LIVINGSTON -- 2025 marks a special year for LIGO Livingston. On September 14, it will mark the 10th anniversary of the Observatory detecting gravitational waves on Earth for the first time. The waves were produced from the merger of two massive black holes.

"The first one we saw, the two things that were in orbit around each other, were black holes each weighing as much as 30 suns," LIGO Livingston Observatory Head Joseph Giaime said.

The two black holes were more than a billion light-years away. That means they were detecting something that happened over a billion years ago.

Since the discovery, LIGO has observed hundreds of black holes. However, it's not limited to just detecting black holes. LIGO also observes neutron stars.

"A neutron star is when the content of a stellar core gets compressed to the point where it's all the same material as the atomic nucleus. Really, really, really dense, but not so dense like a black hole, so light can escape a neutron star," Giaime said.

Nestled among the pine trees in Livingston, LIGO recently finished a multi-month observation where it observed many black holes and neutron stars. Giaime says they were some of the biggest the observatory had seen.

"The area between the mass range between neutron stars, which are smaller, and black holes, which are heavier, people hadn't observed anything, and we have seen some things, some objects in that zone of mass that hadn't been seen before."

LIGO Livingston is one of only two active observatories in the nation that detect gravitational waves. The other is LIGO Hanford, which is situated in Washington state. It's funded primarily through the National Science Foundation while being operated by the California Institute of Technology along with the Massachusetts Institute of Technology.

LIGO, or the Laser Interferometer Gravitational-Wave Observatory, says they can best be described by two 4-kilometer-long tunnels that are easy to spot. They're referred to as arms. Inside each arm is a long vacuum tube. Inside the tubes, a laser beam is split in half by a component called a beam splitter. The beams are split and travel through both arms, with each beam being precisely the same length. The beams then bounce off special mirrors at the end of the tubes.

Giaime says these mirrors are very sensitive and are isolated from vibration so that they only feel gravity. In each arm, the laser bounces back and forth between the two mirrors about 100 times before coming back to rejoin the other laser beam. This recombination allows the detector to measure the difference between how the laser traveled.

However, when a gravitational wave passes through, which is essentially a ripple in space, usually resulting from colliding black holes or neutron stars, it distorts space, slightly stretching one arm while squeezing the other. It continues to switch between each arm as the wave passes through. All of these parts working together is how LIGO detects gravitational waves. Picture throwing a rock at a pond and seeing the little waves that spread out across the water.

As far as what's next for Livingston, they said their detector will probably be down for most of 2026 and 2027.

"We've been running for a couple of years now. We're gonna shut down probably at the end of the year to make some improvements that we've been planning for a long time. We'll probably be down for most of 2026 and 2027. The year after that, we'll restart some number of months into that year. Of course, this all depends on funding and if things go well.

LIGO Livingston will still be open during that time, still giving its popular tours of the facility. One of the most popular places is its Science Education Center, with Science Saturday now being on the first Saturday of each month. The next Science Saturday is June 7.