Study on Young Galaxy 'IZw 18' Shows Dust was Rare in Early Universe

Early universe might not be as dusty as previously believed, according to astronomers. The latest finding could mean that current theories on Universe formation need to be re-assessed.

The study team was led by Dr David Fisher, an astrophysicist at Swinburne University of Technology, and colleagues.

The latest study is based on the observation of dust in a young, dynamic galaxy called the IZw 18. The galaxy is quite near, about 59 million light years away. It is galaxies like these that provide astronomers with a sneak-peak into the early Universe.

"It's not just that the dust mass is low. We found that the dust mass is 100 times smaller than would be expected based on commonly assumed theories," Dr Fisher said.

Researchers found that the radiation in I Zw 18 is roughly 200 times stronger than the radiation found in our galaxy- the Milky Way. According to Fischer, the harsh environment inside the galaxy is affecting the amount of dust.

"IZw 18 is typical of very high redshift galaxies because it is very actively forming stars, and has a chemistry that is more like galaxies of the very early Universe with a very low abundance of metals and a lot of gas in the form of hydrogen," he said in a news release."Our result implies that current theories to describe the formation of stars when the Universe was very young are incomplete, and are built on invalid assumptions."

Astronomers said that theories on early Universe formation might require certain changes to account for the environment within the galaxy.

The study is published in the journal Nature.                                                                  

Previous research, by University of Texas researchers and colleagues, had suggested that large, dusty galaxies existed as far back as 13 billion years ago.