US-based space agency NASA has marked Halloween by releasing a stunning image of the remains of a “ghostly visage”. The glowing gas cloud is described by NASA as “haunting Earth’s sky toward the constellation of Cygnus and form the Veil Nebula.” The nebula is a large supernova remnant, an expanding cloud born of the death explosion of a massive star.
Light from the original supernova explosion likely reached Earth more than 5,000 years ago.
Also known as the Cygnus Loop, the Veil Nebula now spans nearly three degrees, approximately six times the diameter of the Full Moon.
This translates to more than 70 light-years at its estimated distance of 1,500 light-years.
The Veil is so large its brighter parts are actually recognised as separate nebulae, including The Witch’s Broom (NGC 6960), found below and right of centre.
The bright star 52 Cygnus is visible with the unaided eye from a dark location but unrelated to the ancient supernova.
NASA has measured the rate of the Universe’s accelerating expansion via ground-based telescopes studying relatively nearby supernova explosions.
The mystery escalated in 1998 when Hubble Space Telescope observations of more distant supernovae proved the universe actually expanded more slowly in the past than it does today.
The expansion of the universe is not slowing down due to gravity, as everyone thought – it is actually speeding up.
Although astronomers remain unsure exactly what is causing the accelerating expansion, it has been given a name — dark energy.
This mysterious pressure remained undiscovered for so long because it is so weak that gravity overpowers it on the scale of humans, planets and even the galaxy.
Dark energy is pervasively present, but gravity constantly counteracts it.
It is only on an intergalactic scale that dark energy becomes noticeable, acting like a sort of weak opposition to gravity.