AP NEWS

Unveiling monster galaxies once hidden from view

May 6, 2017

When I look to the sky on a clear and moonless night, I am in awe of the beauty of the stars.

These stars were born from gas clouds within our galaxy home, the Milky Way, which is one of billions of galaxies in our universe. I observe distant galaxies and work to understand how they change over time.

Astronomy provides an amazing historical record.

Although the speed of light is very fast, distances in space are vast. Because light from a distant galaxy takes so long to reach us, we are seeing the way the galaxy looked in the past.

Just as we see our star, the sun, as it was eight minutes ago, we see these distant galaxies as they were billions of years ago.

My observations have revealed distant, giant galaxies that are forming new stars at a prodigious rate but cannot be seen in visible light, because they are cocooned in dust.

The dust – smoke-like particles, consisting of fine soot made of carbon or sandy silicates produced after the explosive deaths of massive stars – absorbs ultraviolet light emitted by hot young stars. It re-emits the starlight as heat radiation that can only be detected with radio telescopes located at very high altitudes, such at the ALMA Observatory in the Atacama Desert in Chile.

It is exhilarating to participate in the discovery of the most powerful galaxies in the universe, which were previously hidden from our view by dust, and to explore why these dusty monsters have nearly disappeared by the present day.