News

  1. Health & Medicine

    Chinese ‘tweets’ hint that happiness drops as air pollution rises

    A study of more than 210 million social media posts reveals a link between people’s sense of well-being and pollution.

    By Sujata Gupta
  2. Planetary Science

    The latest picture of Ultima Thule reveals a remarkably smooth face

    Kuiper Belt object MU69, nicknamed Ultima Thule, is largely unmarred by impact craters, suggesting the Kuiper Belt might lack small objects.

    By Lisa Grossman
  3. Earth

    Earth’s core may have hardened just in time to save its magnetic field

    Earth’s inner core began to solidify sometime after 565 million years ago — just in time to prevent the collapse of the planet’s magnetic field, a study finds.