The James Webb and Hubble telescopes on Thursday revealed their first images of a spacecraft that deliberately crashed into an asteroid, marking the first time the two most powerful space telescopes have observed the same celestial object. The world’s telescopes turned their gaze on the Dimorphos space rock earlier this week for a historic test of Earth’s ability to defend itself against a potential future life-threatening asteroid.
Astronomers rejoiced when NASA’s Double Asteroid Redirection Test (DART) impactor struck its pyramid-sized target 11 million kilometers (6.8 million miles) from Earth on Monday night. Images taken by ground-based telescopes showed a huge cloud of dust expanding from Dimorphos – and its big brother Didymos, which it orbits – after the spacecraft hit.
While those images showed matter scattered thousands of kilometers away, the James Webb and Hubble images “get much closer,” said Alan Fitzsimmons, an astronomer at Queen’s University Belfast involved in the ATLAS observations. James Webb and Hubble can see “a few kilometers to asteroids, and you can really clearly see the material coming out of that explosive DART impact,” Fitzsimmons told . “It’s really spectacular,” he said.
Observations from space telescopes will help reveal how much and how fast matter is being spewed from the asteroid, as well as the nature of its surface. “Beautiful display” An image taken by James Webb’s Near-Infrared Camera (NIRCam) four hours after impact shows “clouds of material appearing as plumes streaming away from the center of the impact site,” according to a joint statement from the European Space Agency James Webb and Hubble.
James Webb’s images were shown in red because the telescope operates primarily in the infrared spectrum, allowing it to peer deeper into space than ever before. The images from the HST Wide Field Camera 3 were blue because they show the impact on visible light. Hubble images from 22 minutes, five hours and eight hours after impact show an expanding plume of matter from where DART hit the left side of the asteroid.
The real measure of DART’s success will be just how much it deflects the asteroid’s trajectory, so the world can begin to prepare to defend against larger asteroids that could be headed our way in the future. However, ground-based telescopes and radars will take days or even weeks to determine exactly where Dimorphos is relative to where it would be.
Measurements using the data will likely begin next week, Fitzsimmons said. “The problem we have at the moment is that there’s still a lot of dust and debris around the asteroids,” he said. “How quickly astronomers can make this measurement will depend on how accurately DART has been effective,” he added. The more the asteroid was off course, the easier the measurement would be.
Since launching in December and releasing the first images in July, James Webb has taken over from Hubble the title of the most powerful space telescope. With astronomers lined up for precious time to peer into space, the DART test is the first time both telescopes have observed the same event. Fitzsimmons said the images are “a beautiful demonstration of the extra science you can get from using more than one telescope at the same time.”
