Thursday: Hubble and James Webb telescopes They released their first imagesThe intentional smashing of a spacecraft into an asteroidAs astronomers pointed out, the impact appears to have been greater than expected.
For a historic test of Earth’s ability to protect itself against an asteroid that could threaten its life, the telescopes around the world turned their attention towards Dimorphos this week.
Astronomers celebrated Monday night’s impact of NASA’s Double-Asteroid Redirection Testing (DART), which rammed into its rugby ball-shaped, pyramid-sized target at 11 million kilometers (6.8 millions miles) from Earth.
Images taken by Earth-bound telescopes showed a vast cloud of dust expanding out of Dimorphos – and its big brother Didymos which it orbits – after the spaceship hit.
These images showed matter spreading out over thousands upon kilometers. However, the James Webb images and Hubble images “zoomin much closer”, according to Alan Fitzsimmons (an astronomer at Queen’s University Belfast who was involved in observations for the ATLAS project).
James Webb or Hubble can provide a view of “within a few kilometers from the asteroids, and you can really see how the material flying out from that explosive DART impact,” Fitzsimmons said to AFP.
He said, “It’s really quite amazing.”
According to Hubble’s joint statement, James Webb’s Near-Infrared Camera was able to capture an image four hours after impact. It shows “plumes” of material as “wisps streaming away” from the centre of where the impact occurred.
Hubble images of the expanding spray from DART impact point show it in Hubble images taken at 22 minutes, five and eight hours respectively.
“Worried there was no more”
Ian Carnelli from the European Space Agency stated that the Webb images and Hubble images are “really amazing” and were similar to those taken by LICIACube, a satellite of toaster size. It was located just 50 km away from the asteroid following its separation from DART spacecraft.
Carnelli, who manages the ESA’s Hera Mission which intends inspect the damage in four year’s time, stated that the impact shown by the images is “a lot greater than we expected”.
Carnelli stated to AFP, “I was really afraid there was nothing left off Dimorphos.”
The Hera mission is set to launch in October 2024, and reach the asteroid in 2026. It had been expected to inspect a crater measuring 10 meters (33ft) in diameter.
It looks now like it will be much bigger, Carnelli stated, “if there are any craters at all, maybe one of Dimorphos has just been chunked off.”
DART’s true success will depend on how far it diverted the trajectory of the asteroid. This allows the world to prepare for bigger asteroids in the future.
Carnelli stated that it will take Earth-bound radars and telescopes about a week to get a first estimate of the extent of the asteroid’s orbital alteration, and three or four more weeks before a precise measurement is made.
‘Huge implications’
He said, “I am expecting an even bigger deflection than what we had planned.”
Carnelli explained that this would have “huge implications for planetary defence because it means that the technique can be used for larger asteroids”.
“We thought, until today, that the only way to deflect a nuclear device would be to send one.”
Fitzsimmons stated that even if no material was “flung off” Dimorphos’ orbit, DART would still have slight effects.
“But the greater the material’s velocity, the more deflection it will cause,” he stated.
The observations from James Webb and Hubble will help reveal how much – and how quickly – matter sprayed from the asteroid, as well as the nature of its surface.
The first time that the two space telescopes had observed the same celestial body was with the asteroid impact.
James Webb, who launched in December and released its first images in July has been named the most powerful Hubble space telescope.
Fitzsimmons stated that the images are a “beautiful demonstration of how science can be achieved by using more than one telescope simultaneously”.
