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Earthlike Planet Orbiting Nearby Star
The Bad Astronomer writes "Astronomers in Europe have announced the discovery of a planet with only 5 times the Earth's mass, orbiting a red dwarf star 20 light years away. It orbits the star so closely that it only takes 13 days to go around... but the star is so cool that the temperature of the planet is between 0 and 40 Celsius. At this temperature there could be liquid water. Models indicate the planet is either rocky like the Earth or covered in an ocean. While it's not known if there actually is liquid water on the planet, this is a really big discovery, and indicates that we are getting ever closer to finding another Earth orbiting an alien star."
The BBC and Scientific American have good quotes from Stephane Udry of the Geneva Observatory, lead author of the scientific paper reporting the results. Others are already calling it "possibly habitable".
Very cool news!
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You forgot to account for the fact that the radius is 1.5 times that of Earth. The best estimate puts that planet at around 2.25 times earth gravity.
The link in the blog seems to be broken. There is some more information about the planet (Gliese 581 c) on Wikipedia, MSN, and Space.com.
Ronald said nothing. He flung himself from the room, flung himself upon his horse, and rode madly off in all directions.
Assuming its the same density as Earth, cube root of 5 is 1.7, so 1.7x the radius. Gravity is mass/r^2, 5/1.7^2 x earth, so 1.7 or 70% more. ie surface gravity only goes up with the cube root of mass, for a constant density, so 5x isn't as bad as it sounds. But if it has more rock, and less iron core, the surface might me much nicer.
as i said.. sent 10 years from now.. 20 light years at an average of 0.4 times the speed of light.. 2058 would be the arrival time.. then it communicates back data by laser.. 2078 would be the time we see the signals. of course this would require an international effort to prevent losing track of this project should a certain bloated government disappear *cough*.
still, this is within the realm of practicality, and if it returns promising results it could usher in a new era of colonization.
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Actually, this is not the smallest planet yet found. The first extrasolar planets are still the smallest known: the planets around the millisecond pulsar B1257+12: http://en.wikipedia.org/wiki/PSR_B1257+12
The optical planet hunters often conveniently forgot this system (or dismiss it for various reasons).
The problem isn't acceleration G forces. It's energy density. Even a "beamed core" antimatter annihilation system, to go 0.4 c with 100 mT of payload, would require about a thousand mT of antimatter. 10:1 antimatter/payload ratio. That's not even slightly realistic, even in the long term, and we're talking about only 0.4c.
About the most we could realistically hope for is somewhere between 0.01c to 0.1c. Antimatter-induced microfusion, dusty fission fragment rockets, thermal rockets, nuclear saltwater rockets, various kinds of sails, etc, seem to be the most realistic options. But probably not during our lifetimes.
Present day. Present time.
From Pubmed:
ORL J Otorhinolaryngol Relat Spec. 1995 Jul-Aug;57(4):189-93.
Effect of prolonged hypergravity on the vestibular system: a behavioural study.Sondag HN, de Jong HA, Oosterveld WJ.
Vestibular Department ENT, University of Amsterdam, The Netherlands.
Golden hamsters were exposed to conditions of 2.5 times normal gravity (hypergravity, HG) for 4 months. During this period, tests were carried out to study equilibrium maintenance, swimming behaviour and open-field behaviour of these HG hamsters and of control hamsters living in a normal-gravity environment. The tests proved to be useful devices for detecting differences in perceptive-motor behaviour between HG hamsters and control hamsters. The HG hamsters had more difficulties in balancing on tubes and orientation during swimming. In the open-field study, the HG hamsters showed less locomotor activity than control hamsters. However, no differences were observed between the groups in washing, rearing and number of times having defaecation. These findings indicate that the daily transition from 2.5 to 1 g was not experienced as stressful by the hamsters, although performance on several perceptive-motor tasks was decreased, especially during the first weeks.
When the policeman of the tie, rule you violate, hello punishment of the kitty?
Arthur C Clark addressed this issue in Songs of Distant Earth, actually. I was impressed. His solution? Put a big chunk of ice in front of the spacecraft and let it ablate away as the craft encounters bits of space debris; in fact, the plot involves the need to obtain another ice shield.