SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/astro-xray-needs-space

Why must X-ray telescopes like Chandra orbit above Earth's atmosphere?

The atmosphere absorbs X-rays before they reach the ground.

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  1. X-rays are too faint to see from the ground
  2. The atmosphere absorbs X-rays ✔
  3. X-rays are blocked by city lights

Why: X-rays can pass through skin, but the huge number of atoms in our air stops them. That is good for our health, but it means X-ray astronomy only works from space.

Huh, didn't know that: Chandra's orbit takes it up to 139,000 km above Earth.

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Chandra goes to great heights to get a clear picture.
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References

Answer: The atmosphere absorbs X-rays. X-rays can pass through skin, but the huge number of atoms in our air stops them. That is good for our health, but it means X-ray astronomy only works from space.

  1. Chandra X-ray Center, About Chandra chandra.harvard.edu/about
    Because X-rays are absorbed by Earth's atmosphere, Chandra must orbit above it, up to an altitude of 139,000 km (86,500 mi) in space.
    Checked 2026-10-10.

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