1803 年 4 月，美国特使门罗与法国签订《路易斯安那购买条约》： 以1500万美元（约合今日 3.4 亿美元 ）购得从密西西比河到落基山脉的 82.8 万平方公里 土地。 一夜之间，美国的领土几乎翻倍，从“东部小国”变成横跨大陆的“潜在强国”。

NASA OSIRIS-REx sample collection event at Asteroid Bennu saw the spacecraft plunge its arm into the surface. Find out how ...

NASA's OSIRIS-APEX mission, which was one of 19 designated to be canceled by the Trump administration, has been saved from ...

At Edmonton Startup Week, Bennu’s Birdtender mixed cocktails and sparked a bigger conversation about how Canada turns ...

When the Bennu capsule returned to Earth scientists expected fragments of ancient rock What they found instead offered new clues about how planets form and how life may have begun in the early solar s ...

Ryugu’s samples reveal that water activity on asteroids lasted far longer than scientists thought, possibly reshaping ...

In April 2029, Apophis is predicted by NASA to come within 32,000 kilometers (20,000 miles) of the Earth's surface. Closer ...

From how space rocks wobble to where to hit them, scientists are learning the fine art of asteroid deflection — and it could ...

A NASA spacecraft touched down on the rugged surface of the Bennu asteroid on Tuesday, grabbing a sample of rocks dating back to the birth of our solar system to bring home.

A NASA probe orbiting an asteroid over 100 million miles from Earth will make a perilous attempt on Tuesday to snatch a sample from the celestial body’s rocky surface to bring home the space agency’s ...

According to a study conducted by University of Tokyo researchers, Ryugu maintained a "pristine record" of late water activity. By examining the lutetium and hafnium isotopes in their rock samples, ...

NASA has thrown a lifeline to scientists working on a mission to visit an asteroid that will make an unusually close flyby of ...