Aug 1, 2019

The Milky Way in 3D

A map of the Milky Way made using the distribution of pulsing stars. Credit: J. Skowron/OGLE/Astronomical Observatory, University of Warsaw

A new 3D map of the Milky Way reveals the structure of our galaxy as never before, according to a study published this week in the journal Science.

Why it matters: By modeling the Milky Way, scientists can piece together the galaxy’s history, explaining why it looks the way it does and placing it in context with other galaxies observed around our own.

What they found: The new study confirms the Milky Way’s disk appears to be warped in an extreme way.

  • “We don't know for sure, but we think that the warp may have been caused by interactions with satellite galaxies…” Dorota Skowron, one of the study’s authors tells Axios via email. “Other possibilities point to interactions with intergalactic gas or dark matter.”
  • The team measured the distances from the Sun to more than 2,400 pulsing stars called Cepheids in order to map the galaxy from the inside out.
  • They found the Milky Way does have four arms arranged in a spiral structure, as earlier studies have suggested.

What’s next: Mapping variable stars like Cepheids on the other side of the Milky Way’s center could inform future research about the shape of our galaxy, astrophysicist Richard de Grijs, who didn’t take part in the new study, tells Axios via email.

  • If the other side of the disk is also warped “this 3D feature is most likely caused by dynamics and kinematics of the stars in the disk,” de Grijs, who recently co-authored another study mapping the galaxy with Cepheids, said.
  • “If this is only seen on one side, it may be due to the gravitational effects of or merger with a smaller ‘dwarf’ galaxy in the past.”
  • The bottom line: It isn't a complete map of the Milky Way, but it sets a foundation for understanding how our galaxy and others around it evolved.

Go deeper

In photos: Authorities issue warning as Americans venture out for Memorial Day weekend

Venice Beach in Los Angeles on May 24. Photo: David McNew/Getty Images

Authorities urged Americans to maintain social distancing and wear masks against the coronavirus amid reports of packed beaches and bars during the Memorial Day weekend.

Driving the news: Law enforcement stepped up beach patrols, authorities on Florida's Gulf Coast closed parking lots because they were full and there were crowded scenes at Lake of the Ozarks bars in Missouri, per AP, which reports a shooting injured several people at a packed Daytona Beach in Florida.

Coronavirus dashboard

Illustration: Aïda Amer/Axios

  1. Global: Total confirmed cases as of 9:30 p.m. ET: 5,405,029 — Total deaths: 344,997 — Total recoveries — 2,168,408Map.
  2. U.S.: Total confirmed cases as of 9:30 p.m. ET: 1,642,021 — Total deaths: 97,698 — Total recoveries: 366,736 — Total tested: 14,163,195Map.
  3. World: White House announces travel restrictions on Brazil, coronavirus hotspot in Southern Hemisphere Over 100 coronavirus cases in Germany tied to single day of church services — Boris Johnson backs top aide amid reports that he broke U.K. lockdown while exhibiting symptoms.
  4. Public health: Officials are urging Americans to wear masks headed into Memorial Day weekend Report finds "little evidence" coronavirus under control in most statesHurricanes, wildfires, the flu could strain COVID-19 response
  5. Economy: White House economic adviser Kevin Hassett says it's possible the unemployment rate could still be in double digits by November's election — Public employees brace for layoffs.
  6. Federal government: Trump attacks a Columbia University study that suggests earlier lockdown could have saved 36,000 American lives.
  7. What should I do? Hydroxychloroquine questions answeredTraveling, asthma, dishes, disinfectants and being contagiousMasks, lending books and self-isolatingExercise, laundry, what counts as soap — Pets, moving and personal healthAnswers about the virus from Axios expertsWhat to know about social distancingHow to minimize your risk.
  8. Other resources: CDC on how to avoid the virus, what to do if you get it, the right mask to wear.

Subscribe to Mike Allen's Axios AM to follow our coronavirus coverage each morning from your inbox.

Updated 1 hour ago - Politics & Policy

Republicans sue California over mail-out ballot plan

California Gov. Gavin Newsom during a February news conference in Sacramento, California. Photo: Justin Sullivan/Getty Images

President Trump accused Democrats of trying "Rig" November's general election as Republican groups filed a lawsuit against California Sunday in an attempt to stop Gov. Gavin Newsom (D) from mailing ballots to all registered voters.

Driving the news: Newsom signed an executive order this month in response to the coronavirus pandemic ensuring that all registered voters in the state receive a mail-in ballot.