[InterceptPoint]

So I have to ask: how do you detect Iso-propyl cyanide from 27,000 light years away?

I can answer that:

You take a small sample and add some other chemical whose name I forget. If it turns purple then it's Iso-propyl cyanide. Simple. Although, it could be that it turns pink. Or blue. Or something like that. Don't ask how you get that sample. We didn't cover that in chemistry. And, lets face it. 27,000 light years is a long ways away.

[Revel]

And of course the cloud could have ceased its existence 27,001 Years ago. We wouldn’t find out until next year.