May 2, 2019

Evidence of ripples in the fabric of space found 5 times this month

Miriam Kramer, author of Space

Scientists hunting for gravitational waves — ripples in the fabric of space and time sent out by cataclysmic collisions — have had a busy month.

The impact: The LIGO and Virgo observatories tasked with detecting these waves began their newest observing run on April 1, and they've already found evidence of 5 possible gravitational wave signals. The observatories are 40% more sensitive following upgrades made since the last observing run ended.

The big question: By detecting these gravitational waves on Earth, scientists can work backward to find out more about what created those ripples, giving us new insights into some of the most extreme objects in the universe.

“The entire astrophysics community is very excited that we’ve already seen 5 candidate events in four weeks.”
LIGO astrophysicist Jess McIver said during a press conference Thursday

Details: Three of the gravitational wave signals are thought to be from two merging black holes, with the fourth believed to have been emitted by colliding neutron stars. The fifth, and perhaps most exciting, seems to be from the merger of a black hole and a neutron star.

  • If confirmed, this will mark the first neutron star-black hole merger ever documented.

All five signals still need to be confirmed through follow-up analysis.

How it works: LIGO and Virgo are able to detect these gravitational waves through very precise instrumentation. When a gravitational wave passes through Earth’s part of space, every atom warps ever so slightly.

  • A laser runs down the arms of LIGO and Virgo’s three L-shaped detectors. Once the laser hits the end of the detector, a mirror bounces the light back to the middle.
  • If no gravitational wave has passed through, the beams of light should arrive back at the bend in the L at the same time, but if there’s a mismatch, a gravitational wave may have been observed.

What’s next: Unlike earlier observing campaigns, the two observatories have started releasing their detections in real time, allowing other observatories to make follow-up observations.

Go deeper

Amid racial unrest, a test at the polls

Photo: Stephen Maturen/Getty Images

Eight states plus D.C. are holding primary elections today following a week of intense protests across the country over the brutal police killing of George Floyd.

Why it matters: It's the first major test for voting since the national outcry. Concerns over civil unrest and the police — as well as the coronavirus and expanded absentee voting — could reduce the number of voters showing up in person but heighten tensions for those who do.

Axios-Ipsos poll: America’s big racial divide on police, virus

Data: Ipsos/Axios survey; Note: ±3.2% margin of error; Chart: Andrew Witherspoon/Axios

A new Axios-Ipsos poll finds that America has a massive racial gulf on each of our twin calamities — trust in police, and fear of the coronavirus.

  • 77% of whites say they trust local police, compared with just 36% of African Americans — one of many measures of a throbbing racial divide in Week 11 of the Axios-Ipsos Coronavirus Index, taken the week George Floyd was killed by a white policeman in Minneapolis.
Updated 50 mins ago - Politics & Policy

Updates: George Floyd protests nationwide

Police officers wearing riot gear push back demonstrators outside of the White House on Monday. Photo: Jose Luis Magana/AFP via Getty Images

Protests over the death of George Floyd and other police-related killings of black people continued for a seventh day across the U.S., with President Trump threatening on Monday to deploy the military if the unrest continues.

The latest: Four police officers were struck by gunfire while standing near a line in St Louis on Monday after a peaceful demonstration, Police Chief John Hayden said early Tuesday. They were all taken to hospital with non-life threatening injuries. He said a small group of people had thrown rocks and fireworks at police officers.