Artist's impression of Earth-like planet Gliese 581g orbiting red dwarf star Gliese 581.
Credit: ESO
WASHINGTON: U.S. astronomers said they have discovered an Earth-sized planet that they think might be habitable, orbiting a nearby star, and believe there could be many more planets like it in space.
The planet, found by astronomers at the University of California, Santa Cruz, and the Carnegie Institution of Washington, is orbiting in the middle of the ‘habitable zone’ of the red dwarf star Gliese 581, which means it could have water on its surface.
Liquid water and an atmosphere are necessary for a planet to possibly sustain life, even if it might not be a great place to live, the scientists said.
The rocky planet has gravity
The scientists determined that the planet, which they have called Gliese 581g, has a mass three to four times that of Earth and an orbital period of just under 37 days.
Its mass indicates that it is probably a rocky planet and has enough gravity to hold on to an atmosphere, according to Steven Vogt, professor of astronomy and astrophysics at the University of California, Santa Cruz, and one of the leaders of the team that discovered the planet.
If Gliese 581g has a rocky composition similar to Earth's, its diameter would be about 1.2 to 1.4 times that of the Earth, the researchers said.
Planet considered rather close
The surface gravity would be about the same or slightly higher than Earth's, so that a person could easily walk upright on the planet, Vogt said.
Gliese 581g was discovered by scientists working on the Lick-Carnegie Exoplanet Survey, during 11 years of observing the red dwarf star Gliese 581, which is only 20 light years from Earth.
For astronomers, eleven years of observation is considered a short time and 20 light years, which is roughly 117.5 trillion miles, rather close. The Sun is around eight and a half light minutes from Earth.
Habitable zone dubbed the ‘terminator’
"The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common," said Vogt.
The planet is tidally locked to its star, meaning that one side is always facing the star and basking in perpetual daylight, and the other is in perpetual darkness because it faces away from the star.
I need a space ship
This is wonderful, makes me just want to hop onto a space ship and take a look.
twenty light years...well in
twenty light years...well in astronomical terms this maybe be "near" but given present earth technology 117 trillion miles,(l note you are using miles not Km !!)any encounter in any form is not going to happened...sadly.
gliese 581`
I would like to stimulate some discussion, and hopefully glean some worthwhile information with the following speculation about Gliese 581, the newly discovered planet that is tidally locked to its star - always showing the same face towards it.
Let's assume that life, like that on earth, could possibly exist in the temperate "comfort zone" ,
One day a comet, smaller rogue planet or large asteroid stikes Gliese 581 a massive but glancing blow - enough to start it spinning. Let's assume that this huge collision and the subsequent spin causes widespread disaster on the planet but some life forms survive and over the next several million/ billion years evolve as the planet stabilises. The entire planet would now be exposed to sunlight on a regular day/night basis. Perhaps the survivors were semi-sentient and the disaster was so traumatic that it became a deeply embedded racial memory, gradually becoming myth or legend as time went by.
Jump about 20 light years from Gliese to Earth and think about certain myths and legends among the Australian Aborigines, africans and the ancient Summerians.
The Aborigines' legend is that Australia was originally a twilight to dark land all the time which is why so many animals are nocturnal. The say it was like this until a dreamtime hero
came to the land with a burning torch which he placed in the sky to allow night and day to begin its cycle.
In Africa there is a legend that there was no night, only day and that the original people lived in great discomfort becase of the continuous heat, and could not sleep properly.Unable to bear these conditions any longer, the people prayed to God for relief from the heat. God heard their prayers and from that time onwards day followed night.
Of most interest is a Summerian story. This one stated quite clearly that it was always light and pleasant until "that awful thing broke through the sky. After that night followed day."
One would think that a tidally locked planet taking a big hit would fall out of orbit or be destroyed, but there is always the chance it would survive and the resultant spin would restabilise things.Wouldn't it slow down? The earth is slowing fractionally every year -is there a connection?
While not asserting anything, I thought the consideration of these myths and postulations might interest readers sufficiently to consider what possibilities there may be, and comment in future postings.
Regards,
Elmohu, Brisbnane
The Red Dwarf Star????
I hope to bring up some good discussion about the Red Dwarf star. It is my understanding, that stars become Dwarf at the end of there lives... If this is true then, I would assume that at some time in the past. The star was a giant and then the the planet would have been cooked. Or am I mistaken?
Assuming I am correct would this mean that there is little chance that the planet is or was ever habitable, since it was baked....
Dave Jancan
Plano Texas
exoplanets that may support life
As more and more exoplanets are discovered has anyone any serious idea what life may look like if discovered maybe it could be completely different to life on earth
Slightly misleading claims.
Namely the gravity on the planet would not be "the same or slightly" higher than on Earth, not as long as the planet has a mass a few times greater than Earth and similar composition (i.e. density). The gravity would also be a few times greater than on Earth and the average person would weigh a few hundred kilograms (double that for pounds!).
Not sure what like forms could evolve under such heavy gravity, but probably bacteria, plants and perhaps water life.