Starship Asterisk*

The Orion Nebula in Infrared from WISE

Explanation: The Great Nebula in Orion is an intriguing place. Visible to the unaided eye, it appears as a small fuzzy patch in the constellation of Orion. But this image, an illusory-color four-panel mosaic taken in different bands of infrared light with the Earth orbiting WISE observatory, shows the Orion Nebula to be a bustling neighborhood of recently formed stars, hot gas, and dark dust. The power behind much of the Orion Nebula (M42) is the stars of the Trapezium star cluster, seen near the center of the featured image. The orange glow surrounding the bright stars pictured here is their own starlight reflected by intricate dust filaments that cover much of the region. The current Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years.

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Today's APOD appears to be a repeat from January 19, 2015, although today's version is a closeup of the picture from 2015. I don't mind that this is a repeat, because it is a fascinating image.


Infrared imagery can really reveal fascinating information on starforming nebulas. So here are two versions of another infrared picture of the Orion Nebula, this time from Spitzer:









































The picture at left shows a comparison between the Orion Nebula in infrared light and the Orion Nebula in visible light. Perhaps the most interesting aspect is the dusty ridge stretching between M43 (the small round red nebula "above" M42) and The Running Man Nebula (at top). A lot of stars have formed along this ridge, but they can't be seen in optical light.

The picture at right shows a closeup of young stars and star formation along the dusty ridge, and it also shows a closeup of the Trapezium region in infrared.

One aspect that I find confusing in today's APOD is the pitch black feature that can be seen close to the center of the image, adjacent to the roundish object that is M43. A dark feature can actually be seen right next to M43 both in Spitzer's infrared image and in Adam Block's visible image.

What can that dark thing be? Maybe a hole in the nebula?

Ann

Wow we are lucky to be living in this time period. I was 10 years old when Neil Armstrong landed on the Moon. Then we get all these pictures of the planets including Pluto and maybe I will live to see man land on Mars. Pity the people living 100,000 years from now. The Orion and Horsehead nebula will evaporate. Just last week a report said the rings of Saturn will rain down on Saturn and disappear in 100,000 years. The Big Dipper or Plough will flatten out in 100,000 years. The Moon is moving away from Earth and in 100,000 years there will no more be total eclipses of the sun. Betelgeuse will likely have exploded in 100,000 years. I wonder what else will no longer be around for our descendants?

Would the Pleiades have been in this type of context 100,000 years ago or earlier?

Ann wrote: ↑Wed Jan 02, 2019 8:09 am
One aspect that I find confusing in today's APOD is the pitch black feature that can be seen close to the center of the image, adjacent to the roundish object that is M43. A dark feature can actually be seen right next to M43 both in Spitzer's infrared image and in Adam Block's visible image.

What can that dark thing be? Maybe a hole in the nebula?

• Yes...a hole in the nebula through which one can observe a double star.

De58te wrote: ↑Wed Jan 02, 2019 10:10 am ... Just last week a report said the rings of Saturn will rain down on Saturn and disappear in 100,000 years. ... The Moon is moving away from Earth and in 100,000 years there will no more be total eclipses of the sun. ...

I think you (or that reporter) missed a few zeros. Saturn's rings may be gone in about 100 million years. As for the Moon, it will be almost 4 km further away in 100,000 years*, so near total eclipses will be even more spectacular, being of the ring variety.

Rob

* that's based on this online article that says "The Moon's orbit ... is indeed getting larger, at a rate of about 3.8 centimeters per year."

rstevenson wrote: ↑Wed Jan 02, 2019 5:55 pm

De58te wrote: ↑Wed Jan 02, 2019 10:10 am ... Just last week a report said the rings of Saturn will rain down on Saturn and disappear in 100,000 years. ... The Moon is moving away from Earth and in 100,000 years there will no more be total eclipses of the sun. ...

I think you (or that reporter) missed a few zeros. Saturn's rings may be gone in about 100 million years. As for the Moon, it will be almost 4 km further away in 100,000 years*, so near total eclipses will be even more spectacular, being of the ring variety.

Rob

* that's based on this online article that says "The Moon's orbit ... is indeed getting larger, at a rate of about 3.8 centimeters per year."

Keep in mind that the Moon's orbit doesn't have an eccentricity of zero. Over a month, its distance from the Earth varies by about 43,000 km. The nature of an eclipse depends upon where the Moon is in its orbit. It will be a long, long time before its slowly increasing distance has more effect than its current eccentricity.