Hubble and Webb images reveal Dart’s impact was bigger than expected: Science alert

Hubble and Webb images reveal Dart's impact was bigger than expected: Science alert
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James Webb and the Hubble Telescope on Thursday Their first photo release Deliberately smashing into a spacecraft the asteroidAs astronomers have indicated the effect appears to have been much greater than expected.

Telescopes around the world turned their attention to the space rock Dimorphos earlier this week for a historic test of Earth’s ability to defend itself against a potentially life-threatening asteroid in the future.

Astronomers rejoiced Monday night as NASA’s Double Asteroid Redirection Test (DART) impactor hit a pyramid-shaped, rugby ball-shaped target 11 million kilometers (6.8 million miles) from Earth.

Images taken by Earth-bound telescopes show a huge cloud of dust after the spacecraft hit Dimorphos – and its older brother Didymos, which it orbits.

While these images show material sprayed over thousands of kilometers, the James Webb and Hubble images “zoom in much closer,” said Alan Fitzsimmons, an astronomer at Queen’s University Belfast involved in observations with the ATLAS project.

An explosion of brilliant blue light in space.
Three images from NASA’s Hubble Space Telescope collectively captured the DART collision. (NASA, ESA, Jian-Yang Lee (PSI); Alyssa Pagan (STScI))

James Webb and Hubble can provide a view “within just a few kilometers of the asteroid and you can see really clearly how the material is being blown off by that explosive impact of the dart,” Fitzsimmons told AFP.

“It’s really quite spectacular,” he said.

An image taken four hours after the impact by James Webb’s near-infrared camera (NIRCAM) shows “plumes of material drifting away from the center of the impact,” according to a joint statement by the European Space Agency. Webb and Hubble.

Hubble images at 22 minutes, five hours and eight hours of impact show a spray of material extending from where the DART hit.

‘There was nothing left to worry about’

The European Space Agency’s Ian Carnelly said the “really impressive” Webb and Hubble images were remarkably similar to those taken by the toaster-sized satellite LICIACube, which was just 50 kilometers from the asteroid after it separated from the DART spacecraft a few weeks ago. .

The images depict an impact that looks “much bigger than we expected,” said Cornelli, manager of ESA’s Hera mission, which plans to inspect the damage in four years.

“At first I was really worried that there was nothing left of Dimorphos,” Carnelly told AFP.

The Hera mission, which will launch in October 2024 and reach the asteroid in 2026, hoped to survey a crater 10 meters (33 feet) in diameter.

Now it looks like it would be much bigger, Carnelly said, “if there’s a hole there, maybe a piece of dimorphos was torn off.”

The true measure of DART’s success will be how much it deflects the asteroid’s trajectory, so the world can begin preparing to defend itself against larger asteroids headed our way in the future.

Carnelly said it will likely take Earth-bound telescopes and radars at least a week to get a first estimate of how much the asteroid’s orbit has changed, and three or four weeks before a definitive measurement can be made.

‘huge effect’

“I expect a much bigger deviation than we planned,” he said.

This will have “huge implications for planetary defense because it means that this technique can be used for much larger asteroids”, Carnelli added.

“Until today, we thought that the only diversion strategy would be to send a nuclear device.”

Fitzsimmons said that even if no material was “flowing” Dimorphos, the dart would still affect its orbit somewhat.

A bright red explosion in space.
A timelapse of the DART collision captured by Webb. (NASA, ESA, CSA, Christina Thomas (Northern Arizona University), Yan Wong (NASA-GSFC); Joseph DePasquale (STScI))

“But the more material and the faster it’s moving, the more deviation there will be,” he said.

James Webb and Hubble’s observations will help reveal how much — and how fast — material has been sprayed from the asteroid, as well as the nature of its surface.

The asteroid impact marked the first time that two space telescopes observed the same celestial object.

Since launching in December and releasing its first images in July, James Webb has taken the title of Hubble’s most powerful space telescope.

Fitzsimmons said the images are “a beautiful demonstration of the additional science you can get using multiple telescopes at once.”

© Agence France-Presse

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