'Cataclysmic' collision of giant asteroids is discovered by NASA's James Webb Space Telescope around a nearby star - and it only happened 20 years ago, scientists say

NASA's James Webb Space Telescope was built to 'see back in time', up to a whopping 13.5 billion years ago – but its latest discovery is surprisingly recent.

Just 20 years ago, a collision occurred between two asteroids orbiting Beta Pictoris, a star 63 light-years from Earth, the $10 billion observatory reveals. 

This 'cataclysmic' impact event pulverized the two rocky bodies into fine dust particles 'smaller than pollen or powdered sugar', astronomers say. 

Collectively, these dust particles were about 100,000 times the size of the asteroid that killed the dinosaurs around 66 million years ago. 

In our own solar system, asteroids collide with each other and even with planets, posing a threat to lifeforms – although as it stands there's no known worlds orbiting Beta Pictoris that could host aliens. 

Beta Pictoris – which is nearly twice as massive as our sun and more than eight times as luminous – has long been of interest for astronomers because it's relatively young.

Our sun is 4.5 billion years old, but Beta Pictoris is only 20 million years old – and this is a key age giant planets have formed but rocky planets may still be developing around it. 

Scientists have already confirmed the presence of two gas planets, Beta Pictoris b and Beta Pictoris c, orbiting it – but any rocky ones are yet to be discovered. 

'Beta Pictoris is at an age when planet formation in the terrestrial planet zone is still ongoing through giant asteroid collisions,' said Christine Chen, astronomer at Johns Hopkins University in Baltimore, Maryland.  

'So what we could be seeing here is basically how rocky planets and other bodies are forming.' 

It was 20 years ago that NASA's now-retired Spitzer Space Telescope observed a 'massive amount of dust' around Beta Pictoris. 

Along with Hubble, Compton and Chandra, Spitzer was one of NASA's four Great Observatories – large, powerful space telescopes launched between 1990 and 2003. 

At the time, it was thought that the dust around Beta Pictoris was from a constant stream created by two small rocky bodies grinding against each other. 

But after studying the same area 20 years later with the James Webb telescope, Chen and colleagues found the dust had gone. 

They think a massive collision between two asteroids created the ultra-fine dust grains, which gradually dispersed into space.

'We think all that dust is what we saw initially in the Spitzer data from 2004 and 2005,' said Chen. 

'With Webb's new data, the best explanation we have is that, in fact, we witnessed the aftermath of an infrequent, cataclysmic event between large asteroid-size bodies.' 

If rocky planets do exist in orbit around Beta Pictoris, they are yet to be found – or yet to form. 

But the findings suggest this faraway system may be going through a similar process of planetary formation that our solar system went though over 4 billion years ago. 

In young solar systems such as Beta Pictoris, 'early turmoil' can influence the atmospheres, water content and other key aspects of habitability that can eventually develop on their planets. 

The team also tip their hats to Spitzer, without which the dust from the collision would not have been detected.  

'Most discoveries by James Webb Space Telescope come from things the telescope has detected directly,' said co-author Cicero Lu, a former Johns Hopkins doctoral student in astrophysics.

'In this case, the story is a little different because our results come from what James Webb did not see.' 

The new insights are being presented on Monday at the 244th Meeting of the American Astronomical Society in Madison, Wisconsin.