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Nebula

A nebula is a giant cloud of gas (mostly hydrogen and helium) and cosmic dust situated between stars in the interstellar medium. Nebulae serve as sites of stellar birth and death—including emission nebulae that glow from ionized gas, reflection nebulae that scatter starlight, and dark nebulae that obscure background stars.

Source: science.nasa.gov

APODs including "Nebula"

The Vela Pulsar's Dynamic Jet

03/07/2003

The Vela Pulsar's Dynamic Jet
Image Credit: NASA Astronomy Picture of the Day

The Vela pulsar is a neutron star born over 10,000 years ago in a massive supernova explosion. Above, false-color x-ray images from the Chandra Observatory reveal details of this remnant pulsar's x-ray bright nebula along with emission from a spectacular jet of high-energy particles. In this time-lapse series of pictures, the jet seems to dance around very much like an out-of-control firehose, shooting along the pulsar's direction of motion (toward the top right corner) to a length of about half a light-year while whipping back and forth at about half the speed of light. Highly magnetized and spinning over 10 times a second, the Vela pulsar is thought of as a cosmic high-voltage generator, powering the x-ray nebula and dynamic cosmic jet. A mere 800 light-years away the pulsar itself is located near the lower left corner in the four panels.