Massive gravitational waves are shaking space

Waves travel through space at the speed of light. However, the wave may take years or decades to pass the Earth.

It can span several light years from one wave crest to the next.

Scientists have now found strong evidence for such low-frequency gravitational waves.

waves after collision

They are hypothesized to be the result of encounters between supermassive black holes at the center of galaxies.

Perhaps there is also something else masking the cosmic fluctuations.

Read also

This planet is not what scientists think

Gravitational waves are ripples in space-time that occur, among other things, when two objects in space orbit each other and crash.

Waves are formed, similar to when you throw a rock into a body of water. But gravitational waves cause space itself to stretch and compress slightly.

bass version

The first direct observation of gravitational waves was made in 2015 with the LIGO facilities in the USA.

Since then, scientists have measured nearly 100 events where two objects orbited each other and merged. According to the ScienceAlert website. The events originated from encounters between black holes or neutron stars. These are the remnants of stars that have died.

When gravitational waves pass through a LIGO facility, they are stretched and compressed almost imperceptibly. LIGO can record a change of one in a thousandth of a proton.

Observatories on Earth can only detect gravitational waves at certain wavelengths.

It would be like if astronomers could only see X-rays with their telescopes. Then they will lose a lot of information about the universe.

It is highlighted in press release From the NANOGrav collaboration.

Using the galaxy as an observatory, this group, along with groups from Australia, Europe, India and China, found strong evidence of low-frequency gravitational waves.

It becomes like the bass issuing space-time ripples, like a bouncer prescribe it.

More groups

nanograph, North American Nanohertz Gravitational Wave Observatory, is a collaboration that studies gravitational waves using pulsars. Pulsars rotate rapidly around neutron stars.

The collaboration consists of more than 190 researchers from the USA and Canada.

In a group of publications in the journal Astrophysical Journal Letters, They describe findings based on data from 67 pulsars over a period of 15 years.

Research groups in Australia, Europe, India and China simultaneously released their findings, which are based on fewer pulsars. Data from all groups point in the same direction.

Researchers have previously found signs of a background of gravitational waves.

Germano Nardini says the evidence is now safer. He does research at the University of Stavanger and works himself with gravitational waves.

The news was not unexpected.

—but of course it’s very good, Nardini tells forskning.no.

Not completely nailed

Sigma is used in some sciences as a measure of the extent to which results are statistically certain.

New discoveries have not yet reached the 5 Sigma level, which is a 99.99 percent statistical certainty and considered the gold standard for being able to say that a discovery has been confirmed.

It’s like rolling a die and getting a six each time. And Nardini explains that there’s less and less chance of it being accidental.

The probability that new results are caused by chance is now 1 in 1,000.

– It’s very high, but it’s not an official discovery, because we need a bigger number. But we’re so close, Nardini says.

Work is underway to analyze data from all collaborations around the world. Results will appear in about a year. Writes for The New York Times. Xavier Siemens, part of the NANOGrav team, predicts that they will go beyond 5 Sigma next.

beacon in the room

The researchers used a number of telescopes to observe pulsars in the Milky Way.

Pulsars can rotate several hundred times per second and emit radio radiation from the poles. When the rays sweep across the Earth, scientists can measure them. The blinking lights tick like a super accurate clock.

By observing many of these pulsars over a longer period of time, researchers can detect huge gravitational waves in the universe.

Gravitational waves stretch and compress space slightly. This means that the radiation from pulsars has to travel a little longer or a little shorter. Creates patterns with the difference of time.

Nardini says research collaborations from different countries cover different parts of the sky.

– The pulsars seen in the United States and Canada are different from those seen in Australia.

galaxies that are shattering

The signals differ from those detected before in several ways.

With LIGO, gravitational waves from an event are measured. Nardini says LIGO captures the final stage of two black holes orbiting each other and colliding.

LIGO can pick up gravitational waves from black holes that are as massive as the sun or a few dozen times heavier.

The new signals are thought to come largely from supermassive black holes. It is much larger, hundreds of thousands to millions of times the mass of the Sun.

Not only do the signals come from the brief moment they collide, Nardini says, but they start much earlier. Supermassive black holes can orbit each other for millions of years before merging.

– Supermassive black holes are expected in the center of galaxies, so we are talking about the collision of galaxies.

background noise

The signals the researchers discovered do not originate from a single event.

The waves come from the supermassive black holes that dance around each other everywhere in the universe.

Imagine that you are on a soccer field. What LIGO does is measure the person who is speaking loudly in the stands, very close to you.

Using pulsars, the researchers instead measured the total noise coming from all the people in the arena.

– They cannot distinguish between an individual. There are thousands of people talking.

However, it may eventually be possible to discern supermassive black holes, According to a press release from NANOGrav.

Another exciting thing, Nardini says, is that you’re not sure if the sound you’re hearing is just coming from the soccer field or if it also originates from something going on outside.

– This sound could be from the early universe, before black holes formed.

Nardini says this will be an important discussion in the coming years.

What is hidden in the signs?

The background signal is stronger than the researchers expected.

“It’s really on the high end of what our models can create from only supermassive black holes,” says NANOGrav’s Chiara Mingarelli. In a press releaseg.

This could mean that there have been more and heavier supermassive black holes merging than expected.

Or, gravitational waves from other sources could have interfered.

What can we learn in the future from background noise in the universe?

– It was said that LIGO opened a new window on the universe. But the point is, LIGO has measured only a fraction of the frequencies of gravitational waves, Nardini says.

He adds that pulsar experiments measure gravitational waves of very different frequencies from other sources.

– What can we learn? The opportunities are huge, Nardini says.

You can identify clusters of supermassive black holes in the universe, and you can understand the dynamics of the supermassive black holes orbiting each other and how they formed, Nardini says.

This is one aspect and another that may come from outside the football arena. This could be even more amazing, says Nardini.

New physics?

Some of the noises may be related to the creation of the universe.

We don’t have direct measurements of what happened in the early minutes of the universe.

Moreover, it is possible that hints of new physics are hiding in the background noise.

The current model predicts that there should be no sound on the outside of the arena that is loud enough to be heard.

– If we hear this sound, it means that our knowledge of particle physics and cosmology is not complete.

Nardini adds that he thinks it’s a shame that Norway didn’t participate in pulsar collaboration or participate in LIGO from the start.

He points out the importance of investing in basic research that may not produce results for decades, but leads to some of humanity’s greatest achievements.