Naturespeak 

The Milky Way and Other Great Galaxies

by John Nemy, Pacific Observatory

Far beyond the Milky Way lies the realm of galaxies, island universes like our own.

It was not until 1925 that humankind realized we reside in a galaxy. Even after 77 years it is hard to comprehend the concept of being galactic residents. When you look up at a star-filled sky it is difficult to have a sense of location.

It was the American astronomer Edwin Hubble who unravelled the mystery.

When Galileo first pointed his small telescope skyward in 1609 he was astonished to see a view full of stars not visible to the naked eye. Amongst his many other visual discoveries were strange out-of-focus stars resembling smudges of light. They were named "nebula," which is the Latin for "cloud". Astronomer thought these nebula(s) were part of one large system of celestial objects that the Earth and Sun belong to.

The question of what nebula were continually attracted the eye of astronomers for the next 300 years. As telescopes improved in the 1800's, some nebulae were resolved into large clouds with stars embedded in them. We know these regions today as stellar nurseries, the very place where new suns evolve from massive clouds of hydrogen gas and dust. The make up of spiral- and elliptic-shaped nebulae remained a mystery.

If a single person can be called central to the complex story of how human beings came to understand that we live within a galaxy and that a myriad of other galaxies surround us, that person is Edwin Powell Hubble.

In 1920 the keen young astronomer arrived at Mt. Wilson, California at the same time the new 100 inch Hooker telescope became operational. Hubble pointed the world's largest telescope of the time at the spiral nebula in Andromeda where he discovered very faint stars in the faint cloud and proved for the first time that these smudges of light were galaxies too.

That’s when we realized that the Milky Way is just one of billions of other galaxies created when the Universe was made.

Today we stare in awe at photos such as the Hubble Deep Field where 3,000 galaxies fill a single frame. The image covers the same amount of sky as a pin head held at arms distance.

We can only wonder what Hubble would have thought of the image and the name of the Space Telescope.

Today’s column is based on John Nemy’s upcoming talk, "The Milky Way and other Great Galaxies" (see below for time and location). The talk covers a lot of sky, from the Mount Wilson Observatory, California to the Hubble Space Telescope’s galactic journey. John's presentation follows humanity’s quest to understand the spiral nebulae.

Images from Star Hill, New Mexico, Torrance Barrens Dark Sky Reserve, Ontario, Manning Park and Mount Kobau, British Columbia will illustrate the talk.

Website of the Week : Follow John Nemy’s star search at www.nemy.com

Upcoming Events :

Friday, October 25th, 7:30 p.m. — The Milky Way and Other Galaxies

The first of several presentations by John Nemy of the Pacific Observatory at Millennium Place. The Whistler Naturalists are pleased to host John Nemy who is famed for his astronomy nights in past years at the Rendezvous on Blackcomb. John’s talk is suitable for all ages and includes amazing images and even more amazing commentary. Admission is by donation.

Sightings: NatureSpeak is prepared by the Whistler Naturalists. To report noteworthy bird sightings any time of year, please contact Michael Thompson (932-5010; email: redpath@telus.net).

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