Where will Nobel-winning work on observatory lead us? – News – The Columbus Dispatch

This year, the Nobel Prize in Physics was awarded for the discoveries by LIGO, the Laser Interferometry Gravitational Observatory.

The name is a bit of a mouthful, but the important thing to know is that LIGO is a new type of observatory that can detect minute vibrations in space-time. Such vibrations are given off, for example, when two black holes merge.

Other than the mere fascination of what black holes can do, what good is LIGO? Does it provide any useful spin-offs that society can use?

The answer is maybe, or even probably. Like many new inventions, the ability to harness new technology often takes many years to find its way into applications. Before going there, let’s explore how LIGO works.

What LIGO does really well is measure distances. It does this by shooting a laser beam down two perpendicular tubes to a mirror about 2.5 miles away. When the light bounces back from each mirror, it is recombined, and the difference in length between the two paths is measured from the resulting interference pattern. The amazing thing is that LIGO can measure this path difference to much less than the size of a proton.

Let’s think about that. Consider the width of a human hair. An atom is about 100,000 times smaller than that. And a proton is about 100,000 times smaller than an atom. That’s how precisely LIGO can measure distances.

In the past, when measurement devices have improved, new applications have followed. While I don’t know what gadgets will come from this new technology, it’s clear that LIGO has made a phenomenal advance in measuring lengths.

This advance in technology probably wouldn’t have happened without the motivation of astronomers to explore what’s out there in the universe. In the pursuit of pure knowledge, technological advances happen.

In this case, the astronomers wanted to know whether gravitational waves are emitted when two objects, like black holes or neutron stars, merge. Knowing the kind of mergers that are possible and the rate at which they occur tells us more about the formation of the universe.

Before LIGO measured it, no one knew whether medium-size black holes (with masses equal to tens of our Sun’s mass) existed in pairs. Since black holes are, after all, black, you can’t see them directly with a telescope. We can only infer that black holes exist because of their effect on other astronomical objects, such as stars that orbit black holes.

Astrophysicists are still debating what we learn from LIGO’s data on black holes. It’s possible that stars with larger masses than previously expected could have occurred in the early universe, which would affect models of how stars can form. But until we get more data from LIGO about the mass distributions of black hole mergers, this is just speculation.

Even though the Nobel Prize goes to just three scientists, it takes a large collaboration of people to make LIGO work. The scientists came up with the concepts of how to build it, but a lot of engineers contributed to making it a working apparatus. Also, there is a cadre of computer scientists, electricians, graduate students and so on that contributed to LIGO’s success. The prize is, by design, awarded to three people, but really it belongs to the whole LIGO collaboration.

It is rare that a Nobel Prize is awarded so soon after a discovery. Often, Nobel Laureates receive the prize for work done decades earlier. It is a tribute to the importance of LIGO’s confirmation of Einstein’s theory that it got the prize within about two years of its discovery of gravitational waves.


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