The Hubble Space Telescope celebrates its 29th anniversary on 24 April, an event NASA is marking by the release of a spectacular image of the Southern Crab Nebula in the constellation Centaurus that shows dual cones of gas blown off by a central red giant streaming away into space and giving the appearance of a crab floating in the void.
The NASA/ESA Hubble Space Telescope has detected superhot blobs of gas, each twice as massive as the planet Mars, being ejected near a dying red giant star in the V Hydrae binary system. The plasma balls are zooming so fast through space it would take only 30 minutes for them to travel from Earth to the Moon.
While truly massive stars go out in a blaze of glory, intermediate-mass stars — those between roughly one and eight times the mass of the Sun — are somewhat quieter. Such stars eventually form cosmic objects known as planetary nebulae, so named because of their vague resemblance to planets when seen through early, low-resolution telescopes.
Despite their name, planetary nebulae have nothing to do with planets. They were described as such by early astronomers whose telescopes showed them as glowing disc-like objects, but we now know that they represent the final stage of activity of stars like our Sun. A way of estimating more accurate distances to planetary nebulae dispersed across our Galaxy has just been announced.