Exomoons

wexie

Folks,

I was just reading the article below and was wondering if someone could explain the significance of this?

If I read the article correctly (and I'm quite happy to admit that may not be the case) an exomoon is a moon that orbits a planet that orbits a star other than our sun?

So just a moon outside of our own solar system? Really no different than our own moon other than that it's not in our own solar system?

Aren't there likely to be lots and lots and lots of those?

https://www.bbc.com/news/science-environment-45707309

Thanks for explaining

mikhail

Not an expert, but my guess is that this is an extension of the hunt for exoplanets - planets around other suns. That whole field has exploded in the past few decades. The first one was found around 1990 or so, and now they know of many thousands - the article says 3500 or so.

A planet is very faint, and from so far away it's tough to see them relatively close their parent star; presumably it's even harder to resolve a planet-moon system into separate parts. And to be clear, mostly we're not really 'seeing' them, but detecting their presence via some signal such as the doppler shifts on a star's spectrum. Most of the tricks they use to do this work better for bigger planets, so to extend it as far as to find a moon is a milestone in the science of exoplanet detection.

Explanet detection is interesting because (a) we had no idea really how many planets were around a typical star, (b) having data about multiple solar systems helps test models of how solar systems evolve, and (c) the public are far more excited by relative easily explained discoveries like this than by some exotic new pulsar or stellar jet formation.

wexie

mikhail wrote: »

A planet is very faint, and from so far away it's tough to see them relatively close their parent star; presumably it's even harder to resolve a planet-moon system into separate parts. And to be clear, mostly we're not really 'seeing' them, but detecting their presence via some signal such as the doppler shifts on a star's spectrum. Most of the tricks they use to do this work better for bigger planets, so to extend it as far as to find a moon is a milestone in the science of exoplanet detection.

Thanks for that, so if I understand it then the excitement isn't so much over having found an exomoon but over having found an exomoon (ie. actually having been able to detect one)?

mikhail

Yep.

Avatar MIA

wexie wrote: »

Thanks for that, so if I understand it then the excitement isn't so much over having found an exomoon but over having found an exomoon (ie. actually having been able to detect one)?

Although, the exomoon in this instance is Neptune sized. But, it's the best explanation for the data they have seen. They even disregarded the possibility of a spaceship

JupiterKid

Exomoons as described here are moons of exoplanets - that is, planets orbiting stars other than our sun. The fact that they can be detected at all by astronomers is pretty amazing.

riffmongous

I mean if you think about it we sort of take moons for granted but our own solar system is actually a pretty small sample set with a lot of variation and the more complete info we get about other solar systems the better