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A | 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。 Prosecutors said Tuesday they believe Alec Baldwin has "criminal culpability" in the deadly shooting of cinematographer Halyna Hutchins on the New Mexico set of "Rust."The special prosecutors investigating the "Rust" shooting said they intend to present the case to a grand jury within the next two months to "determine whether probable cause exists to bind Baldwin over on criminal charges."The actor was practicing a cross-draw on the Santa Fe set in October 2021 when the gun fired, striking the cinematographer and director Joel Souza, who suffered a non-life-threatening injury."After extensive investigation over the past several months, additional facts have come to light that we believe show Mr. Baldwin has criminal culpability in the death of Halyna Hutchins and the shooting of Joel Souza," special prosecutors Kari Morrissey and Jason Lewis said in a statement. "We believe the appropriate course of action is to permit a panel of New Mexico citizens to determine from here whether Mr. Baldwin should be held over for criminal trial."Baldwin's attorneys said they will "answer any charges in court.""It is unfortunate that a terrible tragedy has been turned into this misguided prosecution," his attorneys, Luke Nikas and Alex Spiro of Quinn Emanuel, said in a statement to ABC News.Baldwin was initially charged with two counts of involuntary manslaughter over the death of Hutchins. Special prosecutors in the case dropped those against the actor in April, though noted at the time that their investigation remains "active and ongoing" and that charges may be refiled."Rust" armorer Hannah Gutierrez was also charged with two counts of involuntary manslaughter. She also faces an additional charge of tampering with evidence, with state prosecutors claiming she handed off a small bag of cocaine following her interview with police the day of the shooting.Gun enhancement charges filed in the case against both Baldwin and Gutierrez were dropped in late February.Gutierrez's attorneys sought to have her charges dismissed, arguing there were jurisdictional and structural issues with the case tied to a change in prosecutors and alleged prejudicial statements made to the media.State District Court Judge Mary Marlowe Sommer denied the motion in August, saying any jurisdictional issues were cured after prosecutors filed an amended criminal information. The judge also said the defense failed to demonstrate "actual and substantial prejudice" to warrant such an "exceptional" remedy as dismissing the charges, and that extrajudicial statements are not something "that need to be addressed at this point."Earlier this month, Sommer ordered "Rust" producers to turn over documents to prosecutors on the agreement between Baldwin and Rust Productions. The production company was seeking to quash the special prosecutor's request.During the hearing, Morrissey said the production company "refused" a request by Gutierrez for more time to train Baldwin on the weapon. Morrissey argued the request was denied to keep production costs low, and that Baldwin, as a producer on the film, would benefit from lower costs."This entire tragedy occurred because Rust Productions cut corners every chance they could and they hired inexperienced and ill equipped crew members. So we have a situation where Rust Productions is doing everything it can to keep costs low so that it can keep profits high," Morrissey said during the Oct. 6 hearing.David Halls, the first assistant director for the film, was sentenced in March to six months unsupervised probation as part of a plea deal. Halls, who handed the Colt .45 revolver to Baldwin prior to the shooting, was charged with negligent use of a deadly weapon.。
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