Images by Date
Images by Category
Solar System
Stars
White Dwarfs
Supernovas
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Quasars
Galaxy Clusters
Cosmology/Deep Field
Miscellaneous
Images by Interest
Space Scoop for Kids
4K JPG
Multiwavelength
Sky Map
Constellations
3D Wall
Photo Blog
Top Rated Images
Image Handouts
Desktops
High Res Prints
Fits Files
Image Tutorials
Photo Album Tutorial
False Color
Cosmic Distance
Look-Back Time
Scale & Distance
Angular Measurement
Images & Processing
AVM/Metadata
Getting Hard Copies
Image Use Policy
Web Shortcuts
Chandra Blog
RSS Feed
Chronicle
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Space Scoop
Weather Forecast Predicts Rain Around Black Holes

You may have heard of precipitation (pronounced preh-sip-it-AY-shion). It is the fancy name we give to water falling from clouds in the sky, mostly as rain but sometimes as snow, hail or sleet. But would you believe that precipitation is also found in space?

On Earth, precipitation happens when water is heated by the Sun and forms steam (like the steam you see rises from a kettle as the water boils). The steam rises up into the air where it cools down, reforming into tiny droplets of water. These water droplets group together and create the clouds we see in the sky.

Sometimes, something similar happens in galaxies. Clouds of hot cosmic gas cool down, becoming clouds of cold cosmic gas instead. This is also called precipitation. Can you see how the two processes are similar? (Answer: They both create cold clouds.)

However, while precipitation on Earth allows planets and animals to grow, precipitation actually stops the growth of galaxies. At least, it does if the galaxy has a giant black hole at its center.

This is because stars are born from cold clouds of cosmic gas. But in galaxies with central black holes, when a cloud cools down, it is an easier target for a black hole to capture and feed on.

As the black hole feeds it releases a hot jet of energy. The jet then re-heats any nearby clouds of cold gas before they have chance to form into stars.

Cool fact: Collisions between galaxies can cause such intense heat that it "dries up" the precipitation loop for good. Let's hope something similar doesn't happen on Earth!


Watch the video podcast


This is a kids' version of Chandra Release Abell 2597 (March 4, 2015)

Do you want to learn more about this topic?

Visit the Chandra field guide or send us your questions in an email: cxcpub@cfa.harvard.edu




In cooperation with Space Scoop: Bringing news from across the Universe to children all around the world. Universe Awareness and the Chandra X-ray Observatory


Children & Online Privacy
RSS feed