Sign up for our daily briefing

Make your busy days simpler with Axios AM/PM. Catch up on what's new and why it matters in just 5 minutes.

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Catch up on coronavirus stories and special reports, curated by Mike Allen everyday

Catch up on coronavirus stories and special reports, curated by Mike Allen everyday

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Denver news in your inbox

Catch up on the most important stories affecting your hometown with Axios Denver

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Des Moines news in your inbox

Catch up on the most important stories affecting your hometown with Axios Des Moines

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Minneapolis-St. Paul news in your inbox

Catch up on the most important stories affecting your hometown with Axios Twin Cities

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Tampa Bay news in your inbox

Catch up on the most important stories affecting your hometown with Axios Tampa Bay

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Charlotte news in your inbox

Catch up on the most important stories affecting your hometown with Axios Charlotte

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

Please enter a valid email.

Please enter a valid email.

Subscription failed
Thank you for subscribing!

An artist's illustration of a "cocoon" in the aftermath of two neutron stars merging. Credit: NRAO/AUI/NSF: D. Berry

The merger of two dense neutron stars millions of years ago produced ripples in spacetime and an afterglow of radiation detected on Earth on August 17. After monitoring the signal for months, a team of astronomers reports today that the X-rays, radio waves and gamma rays emitted from the event may be coming from a cocoon-like structure — the first to be seen.

Why it matters: The origin of short gamma-ray bursts — fast, bright and powerful flashes of radiation from events long ago and far away in the universe — is unknown. A leading theory is they are produced in the merger of neutron stars and black holes that release jets of radiation. The hope then was that observing such jets in an event like researchers did over the summer would confirm the link between neutron star mergers and gamma ray bursts.

"Our continued radio monitoring has confirmed that all this emission was produced by a cocoon. This event, therefore, does not provide direct confirmation of the link between neutron star mergers and GRBs [gamma ray bursts]," Caltech astronomer and study coauthor Gregg Hallinan tells Axios.

The evidence: A jet emission of X-rays and radio waves would be expected to get weaker over time if it was being viewed on Earth from an angle, as researchers originally proposed after observing this particular event — but astronomers report the intensity of the radio waves continued to grow up to 93 days later. They propose the jet could be colliding with surrounding material to create a cocoon that can send light in many directions. This could account for the radio and gamma ray emissions they see.

Yes, but: "The tension is between whether or not you can uniquely explain the observations using this cocooony thing, or whether you can still explain the observation just with a jet with more complexity built into the physics," Daryl Haggard, assistant professor of physics at McGill University, told Gizmodo's Ryan Mandelbaum. "That is completely unresolved."

Go deeper

Woman who allegedly stole laptop from Pelosi's office to sell to Russia is arrested

Photo: FBI

A woman accused of breaching the Capitol and planning to sell to Russia a laptop or hard drive she allegedly stole from Speaker Nancy Pelosi's office was arrested in Pennsylvania's Middle District Monday, the Department of Justice said.

Driving the news: Riley June Williams, 22, is charged with illegally entering the Capitol as well as violent entry and disorderly conduct. She has not been charged over the laptop allegation and the case remains under investigation, per the DOJ.

Biden will reverse Trump's attempt to lift COVID-related travel restrictions

Photo: Tasos Katopodis via Getty

The incoming Biden administration will reverse President Trump's last-minute order to lift COVID-19 related travel restrictions, Jen Psaki, the incoming White House press secretary, tweeted.

Why it matters: President Trump ordered entry bans lifted for travelers from the U.K., Ireland, Brazil and much of Europe to go into effect Jan. 26, but the Biden administration will "strengthen public health measures around international travel in order to further mitigate the spread of COVID-19," Jen Psaki said. Biden will be inaugurated on Wednesday, Jan. 20 and Trump will no longer be president by the time the order is set to go into effect.

Dominion sends cease and desist letter to My Pillow CEO Mike Lindell

Photo: Stephen Maturen/Getty Images

Dominion Voting Systems on Monday sent a cease and desist letter to My Pillow CEO Mike Lindell over his spread of misinformation related to the 2020 election.

Why it matters: Trump and several of his allies have pushed false conspiracy theories about the company, leading Dominion to take legal action. It's suing pro-Trump lawyer Sidney Powell for defamation and $1.3 billion in damages, and a Dominion employee has sued Trump himself, OANN and Newsmax.