Gravitational waves, in the words of MIT researchers

MIT physicists gathered in the Bush Room under MIT’s dome on Feb. 11 to share some important news. The world knows what came next: in parallel with an event at the National Science Foundation, the scientists announced their breakthrough in making the first direct observation of gravitational waves. The cause of the waves was equally spectacular: a billion years ago, two black holes collided and outputted 50 times more power than all the suns in the universe.

The announcement was a triumph for basic research in science and a stellar example of the collaboration required for such technological advances: more than a thousand people worked together at the Laser Interferometer Gravitational-Wave Observatory (LIGO).

In the minutes leading up to the Bush Room announcement, emotions were running high for the MIT LIGO researchers present. Nothing had officially been stated, but everyone knew: this was big.

The Tech had the opportunity to talk with a few of the researchers involved, minutes before the news would go live, and listen to their raw views on the scientific and technological breakthrough.

Nergis Mavalvala — an MIT professor and the Associate Department Head of Physics, who played a prominent role in the LIGO research — shared her thoughts. Sebastien Biscans and Fabrice Matichard are two research engineers at LIGO who were also present at the announcement.

The Tech: Why is this important for science?

Mavalvala: I think the real importance of having made this detection of gravitational waves from binary black holes is … there’s three things there:

Gravitational waves: they exist, we can detect them, we have detectors that are finally sensitive to do so.

Binary black holes, that are 30 times more massive than our own sun. This is a mass range that we hadn’t confirmed could really be there. The fact that they behave exactly as general relativity would predict is an amazing affirmation of the theory.

Finally, and most important to me, we’re opening a new window into the universe and how we might be doing astronomy 10 years from now, 30 years from now, 100 years from now.

The Tech: I’m curious how this changes your research, and also if this changes anything about MIT physics?

Mavalvala: I think the way that it changes my research is that we now have some direction to go in, in terms of the astrophysics, but also in terms of the instrument kit. Most of my work over my career has been on making better and better detectors, and this sort of informs people like me, where do we need to put our resources? Do we need a better detector at low frequencies? At high frequencies?

I actually think the biggest changes are yet to come, because, you know, we’ve detected the very first things. Imagine if in the next observing run, we see something and we have no idea what it is.

I think it’s wide open still, even though we have some guidance now that we didn’t have before. We’re still moving ahead trying to make better and better instruments.

The Tech: When you got into this work, did you ever imagine that your work would help lead to something like this?

Mavalvala: You know, yes and no. I started as a graduate student in gravitational waves, with Rai Weiss. And you know, we believed it was around the corner. Twenty-five years later, we’ve done it, but if I had known it was 25 years, maybe I wouldn’t have started. But the truth is once I started, it was really an amazing thing to work on, in part because of the payoff of being able to open up this new window into the universe, but also in part because of the sheer level of technological prowess that’s needed to pull this off. I was really wowed by all the people I worked with. I would do it again even if I knew it was going to be 25 years more.

The Tech: What’s your role in this?

Biscans: We’re part of the LIGO team here at MIT. Personally, I’ve been working for 6 years on the project, especially on the platform where the optics and all the interferometer is built on: what we call the seismic platform ... It’s to prevent the ground motion from making too much noise for the mirrors.

Matichard: I was a lead engineer on the seismic isolation systems, leading design and testing, and the installation of all the platforms needed.

The Tech: What was the overall collaboration like? How many people were involved?

Biscans: I don’t know the exact number, but a lot — more than a thousand.

Matichard: We’re organized into groups. For example, in our case, we’re the group in charge of seismic isolation, and we have partners in Stanford and in other universities. There are some subgroups on each site. Several times a week we meet on teleconference.

Biscans: You have people from all over the world and different backgrounds. I think that’s why the project is great, because you’re working with so many different people from all around the world.

The Tech: How would you explain the importance of this discovery to the public?

Biscans: To be very general, right now, one of the only ways we have to observe the universe is looking at light, and this is a totally new way to look at the universe. We call that the sound of the universe. Gravitational waves are kind of the sound of the universe. It’s like a totally new approach and new way to observe the universe, and hopefully by having this new way of observing the universe, we’re going to answer other cosmological questions. So it’s a totally new path, a new way in astrophysics. That’s why I think it’s awesome.

Matichard: And obviously, it’s a first direct detection of those gravitational waves predicted by the theory of general relativity of Einstein.

Biscans: One hundred years!

This interview has been edited and condensed for clarity.