency
If alien life forms do exist, we may not necessarily be able to make contact with them, and we have no idea what form they would take.
–
Duncan Forgan of Edinburgh University
We think they're out there.
–
Seth Shostak of the Search for Extraterrestrial Intelligence (SETI) Institute
No question of belief. It's a fact that aliens have been visiting Earth for last several thousand years. Many of our technologies are gifts from them. It is a different matter that our Governments and some our scientists are in constant denial. Maybe this is their policy or perhaps the aliens have asked them to keep their identity secret in lieu of technical inputs given.
– Shailendra Singh, Mumbai
There will be most certainly be vast amounts of intelligent civilizations out there. The only problem is the vastness of space itself. Light itself takes hundreds of thousands of years to travel across our own galaxy and travel doesn't get any faster than that, as Einstein taught us. The idea that extra terrestrial life would be anything like us, like 95% of the extraterrestrials in science fiction books and films are bipeds, is far flung. They might just be 'intelligent shades of the colour blue' for all we can tell at this time. Or around an inch tall. Or experiencing time 50 times as slow as us. Communication could be quite a challenge. If we recognize them for what they are in the first place.
–
Dirk Jan, Rotterdam, Netherlands
What do you think?
Chat about your celestial observances at the H2G2 Astronomy Society. Comment on anything in this edition of Babe Among the Stars by starting a new conversation below.
