Stardust

Look: 7 strange facts unlocking secrets of nebulae

These space clouds look like art — but they’re more than their beauty.

NASA, ESA, and the Hubble Heritage Team (AURA/STScI)

NASA, ESA/Hubble and the Hubble Heritage Team

For more than 30 years, the Hubble Space Telescope has been our eye on the universe’s stunning nebulae.

Simply put, a nebula is a giant cloud of dust and gas in space.

Sometimes they appear when a star dies, and other times they are nurseries for new stars.

NASA, ESA, and the Hubble Heritage Team (AURA/STScI)

J.P. Harrington and K.J. Borkowski (University of Maryland), and NASA

Nebulae are as stunning as they are strange. Many mysteries lurk within these cosmic clouds.

Here are 7 strange facts about nebulae:

NASA, ESA, Hubble Heritage Team

7. Some nebulae make their own light.

These are known as emission nebulae. Radiation from stars inside the cloud energize electrons that emit light energy when combining with atoms.

NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team

6. Others reflect the light of their surroundings.

Aptly named reflection nebulae, light from nearby stars scatters in these clouds to create an often bluish color.

NASA and The Hubble Heritage Team (STScI)

5. You can thank solar winds and radiation for their amazing shapes.

Charged particles and energy from stars and other bodies in the vicinity of a nebula determine what form it takes.

ESA/Hubble & NASA

4. Our Sun will become a nebula one day.

In 5 billion years the Sun will run out of fuel and shed its outer layers, scattering a nebula of gas and energy through the Solar System.

NASA via Giphy

3. Some nebulae can be seen with the naked eye.

While most require telescopes to spot, formations like the Orion Nebula are bright enough to see in the night sky without assistance.

Javier Zayas Photography/Moment/Getty Images

2. Not all nebulae are bright.

These are called absorption nebulae, and they block light coming from behind them. They contain more dust than other nebulae.

NASA, ESA, and The Hubble Heritage Team (STScI/AURA); Acknowledgment: P. McCullough (STScI)

1. Nebulae have incredibly low density.

Their particles are spread thin, at as low as 0.1 atoms per cubic centimeter (cc). Comparatively, the particles in Earth’s air contain about 10 million trillion molecules per cc.

NASA, ESA, and K. Stapelfeldt (Jet Propulsion Laboratory); Processing; Gladys Kober (NASA/Catholic University of America)