For the first time, an Earth-sized planet has been found in the habitable zone of its star. This discovery not only proves the existence of worlds that might be similar to our own, but will undoubtedly shape future investigations of exoplanets that could have terrestrial surface environments.
The new-found body, orbiting the red dwarf star Kepler-186 and designated Kepler-186f, is the fifth — and outermost — world to be discovered in this system. The results are described in an article appearing in Science.
“This is the first definitive Earth-sized planet found in the habitable zone around another star,” says lead author Elisa Quintana of the SETI Institute at NASA Ames Research Center. “Finding such planets is a primary goal of the Kepler space telescope. The star is a main-sequence M-dwarf, a very common type. More than 70 percent of the hundreds of billions of stars in our galaxy are M-dwarfs.”
San Francisco State University astronomer Stephen Kane and an international team of researchers have announced the discovery of a new rocky planet that could potentially have liquid water on its surface.
The new planet, dubbed Kepler-186f, was discovered using NASA’s Kepler telescope, launched in March 2009 to search for habitable zone, Earth-sized planets in our corner of the Milky Way Galaxy. A habitable zone planet orbits its star at a distance where any water on the planet’s surface is likely to stay liquid. Since liquid water is critical to life on Earth, many astronomers believe the search for extraterrestrial life should focus on planets where liquid water occurs.
“Some people call these habitable planets, which of course we have no idea if they are,” said Kane, an assistant professor of physics and astronomy. “We simply know that they are in the habitable zone, and that is the best place to start looking for habitable planets.”
An international team of planetary scientists determined that the Moon formed nearly 100 million years after the start of the solar system, according to a paper to be published April 3 in Nature. This conclusion is based on measurements from the interior of the Earth combined with computer simulations of the protoplanetary disk from which the Earth and other terrestrial planets formed.
The team of researchers from France, Germany and the United States simulated the growth of the terrestrial planets (Mercury, Venus, Earth and Mars) from a disk of thousands of planetary building blocks orbiting the Sun. By analyzing the growth history of the Earth-like planets from 259 simulations, the scientists discovered a relationship between the time the Earth was impacted by a Mars-sized object to create the Moon and the amount of material added to the Earth after that impact.
New global imaging and topographic data from MESSENGER show that the innermost planet has contracted far more than previous estimates. The results are based on a global study of more than 5,900 geological landforms, such as curving cliff-like scarps and wrinkle ridges, that have resulted from the planet’s contraction as Mercury cooled. The findings, published online March 16, 2014, in Nature Geoscience, are key to understanding the planet’s thermal, tectonic, and volcanic history, and the structure of its unusually large metallic core.
Researchers have developed a new approach to simulating the energetic processes that may have led to the emergence of cell metabolism on Earth — a crucial biological function for all living organisms.
The research, which is published online today in the journal Astrobiology could help scientists to understand whether it is possible for life to have emerged in similar environments on other worlds.
Dr. Terry Kee from the School of Chemistry at the University of Leeds, one of the co-authors of the research paper, said: “What we are trying to do is to bridge the gap between the geological processes of the early Earth and the emergence of biological life on this planet.”
Previously, some scientists have proposed that living organisms may have been transported to Earth by meteorites. Yet there is more support for the theory that life emerged on Earth in places like hydrothermal vents on the ocean floor, forming from inanimate matter such as the chemical compounds found in gases and minerals.