Unidentified flying objects and galactic fireworks

By Gary Zientara
Mount Sangre Observatory
Posted 6/27/19

Mount Sangre ObservatoryAlthough NGC 4565 looks like an unidentified flying object, it's far from being a flying saucer. In fact, this UFO was first identified as a nebula by William …

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Unidentified flying objects and galactic fireworks

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Although NGC 4565 looks like an unidentified flying object, it's far from being a flying saucer. In fact, this UFO was first identified as a nebula by William Herschel in 1785. Later, it was designated NGC 4565 in John Lewis Emil Dreyer's New General Catalogue compiled in 1888. So it's been "flying" in New Mexico's skies for a long time.

We know much more now about this "nebula" than when it was first discovered. Since 1908 when Edwin Hubble discovered that these nebulae were galaxies, we've found that NGC 4565 is very similar to our own Milky Way that we see spanning from horizon to horizon in our summertime night skies. We see a dim band of milky light that is thin from the northeast horizon to much thicker and brighter at the southwest horizon. Compare this to the band of light extending from the bulging center of NGC 4565 to one of its edges. Imagine that we propel our solar system out of the Milky Way toward NGC 4565 until its band of stars and central bulge look the same size in our night sky as the Milky Way does. We could then look back 30 million light years from which we came to see the Milky Way looking remarkably the same as NGC 4565.

Look at the smaller galaxy in the lower left corner of the image and you'll find what looks like a smaller version of NGC 4565. This is NGC 4562 and it looks smaller because it's 12 million light years farther away than NGC 4565. Now look at the dim fuzzy yellow-green dots that seem to extend from the upper left tip of the star band of NGC 4565. There are at least 12 of them. (Note: you'll probably need to view this in The Taos News online to get the highest resolution image.) These fuzzy dots are arranged in a kind of "J" string pattern and each is a distant galaxy at least 400 million light years away. So now, all you have to do to understand the 3D structure of our "local" universe is to look at our Milky Way on a clear summer night and use this image to see what it would look like as you travel farther and farther into deep space. Now, isn't that at least as interesting as a UFO?

Sparkling fireworks of M10

The universe is helping us celebrate the Fourth of July with this star cluster looking like a sparkling fireworks display. This is Messier 10 (M10), one of 110-plus globular star clusters drifting in random orbits forming a spherical pattern around the center of our Milky Way galaxy. This one is 14,300 light years away in the constellation Ophiuchus (OH-fee-YOU-kuss), the Serpent Bearer.

Globular star clusters are some of the oldest objects in our galaxy. Some astronomers think they formed before the Milky Way and that some globular clusters are the remnants of other galaxies that became gravitationally absorbed into our giant spiral galaxy. M10 is a swarm of tens of thousands of stars in a complex gravitational field. The individual star colors display their surface temperatures with the blue stars being the hottest. The estimated age of M10 is 11.39 billion years which makes this cluster almost three times older than our sun. This vast age has puzzled astronomers because hot blue stars should have long ago ended their lives as supernovas yet there are still quite a few in this cluster.

Blue stars in globular clusters are called "blue stragglers," implying that they formed later than they should have. But that doesn't jive with the general makeup of globular clusters that are practically devoid of interstellar gas and dust necessary to form new stars. However, there is evidence that these stars formed later from gravitational accretion (gradual buildup) of gas from one star in close orbit around another or from two stars merging into one as they collide. Given the dense glob of stars in clusters like this, both accretion and collisions are certainly possible especially near their cores where most of the blue stragglers are in M10.

Mount Sangre Observatory is in Angel Fire, New Mexico.

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