Is the soil in Limburg suitable for Einstein’s ultra-sensitive telescope?

• Francine Intema

  internal editor

It should become a scientific instrument of the same caliber as the particle accelerator at CERN: the “Einstein telescope”. European scientists want to catch so-called gravitational waves with kilometers of underground pipe system in the shape of a triangle. Soil research has recently begun to determine if the border region between the Netherlands, Belgium and Germany is really suitable for an observatory.

Gravitational waves became world news in 2016. A hundred years after Einstein predicted the existence of those microwaves, scientists finally noticed them. Somewhere in the universe two black holes collided and released so much energy that it caused “ripples in space-time”. Space has been stretched and compressed a bit. This was measured on Earth with a very sensitive instrument.

With these gravitational waves, scientists have, as it were, a new sense for observing the universe. “It’s like sitting in a Concertgebouw and suddenly not only seeing what’s happening on stage, but also hearing it,” researcher Jo van den Brand said in 2016.

Watch NOS op 3’s explanation of the 2016 news here:

Dozens of gravitational waves have been measured since 2016, but scientists want more. “Now we’ve lifted a corner of the veil, but we want to map the entire universe,” says Stan Bentvelsen, scientific director of the Einstein Telescope Project Office. “How many black holes and stars collide? And are there, for example, other phenomena that emit gravitational waves, such as wormholes? “

Scientists also want to shelve Einstein’s general theory of relativity. “This theory describes very accurately what gravitational waves should look like. We want to test this theory more often in extreme events like colliding black holes. Will it hold up?”

To be able to measure more gravitational waves, a number of European countries would like to build a new detector: Einstein telescope. It must receive thousands of times as many waves as the detectors that made world news, Bentfelsen says. “We count on dozens of new views every day.”

Where the tool should go is still not specified. Dutch scholars want him to come to the border area of ​​the Netherlands, Belgium and Germany and the government has supported this plan. The National Growth Fund has made available 42 million euros 870 million for construction Reserved when you get there.

The tool is estimated to cost around €2 billion, but the Growth Fund expects the project to boost employment in the region and for the technology to be applicable on a larger scale.

“To reduce disturbances, we want to build the Einstein telescope 200 to 250 meters underground,” Bentvelsen says. “It would be a 10 by 10 by 10 kilometer tube system, shaped like a triangle. The beauty of the area we’re looking at now is that the top soil layer is relatively soft and dampens vibration. In the hard rock layers below, we can build tunneling and tool building.”

Earth scientists will investigate whether this is possible within the next two years. “We want to know if the upper layer absorbs enough vibrations and if the hard rock is stable enough to dig tunnels,” says geophysicist Wim Wook. A team of geologists will, among other things, drill holes 250 to 300 meters deep at least ten locations to see what rocks are in the soil.

Gravitational waves are very subtle; Einstein thought no one would notice them. This is why there are devices at the bottom of the wells that measure whether it is calm enough there. The target area is the province of Limburg Wind farm plans Refrigerated because it makes noise.

Geophysicist Walk does not expect problems from earthquakes occurring in the area. “The telescope is built so that it does not suffer from this and does not break down. In the event of an accidental earthquake that is slightly larger, the researchers do not use the observations of that moment.”

Although it is not yet certain that the detector will be in the area, the companies are already working on the necessary technology. Jorg van der Meij of the Limburg Regional Development Agency (LIOF) has been scouting companies that could develop components from 2021.

Meanwhile, a laboratory has sprung up at Maastricht University: the Einstein Pathfinder Telescope. “Before you can use the technology in the Einstein telescope, you have to make sure everything is working properly,” says Bentfelsen, scientific director. “In this lab we can properly test ingredients.”

It will certainly be 2035 before the first gravitational waves are observed with the new instrument, and the Einstein Telescope project country ministries will likely decide around 2026 where they will go. Other possible sites are Sardinia And maybe too Saxony.