Astronomy/Galaxy blind spot?

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Expert: - 3/31/2008


Question
Hi Tom

I’m sure I must be missing something. Last night I was coming to grips with a star chart on my computer and the amount of stuff there is besides the messier objects. In particular I was looking at the amount of NGC galaxies there are, when I noticed a relatively empty strip that runs across. To me this strip looks like there must be a blind spot due to the material in the milky way. Have I interpreted this correctly? And if I have, could this blind spot hide anything, like a closer galaxy than Andromeda for instance?

Thanks. David.


Answer
Hi David,
Yes, the dust and gas lanes in our Galaxy provide an effective
block in visible light for distant galaxies (but there are
an awful lot of NGC planetary nebulae embedded in the Milky Way
plane, as that is just the common evolution from the Red Giant to White Dwarf route).  So there is certainly no lack of NGC numbers in the Milky Way plane, (lots of NGC open star clusters too)... just galaxies, and perhaps a few globular star clusters hidden from us.

Yes, it probably does hide some Deep Sky objects from us in visible
light, just like the Andromeda Galaxy itself (3 degrees across)
probably hides some more distant galaxies from us too.  Not much
we can do about it though, in visible light.

Well, Andromeda is not the closest galaxy...the 2 Magellanic
Clouds, our companion galaxies are closer (~160,000 ly), as are the  dwarf galaxies currently being cannabilized by the Milky Way,
and I believe there are a few other small dwarf galaxies that are closer than M-31. But yes, it is possible, but not likely of that size, because non-visible light scopes ( Radio, Infrared, UV, X-ray, etc) can penetrate the dust and gas and I would think if anything of
any size, comparable to M-31 existed, we would have already discovered it. (Also, that's how we have to 'view' the center of our own Galaxy which is also blocked, by using Radio and Infrared Scopes).

Then again, perhaps not...so stay tuned for the James Webb Infrared
Space telescope to be launched in 2014.  There are always new
discoveries being found, in astronomy.

Clear Skies,
Tom Whiting
Erie PA

Astronomy

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Tom Whiting

Expertise

Astronomy has been my hobby/pasttime for over 50 years.  Currently own 3 telescopes, the largest of which is a 30 inch Newtonian truss Dob that is portable.I taught Astronomy/Meteorology at the University Level for 13 years before retiring in 1995. Being retired and home most of the time, I am able to answer all questions relatively quickly, unless it's a new moon weekend with good observing conditions.  No astrology questions please, or questions about alleged UFO picture identifications.

Experience

Experience: Astronomy has been my hobby and study for over 50 years. We currently now own a 30 inch portable telescope (Updated - Pennsylvania`s largest portable telescope). It can be seen on our website at:http://www.velocity.net/~bwhiting and also attend several regional starparties during the year, and have been on 5 total solar eclipse expeditions.

Organizations: President, Erie County Mobile Observers Group for over 15 years.

Publications: Wrote the "Over Erie Skies" newspaper article in our local newspaper for 11 years (1975-86).

Education: Masters Degree- Taught at the University level for 13 years. Retired 20 years -USAF Pilot - KC-135 with 180 combat missions;  Also Eagle Scout, Philmont staff 2 Yrs, Order of Arrow Lodge Chief, Ham Radio (inactive).

Awards: two discoveries: The mini-coathanger asterism in Ursa Minor (the little dipper) And the mini-ladle- another asterism in the bowl of Ursa Minor. Clients: Currently President of the ECMOG as mentioned above.

Education/Credentials
BS  Metallurgical Engineering Grove City College, PAMaster's Degree, Gannon University, Erie, PA Also retired USAF pilot, 20 years.

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