In this artist’s illustration, turbulent winds of gas swirl around a black hole. Some of the gas is spiraling inward toward the black hole, but another part is blown away.

A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.

Because no light can get out, people can’t see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars.

How Big Are Black Holes?
Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or “stuff,” in an object.

More information on black holes.

Artwork Credit: NASA, and M. Weiss (Chandra X -ray Center) via NASA http://www.nasa.gov/content/black-hole-friday

The International Space Station’s 3-D printer has manufactured the first 3-D printed object in space, paving the way to future long-term space expeditions. The object, a printhead faceplate, is engraved with names of the organizations that collaborated on this space station technology demonstration: NASA and Made In Space, Inc., the space manufacturing company that worked with NASA to design, build and test the 3-D printer.This image of the printer, with the Microgravity Science Glovebox Engineering Unit in the background, was taken in April 2014 during flight certification and acceptance testing at NASA’s Marshall Space Flight Center in Huntsville, Alabama, prior to its launch to the station aboard a SpaceX commercial resupply mission. The first objects built in space will be returned to Earth in 2015 for detailed analysis and comparison to the identical ground control samples made on the flight printer prior to launch. The goal of this analysis is to verify that the 3-D printing process works the same in microgravity as it does on Earth.

The printer works by extruding heated plastic, which then builds layer upon layer to create three-dimensional objects. Testing this on the station is the first step toward creating a working “machine shop” in space. This capability may decrease cost and risk on the station, which will be critical when space explorers venture far from Earth and will create an on-demand supply chain for needed tools and parts. Long-term missions would benefit greatly from onboard manufacturing capabilities. Data and experience gathered in this demonstration will improve future 3-D manufacturing technology and equipment for the space program, allowing a greater degree of autonomy and flexibility for astronauts.

Image Credit: NASA/Emmett Given via NASA http://www.nasa.gov/content/international-space-station-s-3-d-printer