Hubble and Webb Images Reveal DART Impact Was Even Bigger Than Expected : ScienceAlert

Hubble and Webb Images Reveal DART Impact Was Even Bigger Than Expected : ScienceAlert
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The James Webb and Hubble telescopes on Thursday revealed his first images of a spaceship deliberately colliding with a asteroidas astronomers indicated that the impact appears to have been much larger than expected.

The world’s telescopes turned their gaze to the space rock Dimorphos earlier this week for a historic test of Earth’s ability to defend itself against a potentially deadly asteroid in the future.

Astronomers rejoiced when NASA’s Double Asteroid Redirection Test (DART) impactor slammed into its pyramid-sized, rugby-ball-shaped target 11 million kilometers (6.8 million miles). ) from Earth on Monday night.

Images taken by ground-based telescopes showed a large cloud of dust expanding from Dimorphos, and its orbiting older brother Didymos, after the spacecraft impacted.

While those images showed matter spread out over thousands of miles, the James Webb and Hubble images “come much closer,” said Alan Fitzsimmons, an astronomer at Queen’s University Belfast involved in observations with the ATLAS project.

An explosion of flickering blue light in space.
Combination of three of the images captured by NASA’s Hubble Space Telescope of the DART collision. (NASA, ESA, Jian-Yang Li (PSI); Alyssa Pagan (STScI))

James Webb and Hubble can offer a view “just a few kilometers from the asteroids and you can see the material from that explosive DART impact very clearly being blown away,” Fitzsimmons told AFP.

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

An image taken by James Webb’s Near Infrared Camera (NIRCam) four hours after the impact shows “plumes of material appearing as wisps moving away from the center where the impact took place,” according to a joint statement from the European Space Agency. , James Webb and Hubble.

Hubble images from 22 minutes, five hours, and eight hours after the impact show the spray of matter expanding from where DART struck.

‘Worried there would be nothing left’

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

The images show an impact that appears “much larger than we expected,” said Carnelli, director of ESA’s Hera mission, which intends to survey the damage in four years.

“I was really worried there wouldn’t be any Dimorphos left” at first, Carnelli told AFP.

The Hera mission, scheduled to launch in October 2024 and arrive at the asteroid in 2026, had hoped to survey a crater about 10 meters (33 feet) in diameter.

Now it looks like it will be much larger, Carnelli said, “if there is a crater, maybe a piece of Dimorphos has been cut off.”

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

It will likely take at least a week for ground-based telescopes and radar to get a first estimate of how much the asteroid’s orbit has been altered, and three to four weeks before there is an accurate measurement, Carnelli said.

‘Huge implications’

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

That would have “huge implications for planetary defense because it means this technique could be used for much larger asteroids,” Carnelli added.

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

Fitzsimmons said that even if no material had been “thrown” at Dimorphos, DART would still have slightly affected its orbit.

A flickering explosion tinted red in space.
A time lapse of the DART collision captured by Webb. (NASA, ESA, CSA, Cristina Thomas (University of Northern Arizona), Ian Wong (NASA-GSFC); Joseph DePasquale (STScI))

“But the more material and the faster it moves, the bigger the deflection,” he said.

Observations by James Webb and Hubble will help reveal how much matter, and how quickly, was ejected from the asteroid, as well as the nature of its surface.

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

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

Fitzsimmons called the images “a beautiful demonstration of the additional science that can be obtained by using more than one telescope simultaneously.”

© Agence France-Presse

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