Star clusters are common structures throughout the Universe, each made up of hundreds of thousands of stars all bound together by gravity. This star-filled image, taken with the NASA/ESA Hubble Space Telescope's Wide Field Camera 3 (WFC3), shows one of them: NGC 1866.
Nerve cells (yellow) that make up a heart's brain cluster around the top of this reconstructed rat heart, near where blood vessels enter and exit the organ. Other colors show the contours of distinct heart areas, such as the left atrium (green), right atrium (teal), left ventricle (blue) and right ventricle (purple).
Hubble has taken this stunning close-up shot of part of the Tarantula Nebula. This star-forming region of ionised hydrogen gas is in the Large Magellanic Cloud, a small galaxy which neighbours the Milky Way.
Despite having only half of a brain, certain neural connections appear to be stronger than those in a fully intact brain, a new study suggests.