What Makes Planets Form? And Why Don’t They All Look Like Our Own?

Jane Huang, an assistant professor of astronomy, grew up in Chicago, but has no strong feelings on whether New York or her hometown has better pizza. What she does care about is how planets form and why they exhibit such diverse properties—properties often quite different from what we see in our own solar system.

Columbia News caught up with Huang to discuss her latest findings, her ongoing research, and what she likes about living in New York.

What does your latest paper in The Astrophysical Journal examine?

We looked at protoplanetary disks in an area in the Orion constellation that has a massive star nearby that’s irradiating the region with intense ultraviolet light. To our surprise, we found evidence of gaps and rings in most of the disks—structures commonly associated with the formation of giant planets, like Jupiter. It suggests that planets can actually form even in harsh stellar environments that we thought were inhospitable to them forming.

How does that relate to your research more broadly?

I’m interested in how and why planets form and why we see so much diversity in their properties. At this point, astronomers have found thousands of planets outside our solar system, and many look very different from the ones in our solar system, which raises the question of what circumstances give rise to a system like our own versus another kind of system.

I look primarily at protoplanetary disks. Stars form when clouds of gas and dust in space collapse because they’re so massive. Then, as a natural byproduct, the leftover material starts to spin around the new baby star, and that’s a protoplanetary disk. It’s made of gas, dust, and ice. Our own solar system used to have one called the solar nebula. Eventually the material in the disk comes together to make planets, and finally the disk disperses.

My research is looking at these disks and asking all kinds of questions: What is shared between solar systems, and what is unique? Can neighboring stars outside the solar system influence how the planets form? Why do some solar systems have rocky planets, and others only have gas giants? And so on and so forth.

The material in these protoplanetary disks is cold and so dusty that normal optical telescopes can’t see it, so we use radio telescopes to observe it. The one that I use is the Atacama Large Millimeter/submillimeter Array (ALMA). It’s in the desert in Chile.

Are our solar system’s planets unusual?

For a long time the only planets we knew about were in our solar system, and, based on that, people thought that you would always find rocky planets on the inside, close to the star, and ice and gas giants on the outside, as you do in our solar system. But then the first planet around another sun-like star was observed in 1995, and, to scientists’ surprise, it was a Jupiter-mass planet orbiting incredibly close to its star. Another interesting thing is that the most common types of planets in the Milky Way are Super-Earths, which are larger than Earth and smaller than Neptune. These are really common, and one of the big questions is: If it’s seemingly so easy to make planets like that, why didn’t we end up with one here in our solar system, too?

How often do you go to Chile to use the ALMA telescope?

Actually, never. A lot of people imagine that astronomers spend their nights sitting at a telescope. It’s not the case for most of us. What we do is we request usage of time on the telescope, and there’s a competitive process, and then the proposals are executed by the observatory. Still, if the opportunity arises, I would love to see it in person.

You joined Columbia in 2023. How do you like living in New York so far?

It’s great. I’m very happy to have access to the astronomy resources around here and to interact with scientists at nearby institutions like the Flatiron Center for Computational Astrophysics and the American Museum of Natural History.

On a more personal level, I love the cultural offerings of the city, like the Metropolitan Museum. Growing up, I was a huge fan of From the Mixed-Up Files of Mrs. Basil E. Frankweiler, a novel about a girl and her brother who sneak into the Metropolitan Museum. I’ve never been tempted to do that myself exactly, but I really like the spirit of the girl wanting to learn something for herself, and being very research-minded and very scientific in her approach.

You’re a Chicago native. Do you miss the pizza?

This is going to sound sacrilegious but I don’t have a particularly strong opinion at all on pizza or hot dogs. New York does have great food. I’ve particularly enjoyed the Hungarian Pastry Shop and WAU, an Indonesian place on the Upper West Side.