The planet, called TOI 700 d, was discovered by NASA's TESS , and is one of only a few Earth-sized planets discovered in a star's habitable zone.

Paul Hertz, astrophysics division director at NASA Headquarters in Washington, D.C.,said，“TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars. Planets around nearby stars are easiest to follow up with larger telescopes in space and on Earth.”

“Discovering TOI 700 d is a key science finding for TESS.” The planet orbits a small,cool star called TOI 700, which is located just over 100 light years away from Earth. The star is roughly 40% of the Sun's mass and size, and about half its surface temperature.

Several planets appear to orbit the star.The innermost planet, TOI 700 b, is a rocky planet that's almost exactly the same size as Earth, while the middle planet, TOI 700 c, is 2.6 times larger than Earth, and is a gasdominated world.

Finally, the outermost planet, TOI 700 d,is the only one in the habitable zone, and is around 20% larger than Earth.

To confirm the planets' sizes and compositions, NASA used its Spitzer Space Telescope.

While TOI 700 d's exact conditions are un-known, the researchers used 3D climate models to predict its surface type and atmospheric composition.

One model suggests that the planet may be ocean-covered with a dense, carbon-dioxidedominated atmosphere, while an other indicates that TOI 700 d could be an all-land version of modern Earth.

The researchers hope that further data on the planet will help to work out which of these models is correct.

Gabrielle Engelmann-Suissa, a universitiy space research association visiting research assistant at Goddard, added，“Someday, when we have real spectra （光譜） from TOI 700 d, we can backtrack, match them to the closest simulated spectrum, and then match that to a model.It's exciting because no matter what we find out about the planet, it's going to look completely different from what we have here on Earth.”

閱讀檢測

1. What's the main task of TESS?

A. To look for civilization from outer space.

B. To find Earth-sized planets in space.

C. To guarantee the Earth is in a safe state.

D. To provide scientists with more models.

2. What is TOI 700 b mainly made of?

A. Rocks.

B. Gas.

C. Soils.

D. Water.

3. How did Gabrielle Engelmann-Suissa feel about the possible findings of TOI 700 d?

A. Worried.

B. Proud.

C. Excited.

D. Upset.

語言學習

難句分析

While TOI 700 d's exact conditions are unknown, the researchers used 3D climate models to predict its surface type and atmospheric composition. 雖然TOI 700 d的確切情況尚不清楚,但研究人員使用3D氣候模型來預測它的表面類型和大氣成分。

【點石成金】本句是一個主從復合句。 While引導讓步狀語從句,主句的主語是the researchers,主句中的to predict its surface type and atmospheric composition為不定式短語作目的狀語。