A.has been
B.were
C.was
D.have been
.阅读理解
A
(2015·江苏省四校第三次联考)Scientists have many theories about how new planets are born. But they have never seen one actually take shape — until now. Astronomers using the European Southern Observatorys Very Large Telescope believe they have spotted a baby planet forming in deep space. “If we are correct, this is the first time we are seeing a planet forming inside its natal environment,” says astronomer Sascha Quanz, leader of the team that made the discovery.
Scientists are excited because the images they have captured are a photographic first. But they may also have learned something new about how planets get started.
If this dust cloud is a new planet, it?s a big one. HD 100546b, as the new formation is called, could grow much larger than Jupiter, the biggest planet in our solar system.Scientists think HD 100546b is a gas giant. Gas giants are huge planets like Jupiter and Saturn that are made mostly from gases like hydrogen and helium (氦).
HD 100546b is located 335 light years from Earth. A light year is the distance light can travel in one year, or about 6 trillion miles. So the baby planet may seem far, but compared with many other distant stars and galaxies in our universe, it’s actually relatively close. Our galaxy, the Milky Way, is 100,000 light years wide.
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