"We keep pushing the limits of what we can detect, and we're getting closer and closer to finding Earths," team member Steven Vogt said in a statement. Vogt is a professor of astronomy and astrophysics at the University of California, Santa Cruz.
The search for other "Earths" is often tied to the quest for life on other planets. Scientists theorize that many Earthlike planets may exist in orbits around distant stars. (See "Many "Earths" Are Out There, Study Says.")
Some planets could even orbit in a so-called Goldilocks Zone (not too hot, not too cold). There, a planet's surface temperature could be just right to sustain liquid waterand possibly life as we know it.
Such life is extremely unlikely on the new "super Earth," however. The planet orbits so close to Gliese 876 that its surface temperatures are estimated at 400 to 750 degrees Fahrenheit (200 to 400 degrees Celsius).
Direct observation of the new world is not yet possible, leading scientists to speculate about its composition.
"The planet's mass could easily hold onto an atmosphere," said Gregory Laughlin of the Lick Observatory at the University of California, Santa Cruz, in a media release. "It would still be considered a rocky planet, probably with an iron core and a silicon mantle. It could even have a dense steamy water layer.
"I think what we are seeing here is something that's intermediate between a true terrestrial planet like the Earth and a hot version of the ice giants Uranus and Neptune," Laughlin added.
The newfound planet was identified at the W.M. Keck Observatory on Hawaii's Mauna Kea volcano. Scientists announced the discovery Monday at the National Science Foundation in Arlington, Virginia.
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