Sky and Telescope - March 2018 - 43

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WHEN TO
USE THE MAP

Late Jan
Midnight
Early Feb 11 p.m.
Late Feb
10 p.m.
Early Mar 9 p.m.
Late Mar
9 p.m.*
*Daylight-saving time

I

admit up front that the lenticular galaxy NGC 2768
isn't an obvious choice for a binocular highlight.
It's stashed away in the western reaches of the Great
Bear, about 1.5° south of 16 Ursae Majoris. If you've
roamed out that way, chances are you're a galactophile, or you're working through the Herschel 400, or
both. Just under 10th magnitude, the galaxy's barelymore-than-stellar glow is also not terribly bright (you
may be thinking the same thing about me right now).
So what's the story - what does NGC 2768 have
to offer? The galaxy does have one felicitous property: It lies 65 million light-years away. Or at least
it did when the light that we see now left it. Within
the confidence bands allowed by terrestrial dating
and astronomical measurements, that's right about
the time that a big hunk of rock from space plowed
into the Yucatan Peninsula, threw up enough dust to
crash the biosphere, and precipitated the extinction
of all the dinosaurs that weren't already birds. We
mammals had spent the previous 160 million years
- the first two-thirds of our time on Earth - living in
trees and holes and never, ever getting bigger than
a modern badger. Without that impact, you and I
would probably still be tree shrews.
NGC 2768 doesn't have any direct connection to
the dinosaur-killer, other than its light being the same
age just now, "now" being the point in cosmic history
when we, the beneficiaries of the impact, have gained
the intelligence and built the tools - handheld tools,
even, the reason for this column - to look back 65
million light-years, to maybe the most important turning point in our history. As a paleontologist-astronomer, I may be biased, but I think that's worth a look.

¢ MATT WEDEL enjoys crossing the streams of his
professional and amateur careers, and he has not
triggered any catastrophes so far.
sk yandtelescope.com * M A RCH 2 018

43
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Sky and Telescope - March 2018

Table of Contents for the Digital Edition of Sky and Telescope - March 2018
