APOD: Milky Way Rising (2023 Dec 01)

[APOD Robot]

Milky Way Rising

Explanation: The core of the Milky Way is rising beyond the Chilean mountain-top La Silla Observatory in this deep night skyscape. Seen toward the constellation Sagittarius, our home galaxy's center is flanked on the left, by the European Southern Observatory's New Technology Telescope which pioneered the use of active optics to accurately control the shape of large telescope mirrors. To the right stands the ESO 3.6-meter Telescope, home of the exoplanet hunting HARPS and NIRPS spectrographs. Between them, the galaxy's central bulge is filled with obscuring clouds of interstellar dust, bright stars, clusters, and nebulae. Prominent reddish hydrogen emission from the star-forming Lagoon Nebula, M8, is near center. The Trifid Nebula, M20, combines blue light of a dusty reflection nebula with reddish emission just left of the cosmic Lagoon. Both are popular stops on telescopic tours of the galactic center. The composited image is a stack of separate exposures for ground and sky made in April 2023, all captured consecutively with the same framing and camera equipment.

<< Previous APOD

This Day in APOD

Next APOD >>

[RocketRon]

Starry starry night ...

[Ann]

Milky Way rising. Image Credit & Copyright: José Rodrigues

What I find most interesting about this APOD is the gray color of the main dust lane of the Milky Way. The color is due to a magnificent sprinkling of stars in front of the dark dust lane. Many of these stars may be just foreground stars, unrelated to the dust lane, but it seems very likely that many of these stars were actually born here. Then again, what do we mean by "here"? The major dust lane of the Milky Way is thousands of light-years deep. Or rather, the major Milky Way dust lane that we see in projection is likely made up of large numbers of overlapping segments.

NGC 4535. Credit: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team

---

Beautiful barred spiral galaxy NGC 4535 has two major spiral arms, but also armlets and various dust structures located between the major arms. So if we see stars that appear to have formed in the dust lane of an edge-on galaxy, in which of the dust (and gas) structures were they actually born? Naturally, we can't see very deep into the Milky Way at all, because of the heavy dust extinction, so I find it likely that the dust lane we can see should have played a role in creating the stars that we see in front of it.

An old picture of edge-on spiral galaxy NGC 891 really demonstrates how parts of a galaxy's major dust lane may be sparkling with new stars, while an equally large part of it may seem all "dark and dead":

NGC 891. Credit: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT

---

Note that the "left half" of the central dust lane of NGC 891 is blue with recent star formation, whereas the "right side" is mostly "dark and dead". (Or it may just possibly be "pregnant" with a lot of unborn stars, but if so, we can't see it in Jean-Charles Cuillandre's picture.)

Let's look at the Milky Way from another angle (so to speak):

The northern Milky Way from Cygnus to Sagittarius. The very dark long dust lane in the image is called the Great Rift. There are no signs of obvious star formation in the Great Rift. Credit: Akira Fuji

---

The region of the Milky Way that we saw in the APOD was about this part of Akira Fuji's picture:

A small part of the Milky Way Akira Fuji.png (144.02 KiB) Viewed 2937 times

It is starry! And it's likely that this small part of the Milky Way dust lane really has given birth to a lot of stars.

Ann

[beryllium732]

APOD 1 December 2023 annotated.png

Milky Way rising. Image Credit & Copyright: José Rodrigues

What I find most interesting about this APOD is the gray color of the main dust lane of the Milky Way. The color is due to a magnificent sprinkling of stars in front of the dark dust lane. Many of these stars may be just foreground stars, unrelated to the dust lane, but it seems very likely that many of these stars were actually born here. Then again, what do we mean by "here"? The major dust lane of the Milky Way is thousands of light-years deep. Or rather, the major Milky Way dust lane that we see in projection is likely made up of large numbers of overlapping segments.

NGC 4535. Credit: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team

---

Beautiful barred spiral galaxy NGC 4535 has two major spiral arms, but also armlets and various dust structures located between the major arms. So if we see stars that appear to have formed in the dust lane of an edge-on galaxy, in which of the dust (and gas) structures were they actually born? Naturally, we can't see very deep into the Milky Way at all, because of the heavy dust extinction, so I find it likely that the dust lane we can see should have played a role in creating the stars that we see in front of it.

An old picture of edge-on spiral galaxy NGC 891 really demonstrates how parts of a galaxy's major dust lane may be sparkling with new stars, while an equally large part of it may seem all "dark and dead":

NGC 891. Credit: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT

---

Note that the "left half" of the central dust lane of NGC 891 is blue with recent star formation, whereas the "right side" is mostly "dark and dead". (Or it may just possibly be "pregnant" with a lot of unborn stars, but if so, we can't see it in Jean-Charles Cuillandre's picture.)

Let's look at the Milky Way from another angle (so to speak):

The northern Milky Way from Cygnus to Sagittarius. The very dark long dust lane in the image is called the Great Rift. There are no signs of obvious star formation in the Great Rift. Credit: Akira Fuji

---

The region of the Milky Way that we saw in the APOD was about this part of Akira Fuji's picture:


A small part of the Milky Way Akira Fuji.png


It is starry! And it's likely that this small part of the Milky Way dust lane really has given birth to a lot of stars.

Ann

If one be in outer space just outside earth in a spacesuit would the surrounding looks exactly the same as in the picture? Or is it just a long exposure that makes everything so detailed?

[Chris Peterson]

If one be in outer space just outside earth in a spacesuit would the surrounding looks exactly the same as in the picture? Or is it just a long exposure that makes everything so detailed?

The atmosphere only makes a tiny difference in what the sky looks like. Being in space would make only a tiny visual difference. These objects are simply not bright enough to stimulate our color vision, nor bright enough for us to see much contrast. That requires collecting a lot more photons (which takes time) and careful processing.

[beryllium732]

If one be in outer space just outside earth in a spacesuit would the surrounding looks exactly the same as in the picture? Or is it just a long exposure that makes everything so detailed?

The atmosphere only makes a tiny difference in what the sky looks like. Being in space would make only a tiny visual difference. These objects are simply not bright enough to stimulate our color vision, nor bright enough for us to see much contrast. That requires collecting a lot more photons (which takes time) and careful processing.

So we don't see anything resembling what is shown in this picture? I see!