Arches in space make heads turn

The Andromeda galaxy, also known as cosmic object M31, is on a collision course with our own galaxy. However, it is still two and a half million light-years away and can be seen with the naked eye as a faint speck of light on a clear starry night, far from light pollution.

A huge nebula

However, an international team of amateur astronomers may have detected the first harbinger of this collision: a turquoise arc in the region of the Andromeda galaxy. It has a relatively huge range of about three full moons lined up next to each other.

Bending has now been demonstrated many times over

However, the very faint haze arc was only detected when amateurs combined exposures for a total of 111 hours on a computer and focused on very narrow light spectra. Meanwhile, the arch can also be spotted by other photographers from other places with different technical equipment. This excludes that the phenomenon is caused by a technical or optical error.

Many theories do not apply here

Innsbruck astrophysicist Stefan Kimmiswinger and colleagues attribute the turquoise color to oxygen, which has a double positive charge. However, in such cases, the hydrogen red light must also be detectable. This is missing in this case, and so many of the classic explanations for such nebulae are discarded.

The idea of ​​speculation provides a possible explanation

Therefore, professional astronomers do not exclude that this is really the first effect of a future collision with our galaxy, because the galaxies are also surrounded by some kind of atmosphere, which is very thin and stretches far into space. However, this is just a speculative idea. It will be several billion years before the Andromeda Galaxy collides with our Milky Way.