For most observers in the United States at this time of the year, the Rosette Nebula rises in the east at sunset and crosses high in the southern sky, then sets in the west at sunrise. It’s an enormous cloud of primarily hydrogen gas trailing behind the constellation Orion. It’s believed to be over 750 trillion miles or 130 light years across. It appears bigger to us than the more familiar Orion Nebula in spite of it being almost 4 times farther away at 5,200 light years.
Since it’s so large, it can easily fill the field of view of a medium-power eyepiece, but it can be hard to see since it’s a dim nebula compared to some others. This photo of a little less than half the nebula’s area has over six hours of exposure time so it’s bright enough to see lots of detail and structure.
There is a star cluster in the center of this nebula called NGC 2244. In this photo, nearly half of the cluster is visible at the top center. It contains some stars that are of the hottest and brightest type of star in the universe, called O-type stars. A typical surface temperature of these stars is believed to be about 90,000° F (50,000° C). Some of the hot blue stars in NGC 2244 are shining at the brightness of around 400,000 suns!
The dark clumps below the star cluster are called Bok globules and are dense clumps of gases and some dust. Bok globules can be found in other nebulae too, but there are quite a few in this area of the Rosette. They can contain the amount of material that would be included in as many as fifty suns. This dense matter shields the hot and brilliant radiation from nearby stars, causing the interior of the Bok globules to be some of the coldest parts of the universe. So, here in one photo, you can see a range of some of the hottest stars in the universe down to some of the coldest areas in the universe, about -450° F (-270° C).
The term Bok globules sounds interesting, but the globules’ name has no connection to describing their nature. The interesting connection is to their discoverer’s name–Bart Bok. He was the first to study and describe them in detail in the 1940s.
God’s greatness is seen in this photo just like in all others from space. The width of our solar system, including all eight planets and Pluto, is about 1/20 the size of each pixel on this photo. That means the tiniest detail you see in the picture could have 20 of our solar systems stretched across it. It’s big enough to be bewildering for even Bart Bok’s brain.
