终极一班3

'NASA ready to take whatever Universe throws at us'_我的网站

一 |     Washington, Oct 12 (UNI) American space agency NASA says its recent attempt to deflect the path of an asteroid was successful, after its Dart probe struck an asteroid head-on.
Scientists have now confirmed the orbit of a 160m-wide space rock known as Dimorphos was altered when the Dart probe struck it head on last month.
Researchers came to the conclusion after making measurements using a range of space and Earth-based telescopes.
The mission was conceived to test a potential strategy to defend the Earth against threatening objects.
Dart's achievement proves such an idea would work, provided it was initiated early enough and the target wasn't overly massive.
"This mission shows that Nasa is trying to be ready for whatever the Universe throws at us," said agency administrator Bill Nelson.
"I believe that Nasa has proven that we are serious as a defender of the planet," he told reporters.
The space agency released a raft of data on Tuesday to support its assessment, including new pictures from the Hubble Space Telescope and from a small Italian spacecraft that stood off from the impact by about 50km (30 miles).
The Double Asteroid Redirection Test (Dart) took place some 11 million km (7 million miles) from Earth.
It saw the refrigerator-sized Nasa satellite drive straight into Dimorphos at 22,000km/h (14,000mph), destroying itself in the process.
The space rock orbits a much larger (780m wide; 2,550ft) object called Didymos. Before impact, the time taken for Dimorphos to make one circuit of its sibling was 11 hours and 55 minutes.
The telescope evidence now indicates this orbital period has been reduced to 11 hours and 23 minutes - a change of 32 minutes. This corresponds to Dimorphos moving closer into to Didymos by "tens of metres".
Nasa had defined a minimum successful period change of Dimorphos of 73 seconds or more. The results released on Tuesday show Dart surpassed this benchmark by more than 25 times.
"This is a 4 percent change in the orbital period of Dimorphos around Didymos. Dart just gave it a small nudge. But if you wanted to do this in the future, you'd want to do it years in advance," commented Nancy Chabot from the Johns Hopkins University Applied Physics Laboratory, which led the mission for Nasa.
"Warning time is really key here in order to enable this sort of asteroid deflection to be used in the future as part of a much larger planetary defence strategy."
Nasa's Dart programme scientist, Tom Statler, also had a word of caution about drawing too many conclusions from the experiment.
Asteroids came in many different guises, he said. Their compositions and constructions were diverse - something that was being emphasised every time a mission visited a new object.
"We should not be too eager to say one test on one asteroid tells us exactly how every other asteroid would behave in a similar situation," he stressed.
"But what we can do is use this test as an anchor point for our physics calculations in our simulations that tell us how different kinds of impacts in different situations should behave."
Four years from now, the European Space Agency (Esa) will have three spacecraft - collectively known as the Hera mission - at Didymos and Dimorphos to make follow-up studies.
UNI ING。    

    
    　　克利夫兰骑士队官方宣布，球队已正式签下佩顿-沃特森。这位年轻前锋将身披8号球衣，为新东家征战新赛季。

二 |
    
    　　沃特森此前通过一笔多方交易，以先签后换方式从丹佛掘金加盟骑士。据此前报道，其新合同为4年8800万美元，包含7.5%的交易保证金，最后一年为球员选项。
    
    　　上赛季，沃特森场均贡献14.9分、4.9个篮板、2.1次助攻和1.1次盖帽，三分命中率高达41%，展现了攻防两端的全面潜力。

三 |
    
    　　骑士篮球运营总裁奥尔特曼在声明中表示：“沃特森是一位年轻且有天赋的球员，我们相信他非常契合球队的发展方向。他的身高、运动能力和防守多面性使他能够胜任多个位置，并在攻防两端为我们创造更多灵活性。他在这个联盟中持续成长，我们相信他在克利夫兰有机会再上一个台阶。”
    
    　　奥尔特曼同时向离队球员表达了感谢：“我们要向斯特鲁斯致以感谢，感谢他为骑士队所做的一切。

四 | 在过去的几个赛季中，斯特鲁斯已成为我们球队、文化和身份认同的重要组成部分。他的职业精神、坚韧、竞争意识和领导力，帮助塑造了我们在这里建立的标准。他是我们持续崛起的重要一环，我们无比感激他的贡献。”
    
    　　关于施罗德，奥尔特曼表示：“施罗德在交易截止日加盟后立即产生了影响，为球队带来了经验、韧性和领导力。他的贡献帮助我们自2018年以来首次打入东部决赛，我们感谢他在骑士队期间付出的一切，祝愿他未来一切顺利。

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