'I want to find another Earth. That's what I'm living for.'
MIT astrophysicist Sara Seager has been looking at planets beyond our solar system, known as exoplanets, for almost 20 years.
When the first ones were discovered in the 1990s, many questioned the finding and didn't think it was real. But since then, with better technology, we have observed more than 6,000 of them, most of which are giant balls of gas.
西格對于如何探索充滿自信。
Dwarfing even Jupiter-HD-106906b is a gaseous planet 11 times more massive than Jupiter. The planet is believed to have formed in the center of its solar system, before being sent flying out to the edges of the region by a violent gravitational event.
Scorched world- Kepler-10b orbits at a distance more than 20 times closer to its star than Mercury is to our own sun. Daytime temperatures exceed 1,300 degrees Celsius (2,500 degrees Fahrenheit), which is hotter than lava flows on Earth.
Real-life Tatooine- This Jupiter-like planet in the HD-188753 system 149 light-years from Earth has three suns. The main star is similar in mass to our own Sun. The system has been compared to Luke Sky walker's home planet Tatooine in 'Star Wars.'
Longest year in the universe- Kepler-421b is a Uranus-sized transiting exoplanet with the longest known year, as it circles its star once every 704 days. The planet orbits an oranger, K-type star that is cooler and dimmer than our Sun and is located about 1,000 light-years from Earth in the constellation Lyra.
Crowed nerghborhood - Astronomers discovered two planets less than three times the size of Earth orbiting sun-like stars in a crowded stellar cluster approximately 3,000 lght-years from Earth in the constellation Cygnus.
Red dwarfed - This artist's conception shows a hypothetical planet with two moons orbiting in the habitable zone of a red dwarf star. The majority of the sun's closet stellar neighbors are red dwarfs.
First second-Earth - Kepler-186f was the first validated Earth-sized planet to be found orbiting a distant star in the habitable zone. This zone a range of distance from a star where liquid water might pool on the planet's surface.
Super Venus-Kepler-69c is a super-Earth-size planet similar to Venus. The planet is found in the Habitable zone of a star like our sun, located approximately 2,700 light years from Earth in the constellation Cygnus.
Tiny worlds- The kepler-444 system formed when the Milky Way was just two billion years old. The tightly packed system is home to five planets that range in size, the smallest is comparable to the size of Mercury and the largest to Venus, orbiting their sun in less than 10 days.
Our older cousin- This artistic concept image compares Earth (left) to Kepler-452b, which is about 60 percent larger. Both planets orbit a G2-type star of about the same temperature; however, the star hosting Kepler-452b is6 billion years old--15 billion years older than our sun.
天空新“眼”
The majority of exoplanet discoveries have been made by the Kepler space telescope, after which most of them have been named. Launched in 2009, the telescope has now entered emergency mode 75 million miles away from Earth, due to a malfunction.
To study the atmospheres of potential Earth twins, scientists need new eyes in the sky.
To date, Seager has only been able to study the atmospheres of a handful of exoplanets -- all gas giants -- but she's involved in a new NASA program launching in 2017 to just scout the brightest nearby stars for small rocky planets in the habitable zone.
Called TESS (Transiting Exoplanet Survey Satellite), the two-year mission will accumulate data that will then be fed into the James Webb Space Telescope, the next Hubble, which is due to launch in 2018: 'It's going to be amazing,' says Seager.
The James Webb telescope -- named after the head of NASA during the pioneering era of the 1960s -- will look at the cosmos with unprecedented clarity thanks to its use of a primary mirror about five times larger than Hubble's. It will also offer direct imaging of exoplanets by blocking the blinding light of their host stars with special instruments that make them more visible. This will allow Seager and other astronomers to study exoplanets like never before.
Seager believes many of the planets in their search will be the rocky, watery worlds she's been looking for.
'I'm absolutely confident they're out there.'
“我堅信他們就在那里等著我們去發現。
gravitational
vt. 證實，驗證；確認；使生效
同學們下期見~拜拜~
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