What can old stars teach us about the birth of our galaxy?

These needles in the vast galactic haystack take more effort to find, but they help piece together our origins.

  • With billions of stars in our galaxy, why should astronomers seek out the oldest ones?
  • Age-dating stars is a complicated process, so astronomers use chemical compositions, telescopes, and prisms to determine the age of these ancient stars.
  • Some telescopes used for this purpose are in extremely remote places, where you can observe the bright band of the Milky Way with the naked eye.
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The TESS satellite caught a comet ‘burp'

What happens after a heavy comet meal?

Image source: Farnham et al./NASA
  • A comet produces and unexpected explosive ejection of ice, dust, and gas.
  • NASA's TESS satellites captures the whole thing by accident.
  • The "burp" may have left a crater 65 feet across. That's quite a burp.
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New study says cosmic acceleration and dark energy don't exist

An Oxford scientist claims a Nobel-Prize-winning conclusion is wrong.

NASA
  • Paper by Oxford University physicist Subir Sarkar and his colleagues challenges how conclusions about cosmic acceleration and dark energy were reached.
  • Physicists who proved cosmic acceleration shared a Nobel Prize.
  • Sarkar used statistical analysis to question key data, but his methodology also has detractors.
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Astrophysicist claims "dark fluid" fills the missing 95% of the Universe

An Oxford scientist's controversial theory rethinks dark matter and dark energy.

Credit: YE AUNG THU/AFP/Getty Images.
  • An astrophysicist and cosmologist Dr. Farnes published a paper while at Oxford University with a novel explanation for dark energy and dark matter.
  • His theory claims to explain the missing 95% of the observable universe by the existence of "dark fluid".
  • This fluid has negative mass, repelling other materials.
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Student of the stars: How do you become an astronomer?

NASA astronomer Michelle Thaller explains what astronomers actually do, and how can you become one.

  • What's the difference between an astronomer and an astrophysicist? NASA's Michelle Thaller explains that these terms are used interchangeably: both are physicists who study objects and phenomena in the sky.
  • How can you become an astronomer? There is a defined path to take: Do an undergrad degree in astrophysics, physics, mathematics or computer science, then complete a doctorate in astrophysics. You could also work with astronomers by studying engineering and building telescopes.
  • In this fascinating explanation of what an astronomer's day-to-day job actually looks like, Thaller shines a light on the unexpected skills you might need and answers the question on every ambitious astronomer-to-be's mind: How will I know what to discover?