APOD: Supernova Remnant Puppis A (2014 Sep 12)

[Nitpicker]

how far does " nearby " have to be to not be " nearby " anymore ?

Well, that depends.

Since the approximate radius of the Milky Way is about 50,000 light-years, a supernova 7,000 light-years away is pretty nearby.

Ann

I thought the radius of the Milky Way was approximately 100,000 light years?

I suppose it depends on where you define the edge to be, but Wikipedia says a radius of 50,000 to 60,000 light years.

[rstevenson]

I thought the radius of the Milky Way was approximately 100,000 light years?

The diameter of the Milky Way is about 100,000 to 120,000 ly.

Rob

[jsmunroe]

how far does " nearby " have to be to not be " nearby " anymore ?

Well, that depends.

Since the approximate radius of the Milky Way is about 50,000 light-years, a supernova 7,000 light-years away is pretty nearby.

Ann

I thought the radius of the Milky Way was approximately 100,000 light years?

Nope. diameter is 100k. Radius is 50k.

[bystander]

I thought the radius of the Milky Way was approximately 100,000 light years?

The Milky Way is a barred spiral galaxy some 100,000–120,000 light-years in diameter, which contains 100–400 billion stars.

That would be 50-60 thousand light-years in radius.

[starsurfer]

Oh I must have got the two mixed up!

[bystander]

I admit, you had me confused. I had to go look to make sure.