An interview about the universe

Einstein@home

The physicist Bruce Allen devotes his research to nothing less than the entire universe.

In 2005, the Year of Einstein, he launched the “Einstein@Home” project. Suffice it to say: he aims to detect signals from space, always on the lookout for gravitational waves. Allen is the director of the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Hannover.

What is the ultimate goal?

We want to detect the first gravitational wave from a rotating neutron star. The gravitational waves discovered in September 2015 resulted from two merging black holes, and we now want to take the next step.

What is Einstein@Home all about?

With the help of computing power from people all over the world, we want to detect signals from rotating neutron stars in space. Satellites and telescopes capture this data, and by combining the power of these computers, we can detect the faint signals contained within it. It’s like sifting through an infinite number of grains of sand to find one that has a very specific shape. To do this, we need enormous computing power. A supercomputer is extremely expensive, which is why we use Einstein@Home to pool the power of a vast number of computers. Together, they are as powerful as the 20 to 30 fastest computers in the world. The data we receive helps us better understand the universe.

How does the search for neutron stars work?

Neutron stars are small, extremely dense objects—a teaspoonful of a neutron star has the same mass as an entire mountain. Some are only 20 kilometers in diameter and rotate very rapidly. Much like a lighthouse that regularly emits a beam of light, they emit gravitational waves, gamma rays, and radio waves. Satellites and telescopes capture this data, and the participants’ computers sift through it for faint signals hidden within. Using the received data, we can locate neutron stars. Every participant who has located a neutron star receives a certificate.

Where are the participants from?

About half a million people from all 193 member states of the United Nations have contributed to Einstein@Home. Most are from the United States, with Germany and the United Kingdom in second and third place, respectively.

How successful is Einstein@Home?

Since the project began, we have detected around 100 new neutron stars based on their gamma rays and radio waves. Unfortunately, in the 14 years since then, we have not yet recorded a gravitational wave from a single neutron star. That’s a real shame, because that is our actual goal. Gravitational waves can, for example, provide us with information about the internal structure of a neutron star. This is very exciting for research in astronomy and nuclear physics.

What are the challenges?

The biggest challenge is finding long-term participants for the project. At first, many people are enthusiastic about Einstein@Home—especially since it’s very easy to join and you can just sit back and relax afterward. But their numbers drop off quickly: for example, because of updates or because a participant buys a new computer. For the research objective, however, it’s important to collect data over a longer period of time.

Are there similar projects around the world?

One of the best-known projects of this kind is SETI@home. Participants pool their internet-connected computers to search for signs of intelligent life beyond Earth.

Interested? Here's how you can easily join Einstein@Home: https://einsteinathome.org/en/home