The annual massive coral spawning of Australia's Great Barrier Reef is underway.
Why it matters: Scientists are concerned that recent severe bleaching at the world’s largest coral reef may limit the size of the phenomenon, the Australian Broadcasting Corporation reports. The health status of the World Heritage-listed ecosystem has worsened from "significant concern" to "critical" for the first time, a new report finds.
Why it matters via Axios' Miriam Kramer:It's only the second time pristine asteroid material has been brought back to Earth. Sample return missions like this one are incredibly valuable to scientists.
