While others train their telescopes on stars and galaxies, astronomer Carlos Vargas can’t stop searching for the stuff in between.
The University of Arizona researcher studies the invisible “oceans of gas” that surround galaxies and make up one of the universe’s largest and least understood reservoirs of matter.
Now with the help of a $20 million grant from NASA, Vargas and his team plan to build and launch a small space telescope to observe these low-density gas clouds, which have fascinated and frustrated astrophysicists for decades.
The mission is called Aspera, and it will use a special ultraviolet sensor to scan the “gaseous halos” of 10 sample galaxies across a distance of up to 50 million light-years.
The orbital telescope will see in what Vargas called the “extreme UV,” picking up light that’s invisible to the naked eye with frequencies approaching that of X-rays.
Earth’s ozone layer blocks such UV rays, he said, “so you have to go into space” to see the gas clouds that ebb and flow through the intergalactic medium, supplying fuel for the birth of stars.
“We’re looking at the stuff outside the stuff most astronomers look at,” said Vargas, the principal investigator in charge of the mission.
The goal of Aspera is to determine “how much of this stuff actually exists” and what it can tell us about how galaxies evolve over time, Vargas said.