Interstellar visitor Oumuamua may be a 900ft long hydrogen iceberg

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Interstellar visitor Oumuamua may be a 900ft long hydrogen iceberg – and scientists say there could be more on the way

  • Researchers looked at the properties shown by the 900ft Oumuamua visitor 
  • They found it was likely made of frozen hydrogen – something rare in nature 
  • This hydrogen iceberg could be the first of many coming into the solar system 

By Ryan Morrison For Mailonline

Published: | Updated:

The interstellar visitor named Oumumua may be made up entirely of hydrogen ice, something rarely seen in nature, according to scientists.

The ‘weird object’ was first discovered in 2017, sparking speculation over its origin and make-up, with theories ranging from a comet to a cigar shaped spaceship.

Yale astronomers developed a theory that aimed to explain the unusual properties shown by Oumuamua – they found it was effectively a ‘hydrogen iceberg’. 

The team say this solid form of hydrogen seen flying through space is a ‘new kind of object’ but there will be more showing up in the solar system in the future.

The ‘weird object’ was first discovered in 2017, sparking speculation over its origin and make-up with theories ranging from a comet to a cigar shaped spaceship

Oumumua has now passed beyond Saturn’s orbit but will take another 10,000 years before it leaves the solar system for its next interstellar destination.

Lead author Darryl Seligman, now at the University of Chicago, said the 900ft long object has several unusual properties including varying rapidly in brightness.

He said this suggested it was either saucer shaped or cigar shaped.

The team say it accelerated in a fashion similar to comet but showed no evidence of emitting gas or the billows of dust normally seen trailing a comet.

Seligman and co-author Gregory Laughlin say ‘Oumuamua’s behavior can be explained if it is composed of hydrogen ice.’ 

Hydrogen is the most common element in the universe but it is rarely found in solid form as this requires extremely cold temperatures.  

The team say the way frozen hydrogen reacts to sunlight could present a compelling mechanism for acceleration.  

‘As ‘Oumuamua passed close to the Sun and received its warmth, melting hydrogen would have rapidly boiled off the icy surface,” Laughlin said.

This resulted in ‘providing the observed acceleration and also winnowing ‘Oumuamua down to its weird, elongated shape – much as a bar of soap becomes a thin sliver after many uses in the shower.’

Oumumua has now passed beyond Saturn's orbit but will take another 10,000 years before it leaves the solar system for its next interstellar destination

Oumumua has now passed beyond Saturn’s orbit but will take another 10,000 years before it leaves the solar system for its next interstellar destination

The team say iceberg-like objects made of hydrogen could potentially form in the dense cores of molecular clouds that pervade the Milky Way galaxy.  

These dense clouds give rise to new stars and planetary systems. 

‘Their presence would be an accurate probe of the conditions in the dark recesses of star-forming clouds and provide a critical new clue for understanding the earliest phases of the still-mysterious processes that generate the birth of stars and their accompanying planets,” Laughlin said.

The authors say these hydrogen icebergs, and even hydrogen comets, could be more common in the solar system than researchers first thought.

They say that if they were formed in the dark recesses of molecular clouds it could give clues to the ways stars and planets are formed throughout the universe.

Claims of it being an alien probe, put forward because of its unusual shape and properties, were quickly rejected by astronomers. 

AN INTERSTELLAR VISITOR: WHAT IS ‘OUMUAMUA AND WHAT DO WE KNOW ABOUT IT?

A cigar-shaped asteroid named ‘Oumuamua sailed past Earth at 97,200mph (156,428km/h) in October.

It was first spotted by a telescope in Hawaii on 19 October, and was observed 34 separate times in the following week. 

It is named after the Hawaiian term for ‘scout’ or ‘messenger’ and passed the Earth at about 85 times the distance to the moon.

It was the first interstellar object seen in the solar system, and it baffled astronomers.

Initially, it was thought the object could be a comet. 

However, it displays none of the classic behaviour expected of comets, such as a dusty, water-ice particle tail.

The asteroid is up to one-quarter mile (400 meters) long and highly-elongated – perhaps 10 times as long as it is wide.

That aspect ratio is greater than that of any asteroid or asteroid observed in our solar system to date.

But the asteroid’s slightly red hue — specifically pale pink — and varying brightness are remarkably similar to objects in our own solar system.

Around the size of the Gherkin skyscraper in London, some astronomers were convinced it was piloted by aliens due to the vast distance the object traveled without being destroyed – and the closeness of its journey past the Earth. 

Alien hunters at SETI – the Search for Extra-terrestrial Intelligence based at Berkeley University, California said there was a possibility the rock was ‘an alien artefact’.

But scientists from Queen’s University Belfast took a good look at the object and said it appears to be an asteroid, or ‘planetesimal’ as originally thought. 

Researchers believe the cigar-shaped asteroid had a ‘violent past’, after looking at the light bouncing off its surface. 

They aren’t exactly sure when the violent collision took place, but they believe the lonely asteroid’s tumbling will continue for at least a billion years.