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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

Ben Geman, author of Generate
11 mins ago - Energy & Environment

White House moves against "super-pollutant" in climate fight

Photo: Kena Betancur/VIEWpress/Corbis via Getty Images

The EPA is finalizing rules today that cut powerful greenhouse gases used in air conditioning and refrigeration, part of a wider new White House strategy to deter these "super-pollutants" and boost manufacturing of substitutes.

Why it matters: The EPA regulation is the U.S. part of a planned global phase-down of chemicals called hydrofluorocarbons. The global phaseout can prevent up 0.5 °C of global warming by 2100, the White House said.

FBI report likely to show record increase in murders in 2020

Illustration: Aïda Amer/Axios

If the FBI data released next week shows what's expected — that 2020 saw the highest single-year spike in U.S. murders in at least six decades — experts say the sudden job losses, fears and other jolts to society at the start of COVID-19 will likely have been the overwhelming drivers.

Why it matters: Many Democrats already feared that rising crime could hurt their party in the 2022 midterms.

44 mins ago - Health

Some experts see signs of hope as COVID cases fall

Expand chart
Data: N.Y. Times; Chart: Kavya Beheraj/Axios

New coronavirus cases are continuing to decline, and some experts are cautiously optimistic that the virus will continue to wane even into the fall and winter.

The big picture: The next few months are highly uncertain, and some localized outbreaks are all but guaranteed. But the U.S. is at least moving in the right direction again.