Light from galaxies over 10 billion light-years away is helping an international team of scientists create a 3D map of what the Universe was like when it was just a teenager, at around 3 billion years old.
This new map outlines the Universe's "cosmic web," those filaments of dark matter that connect galaxies and everything else within the Universe. This web also contains hydrogen gas left over from the Big Bang.
Scientists created a new technique to do this, which allowed them to see the cosmic web nearly 11 billion light years away, when the Universe was younger. Using the light from distant galaxies to act as background light for hydrogen gas, they were able to create a map at a higher resolution than ever before.
Although this technique was once thought impossible, at least with modern telescopes, this team found out otherwise.
"I was surprised to find that existing large telescopes should already be able to collect sufficient light from these faint galaxies to map the foreground absorption, albeit at a lower resolution than would be feasible with future telescopes," says Khee-Gan Lee, a post-doc at the Max Planck Institute for Astronomy. "Still, this would provide an unprecedented view of the cosmic web which has never been mapped at such vast distances."
Scientists created the first 3D map of the Universe in 1998, but that data only allowed us to see to within about 1 billion light-years. New telescope technology, though, now allows us to map the Universe out much farther.
Using just four hours of observation time on the Keck I telescope in Hawaii, one of the largest telescopes in the world, astronomers collected their data. However, the distant galaxies' light was faint, which meant mapping the Universe at such a young age required a little help from scientists. The team created algorithms that subtracted other light from the sky that got in the way. Once those algorithms were in place, though, a laptop computer created the 3D map within a minute.
The map shows the cosmic web of the Universe at an unprecedented distance, allowing us to look back on the Universe's history when it was still young and undergoing a major "growth spurt."
Researchers hope to expand on this project, planning future telescope time to add in even more details.
"This technique is pretty efficient and it wouldn't take a long time to obtain enough data to cover volumes hundreds of millions of light years on a side," says Lee.
