Al Stahler: The winter night sky | TheUnion.com

Al Stahler: The winter night sky

Al Stahler
Columnist

One question has always dominated astronomy: “What the heck IS that thing?”

“That thing” might be something never before seen or something — some force, some form of energy — that makes familiar objects behave oddly. But WHAT? The mystery might take years or centuries to resolve.

Some of these mystery objects are visible to the naked eye.

If you’ve got a good view to the east at sunset or, a few hours later, higher up, the premier constellation of winter – Orion, the hunter – is easy to recognize by the line of three stars that compose his belt. And hanging from the hunter’s belt is his dagger, also composed of three stars.

Looking into the Orion nebula, we’re looking into what our sun’s nursery must have looked like, four-and-a-half billion years ago.

Looking at the middle star of the dagger in binoculars reveals it to be a fuzzball – a nebula (Latin for “cloud”). A small telescope reveals the Orion nebula to be a glowing cloud of gas and dust, and, embedded within, sharp, pinpoint stars: BABY stars.

The Orion fuzzball – the Orion nebula – is a womb, within which baby stars are born.

Looking into the Orion nebula, we’re looking into what our sun’s nursery must have looked like, four-and-a-half billion years ago. Some astronomers have taken up the challenge of looking for our sun’s sibs – sibling stars of the same age, with the same mix of atoms, as our sun: born at the same time, within the same cloud of gas and dust.

Another fuzzball hangs high in the winter sky, and no telescope is necessary to see its fuzziness. But you’ve got to know just where to look, and you might have to employ a special way of looking.

Our eyes have evolved to see most clearly – and in living color – in the central part of our view. But evolution is always a compromise, and our sharp, color-sensing cells are not super-sensitive to light – they don’t see well in the dark. Fortunately, evolution has surrounded these central cells with a ring of color-blind but super-sensitive cells … the cells we rely on when rummaging about in the dark, hoping for a glimpse of grey. We use them best when we look out of the corner of our eye (“averted vision”).

In the late 1800s and early 1900s, astronomers detected stars in the Andromeda Nebula, but they couldn’t decide whether the nebula was a collection of stars within our own Milky Way galaxy (implying that our galaxy is all there is to the universe). Or could it be outside our own (making the universe a LOT larger)?

Finally, in the 1920s, Edwin Hubble measured the distance to the Andromeda nebula, and found it WAY outside our own. Modern measurements put the Andromeda Galaxy two-and-a-half million light years from the Milky Way.

That’s 15 million million million miles … making it the furthest thing we can see with the naked eye.

And it’s coming our way … at a quarter-million miles an hour. Fortunately, even at that rate, it’ll take billions of years for the Andromeda Galaxy to cross two-and-a-half million light years.

This Saturday night, local astronomers will set up scopes at the junction of the old Downieville Highway and State Route 49, beginning at 7 p.m. The public is welcome – it’s free – bring the kids and dress warm.

Al Stahler enjoys sharing nature with friends and neighbors.  His science and nature programs may be heard on KVMR (89.5 FM), and he may be reached stahler@kvmr.org.


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