Through a glass darkly

The Hubble Space Telescope captured some of the oldest light in the universe. Webb will go farther. But what will the telescopes of the future be capable of? The Hubble Ultra Deep Field/NASA

Through a glass darkly

To see “through a glass” — a mirror — “darkly” is to have an obscure or imperfect vision of reality. The expression comes from the writings of the Apostle Paul; he explains that we do not now see clearly, but at the end of time, we will do so.

When reading this ancient definition of reality conjured up over 2000 years by the Apostle Paul, the notion of looking back in time via telescopes like the Hubble come to mind as man has forever questioned the nature of reality since the beginning of time. 

The James Webb Space Telescope can see back to the first stars and galaxies, but it will be blind to the cosmic dark ages and the Big Bang. STSci/NASA

Let’s start with something very obvious. When we look up at the night sky, we can see the stars because the universe is see-through. Light can travel hundreds of millions of years — billions, even — across the transparent void to reach us. Lucky for us, scientists can use this light to study the history of the cosmos, and our place in it.

But there was a time when our universe was not transparent but opaque. In the beginning, there was darkness.

Darkness Darkness - The Youngbloods

There are a few concepts for putting a telescope on the far side of the moon. One is actually called Farside. This one is is the Lunar Crater Radio Telescope, which would nestle the observatory in a moon crater. Saptarshi Bandyopadhyay/NASA Jet Propulsion Laboratory

How do you see a region of space from which no light emanates? Scientists, surprisingly, have some solutions to this problem.

One is to build a radio telescope on the far side of the moon (that is, the side that never faces the Earth). This type of telescope could help scientists peer into the dark ages, though not necessarily all the way back to the Big Bang.

During the dark ages, astronomers believe, the hydrogen that pervaded the universe emitted very faint radio waves. And that gives astronomers some hope. “You could look back into the dark ages, because those atoms were giving off radio waves,” Hertz says.

It’s as though they were broadcasting a lonesome signal from near the beginning of time, which could make it through the fog.

“If you build the right kind of radio telescope, very large, very sensitive, then you would be able to detect the radio waves and we could study the universe before the first stars and first galaxies,” Hertz says.

But we can’t detect these faint radio waves from Earth. All the radio transmissions that are produced on Earth would drown them out.

This is where the moon comes in — as a kind of giant shield. The moon is “thousands of miles of rock, so the radio waves can’t get through that,” Hertz explains. The far side of the moon is quiet enough for us to listen in.

But seeing even further requires seeing gravity @ large scale

An illustration of how two black holes colliding creates gravitational waves. VIA LIGO

Currently, NASA and the European Space Agency have plans for a space-based gravitational observatory called LISA (the Laser Interferometer Space Antenna), to launch in 2034. It will be a constellation of three satellites that form a triangle, with each side measuring a whopping 2.5 million kilometers.

“It measures whether the distance between the satellites has changed,” Hertz explains. “And if it changes, it’s because a gravitational wave went by and shrank or expanded space.”

Some of those gravitational waves could be coming from that hot cauldron of the post-Big Bang universe.

I can see clearly now.