Pieces of the asteroid Vesta on Bennu magnified. Photo: NASA/Goddard/University of Arizona

Scientists have found pieces of asteroid Vesta on asteroid Bennu's surface.

Why it matters: The new finding — detailed in the journal Nature Astronomy — gives researchers some insight into the origins of Bennu, a space rock that's actually a collection of rubble that came together after a huge collision, NASA said.

How it works: Scientists found evidence of the rocks from Vesta in photos taken by OSIRIS-REx, a spacecraft in orbit around Bennu now.

  • The Vesta boulders contain a mineral known as pyroxene that's produced in high heat and likely didn't come from Bennu.
  • "Our leading hypothesis is that Bennu inherited this material from its parent asteroid after a vestoid (a fragment from Vesta) struck the parent," NASA's Hannah Kaplan said in a statement.
  • That parent asteroid was then broken apart and eventually some of its material — including those bits of Vesta — coalesced into Bennu, Kaplan added.

The big picture: The asteroid belt is a messy place. Asteroids often show signs of interactions with one another. Vesta, for example, has dark material on the walls of its craters that is thought to come from another object.

  • Scientists think Bennu — which now has an orbit similar to Earth's — came from the inner part of the main belt of asteroids between Jupiter and Mars.
  • "There are two inner Main Belt asteroid families (Polana and Eulalia) that look like Bennu: dark and rich in carbon, making them likely candidates for Bennu's parent," NASA said.

What's next: OSIRIS-REx is expected to touch down on Bennu next month to collect a sample that will be delivered back to Earth in 2023.

Go deeper

Miriam Kramer, author of Space
Oct 20, 2020 - Science

NASA will attempt to snag an asteroid sample today

Bennu as seen by OSIRIS-REx. Photo: NASA/Goddard/University of Arizona

NASA will attempt to grab a sample from an asteroid tonight.

The big picture: Scientists hope the sample from the asteroid Bennu will allow them to learn more about the early days of the solar system and how it has evolved over billions of years.

Amy Harder, author of Generate
5 hours ago - Energy & Environment

Climate change goes mainstream in presidential debate

Photo illustration: Aïda Amer/Axios. Photo: Olivier Douliery-Pool/Getty

The most notable part of Thursday’s presidential debate on climate change was the fact it was included as a topic and assumed as a fact.

The big picture: This is the first time in U.S. presidential history that climate change was a featured issue at a debate. It signals how the problem has become part of the fabric of our society. More extreme weather, like the wildfires ravaging Colorado, is pushing the topic to the front-burner.

Finally, a real debate

Photo: Morry Gash/AP

A more disciplined President Trump held back from the rowdy interruptions at tonight's debate in Nashville, while making some assertions so outlandish that Joe Biden chuckled and even closed his eyes. A Trump campaign adviser told Axios: "He finally listened." 

The result: A real debate.