Our galaxy, the Milky Way, is destined to “merge” with our giant neighbour, Andromeda, in about five billion years.
Currently both galaxies are approaching each other at speeds of 120 kilometres (km) per second, and “Milkomeda” is one name that has been dubbed for the combined entity.
Before the collision occurs though both galaxies will fly past each other twice, occurrences that could possibly result in the Sun, and its family of planets, being drawn into the Andromeda system.
There is also a remote 3% chance that the Sun will jump ship and defect to the Andromeda galaxy during the second close passage. “In the night sky, we would then see the Milky Way from a distance,” says Loeb.
Just to put the distances into some perspective, moving at a rate of 120 km per second means covering about 3.8 billion km per year. The planet Neptune is some 4.46 billion km from the Sun, so we are talking about some very, very, vast amounts of space here.
Originally published Thursday 28 January 2009.
If search engine queries here are anything to go by, the prospect of Antares, a red giant star located in the constellation of Scorpius, exploding seems to intrigue some visitors, so I decided to learn more about the imminent (anytime in the next million years, that is) Antares supernova.
In a word though, it will be spectacular.
While it will be unmissable in the night sky, the remnants of Antares may – for a short time – be visible during the day, and even alien astronomers in distant galaxies will temporarily see our galaxy, The Milky Way, outshine many other galaxies that are visible to them, as a result of the explosion.
Despite the galactic light-show the explosion of Antares will not however pose any direct danger to Earth.
There are fears that an exploding star, or supernova, could threaten our planet by way of debris from the blast, or that the resulting radiation and gamma rays could destroy Earth’s ozone layer, in turn triggering a mass extinction.
It has been found however that a supernova needs to be within 26 light years of Earth to cause any sort of harm, and Antares is some 600 light years away.
The only possible risk lies in the glare that any supernova could generate, which may be blinding, according to Dr Nick Lomb of the Sydney Observatory.
Antares isn’t the only potential supernova-star in the stellar neighbourhood either, and Eta Carinae, about 8000 light years away from Earth, could also explode at any time.
Originally published Tuesday 13 January 2009.
