Jun 17, 2017

Why Earth might have had two suns at one point

NASA/JPL-Caltech/UCLA

There is new evidence to support the hypothesis that all stars are "born" with at least one "sibling" — including our sun.

Why it matters: "Our work is a step forward in understanding both how binaries form and also the role that binaries play in early stellar evolution," said UC Berkeley astronomer Steven Stahler.

Two explanations for star pairs:

  1. The two or three stars that are commonly found at the center of planetary systems fall into place together after they form.
  2. The stars at the center of a planetary system are "born" together as "siblings" — this is the favored hypothesis, and the one the new study supports.

The finding: Scientists looked at data from a dust cloud's radio waves in the Perseus constellation that had a host of baby stars. They found that the younger class of stars were closer to their "partners," while some drifted apart as they got older. The scientists then created several simulations of different ways the stars could form. The model that had stars and their twins forming at the same time produced numbers closest to what is observed.

Throwback: Since the 80s, people have speculated that the sun used to have a twin star that shared the center of our universe, even going so far as to name it "Nemesis" and blame it for the extinction of the dinosaurs.

Go deeper

Coronavirus could hit developing countries hardest

Disinfecting in Dakar, Senegal. Photo: John Wessels/AFP via Getty Images

The coronavirus is spreading most widely in countries that should be among the best equipped to handle it. There's no reason to expect that to remain the case.

Where things stand: 88% of new coronavirus cases confirmed on Wednesday came within the OECD club of wealthy nations, which together account for just 17% of the world's population. While that data is based on uneven and inadequate testing, Europe and North America are clearly in the eye of the storm.

Go deeperArrow4 mins ago - World

The Humanity First push for a coronavirus vaccine

Illustration: Aïda Amer/Axios

Policy responses to the global coronavirus crisis have been every-country-for-itself and — in the case of the U.S. and China — tinged with geopolitics.

The flipside: The scientific work underway to understand the virus and develop a vaccine has been globalized on an unprecedented scale.

Go deeperArrow12 mins ago - World

Trump attacks Schumer for impeachment in letter about coronavirus crisis

President Trump briefs reports on April 2. Photo: Win McNamee/Getty Images

President Trump accused Senate Minority Leader Chuck Schumer of being "missing in action" during the coronavirus crisis, writing in a scathing letter on Thursday that Schumer's focus on the "ridiculous impeachment hoax" resulted in New York being ill-prepared for the pandemic.

Why it matters: It's a blistering response to Schumer urging Trump to assign a senior military officer to enforce the Defense Production Act to produce more medical supplies.