NASA’s John Mather on the Expanding Universe

You’ve said the James Webb Space Telescope “is so sensitive that it can measure the heat of a bumblebee at the distance of the moon.” Bumblebees probably aren’t the main thing you’re looking for in space. What capabilities of Webb are most exciting to you? Do you have a favorite image the telescope has produced?

JWST can look farther out in space and farther back in time to see how the first stars, black holes, and galaxies grew from the primordial material of the expanding universe. For me the most exciting picture is the one released by President Biden on July 11, 2022, showing dozens of highly magnified images of the most distant galaxies we’ve ever studied in detail. It also shows some of the most distant galaxies we’ve detected, even though they look like fuzzy dots. We’ve already learned that our predictions were wrong: the first galaxies grew faster, hotter, bigger, and brighter than we expected. We don’t know yet why we were wrong, and it’s a wonderful challenge to astronomers.

In describing the Big Bang theory, you’ve used the term “expanding universe.” Can you walk us through that — why is that nomenclature most accurate?

This is more accurate than the popular name “big bang” because it sticks to the observations best. The name “big bang” suggests an explosion of a giant firecracker at a place and time in a pre-existing universe. That’s the exact opposite of what astronomers see. We see distant galaxies running away from us at enormous speeds, roughly proportional to the distance; divide the distance by the speed, and get the approximate age of the universe. We have no reason to think the universe has any sort of edge, and apparently there’s no limit to how far we can go in imagination. That’s the idea of infinity. We have no evidence yet that there was anything “before” the “beginning of time;” more likely the question is meaningless. So in that sense there is no “origin of the universe,” only a “history of the universe.”

For many people, space exploration is deeply entangled with existential questions such as our place in the universe and the meaning of life among the cosmos. Do you spend much time considering the philosophical implications of your work? 

I think this is one of the most fascinating aspects of astronomy. So far we know that the Earth is special among all the planets we’ve found, but almost all stars have planets, so we can expect that there are other Earths out there, just very far away and hard to find. From geology we know that there are fossils of early life here on Earth, within a few hundred million years of the first oceans. My guess is that life is a thermodynamic imperative: it will occur whenever conditions are suitable. This is the opposite guess from the popular opinions of previous generations of scientists. The upshot is that I think life is common in the universe, complex life is less common, and civilizations like ours are rare.

As to the great mysteries of consciousness, meaning, morality, spirit, and so forth: I am guessing that other creatures sharing our planet have their own versions, but they don’t speak our languages so we can’t even begin to understand them. The human brain is biological, but we may never understand how it produces the emergent and transcendent phenomena of our social world. I can’t imagine anything we could measure about a brain that would tell us much about the origin of love. Nevertheless, it’s real for us.

You’ve described the work of a scientist as “being in the process of organized curiosity.” How do you see the role of NASA in that process, especially given the common pushback against space exploration, e.g. “Why spend money on space when there are so many problems on Earth?”

Most of the problems of humanity are problems of our relations with other humans — politics, religion, combat, economics. These have unlimited complexity, and science and engineering by design deal with simplified versions. On the other hand, every human problem has technical consequences: climate change, pollution, resource shortages. We can only manage them well if we understand the underlying forces and do our best to find technical solutions to technical problems. When President Kennedy announced that we were going to the Moon with the Apollo program, he said we would do it not because it’s easy but because it’s hard, and then he promised we would do the other things too. The problems of people dealing with people are much more complex than the space program, and can’t be solved by science and engineering alone.

The views and opinions of the author are their own and do not necessarily reflect those of the Aspen Institute.  

By Maya Kobe-Rundio, Associate Digital Editor, Aspen Ideas