NGC 891: Awesome Edge-On Spiral Galaxy that's Cold-Shouldering Us

NGC 891 is a mysterious and enticing galaxy, showing us only its coin's edge. I am intrigued, but a coin's edge is not a sufficing profile. You never know a coin by its edge -- nor, as they say, a book by its cover. NGC 891 is cold-shouldering us, making us want even more earnestly to discover its unrevealed secrets. We will probably never ever be able to really do so. That is, in effect, be able to 'toss' NGC891 or ourselves instead so as to see either of its broad sides -- its head or tail. Unless, of course, we invent real time-travel, or develop technologies that achieve speeds at zillion multiples of that of light. 

Someone will try, but Nature's speed limits appear right now to stand emphatically in the way. The distances associated with this alluring heavenly massif, this farthing, seem just too forbidding for any human attempt to reach and get to really know it. Adam Block points out that NGC 891 is approximately 30 million light-years away from planet earth, in the Andromeda Constellation. Edgewise, it stretches like a zip for about 100 thousand light-years. That is, it would take 100,000 years for light to travel from NGC 891's extreme end on the left to the other end on the right-hand side -- or vice-versa. 

A succession of scientists, from Danish astronomer Olaus Roemer's seminal measurements in 1676 (he arrived at a speed of light of 214,000 kilometers per second) to the present have settled on a light speed of 299,792.458 km/s (see Gibbs (1997). Matt Williams (2016) has more recently translated this speed into 1.08 billion kilometers per hour, or 671 million mph (miles per hour). 

So you can imagine how many generations of humans it would realistically take to travel (at light speed) from just the lower-left end of NGC 891 'flatcoin' to the upper right, or vice-versa, in the image below. That is before you calculate the number of generations -- and the quantum of logistics -- that would be required to reach (at the same speed) the nearer end of that galaxy. And that is after you answer the question: Why bother?

Here is a NASA image of NGC 891 -- some 30 million light years away, as already noted:

READ: W.D. Ferris' earlier take on Galaxy NGC 891