Starship Asterisk*

Chris Peterson wrote:

DavidLeodis wrote:One personal gripe (apart from the colours of the processed image) is that as I like to use links in the explanation to APODs I did find the 27 links in the explanation to this APOD were far too many, such that I gave up on using many of them. There has been a tendency for quite some time now to increase the number of links to further information (which must take time in the production of an APOD) but I wonder just how many ever get used?

I scan my mouse over the links and check where they go before clicking. I can usually tell if it's something I want to follow.

In any case, it's easier not to click on a link than it is to follow a link not present. Better too many than too few.

As my father, who grew up poor in rural Portugal during the depression, would say, "it's better to have it and not need it than to need it and not have it."

From the description:

"Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun."

The above sentence is missing the word 'currently' between "is" and "located". The orbital velocity of our solar system around the Milky Way is independent of anything (and everything) else in the galaxy, including the current arm we're sailing through. Look at extinction charts for Earth and you'll notice regular minor and major events. About every 65MY we drift through another busier part (i.e. "arm") of the galaxy, the last time was ~65MY ago.

JeffGee wrote:From the description:

"Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun."

The above sentence is missing the word 'currently' between "is" and "located". The orbital velocity of our solar system around the Milky Way is independent of anything (and everything) else in the galaxy, including the current arm we're sailing through. Look at extinction charts for Earth and you'll notice regular minor and major events. About every 65MY we drift through another busier part (i.e. "arm") of the galaxy, the last time was ~65MY ago.

This sort of information is not known with enough certainty to be included in an APOD.

JeffGee wrote:From the description:

"Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun."

The above sentence is missing the word 'currently' between "is" and "located".

Not really relevant, because regions like the Orion Nebula are very short lived. From its beginning to its end, there won't be a major shift in the relative position between us and it (especially as it's moving in a similar galactic orbit to us).

The orbital velocity of our solar system around the Milky Way is independent of anything (and everything) else in the galaxy, including the current arm we're sailing through.

Independent in a sense. However, everything in our region of the galaxy is in a fairly similar orbit.

Look at extinction charts for Earth and you'll notice regular minor and major events. About every 65MY we drift through another busier part (i.e. "arm") of the galaxy, the last time was ~65MY ago.

Theories based on this idea are poorly supported by evidence.