Starship Asterisk*

Exploring the Antennae

Explanation: Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. Stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm that lasts for hundreds of millions of years. But the galaxies' large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning over 500 thousand light-years, this stunning view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkable mosaicked image was constructed using data from the ground-based Subaru telescope to bring out large-scale and faint tidal streams, and Hubble Space Telescope data of extreme detail in the bright cores. The suggestive visual appearance of the extended arcing structures gives the galaxy pair its popular name - The Antennae.

<< Previous APOD

This Day in APOD

Next APOD >>

[/b]

Just above and slightly to the left of the collision there appears to be something similar. Is this an artifact or is it a similar object?

I can see something, like a whisker, in the region highlighted by a red circle in the following screenshot: https://s23.postimg.org/e750zierf/Screen1.jpg

Looking at the red channel, assembled but NOT yet cleaned, I can find it as well: https://s23.postimg.org/ujf2p8t2z/Screen2.jpg

I don't think it is an artifact, IMHO.

Thanks.
Cheers.

Roberto

Galaxy mergers are among my favorite images.It does look to be another merge above & to the left(not the red line).

Thanks for chiming in, Roberto!

My interest in the red "whisker" is limited, although, who knows, it might be something shed by the Cheshire cat.
The APOD is superb, and the colors are splendid and so revealing. Both galaxies are highly distorted, and to me, their disks look like a pair of spoons, attached to long, bent handles. Both have obvious, bright yellow nuclei, and both have long bluish tails. But there are very obvious differences, too.



















Let's consider the differences! NGC 4038, at right in the APOD, has a bright blue (and pink) border of brilliant clusters, making it look like a piece of jewelery. NGC 4039, on the other hand, is rather yellow and featureless, somewhat like a bread shovel. The two galaxy disks are different because of them, NGC 4038, is gas-rich and brilliantly starforming, whereas the other galaxy is gas-poor and full of old stars.

Where the two galaxies meet there is a humongous brown and pink train wreck-splash of galactic proportions. The brown splash is dark dust, and the pink stuff is brilliant hydrogen emission from new star formation.

Note that the tail that emanates from gas-rich NGC 4038 is very long and full of kinks of star formation. The tail that emanates from NGC 4039 is shorter and quite smooth.

Great image!

Ann

Don't they look to a bean too, isn't it ?? LoL

Such a powerful image...the caption states, "stars in the two galaxies,...very rarely collide..." Have colliding stars ever been observed?

Those antennae are really difficult visually, even with a big scope. I've tried several times with no luck. The main colliding galaxies are interesting though.

Catalina wrote:Such a powerful image...the caption states, "stars in the two galaxies,...very rarely collide..." Have colliding stars ever been observed?

Not unambiguously. We may have observed secondary effects to stellar collisions such as supernovas or transient bursts of radiation. And we've twice observed black holes colliding in the "light" of gravitational waves.

Every time colliding galaxies are shown, we are assured that star collisions must be very rare, and I'll accept that.
But as the blurb to this pic says, " the galaxies' large clouds of molecular gas and dust often do [collide], triggering furious episodes of star formation near the center of the cosmic wreckage."
Such energetic events must release radiation - would that be hazardous for any indigenous life in the Antennae?
John

JohnD wrote:Every time colliding galaxies are shown, we are assured that star collisions must be very rare, and I'll accept that.
But as the blurb to this pic says, " the galaxies' large clouds of molecular gas and dust often do [collide], triggering furious episodes of star formation near the center of the cosmic wreckage."
Such energetic events must release radiation - would that be hazardous for any indigenous life in the Antennae?

The combination of the inverse square law and the protection provided by planetary atmospheres, magnetic fields, and oceans makes the threat from such radiation very local. You don't have to be very many light years away from such a region before radiation ceases to be much of a concern. That said, if a planet suddenly (where that means millions of years) finds itself in a star forming region, that's probably not good. Also, while collisions are rare, near passes are not. If a dense region of stars from another galaxy passed near our solar system, a collision with the Sun is extremely unlikely. But the disruption of planetary orbits can be expected, which is probably just as deadly to life on Earth.

Makes you go, Mmmmmmmm!

I believe the Solar System is currently in a gap between the arms of the Milky Way, where gas and stars are more dense,and where those protections may be less effective, as well as local novae/supernovae are more likely. Bit sensational - https://www.newscientist.com/article/mg ... milky-way/
John

These topics are really mind-blowing!!

What a gorgeous photo! A real delight! We ourselves are in a pretty dilute region of our galaxy, fortunately for astronomers. What if we had been in a dense molecular cloud? But most around us is ionized, and we can see reasonably well into the depths of the universe. Thank you, whoever!

• Men in Black (1997)

Kay: [looking skywards] They're beautiful, aren't they?

Jay: What?

Kay: The stars.

Jay: K, you're frightening your partner...

Kay: I haven't been looking for a partner. I've been looking for a replacement. I've just been down the gullet of an interstellar cockroach. That's one of a hundred memories I don't want.

Two Galaxies in Shock...

"The Shock of Creation?"

:---[===] *

Catalina wrote:Such a powerful image...the caption states, "stars in the two galaxies,...very rarely collide..." Have colliding stars ever been observed?

Wikipedia wrote:
V838 Monocerotis (V838 Mon) is a red variable star in the constellation Monoceros about 20,000 light years (6 kpc) from the Sun.[5] The previously unknown star was observed in early 2002 experiencing a major outburst, and was possibly one of the largest known stars for a short period following the outburst. Originally believed to be a typical nova eruption, it was then realized to be something completely different. The reason for the outburst is still uncertain, but several conjectures have been put forward, including an eruption related to stellar death processes and a merger of a binary star or planets.

JohnD wrote:Every time colliding galaxies are shown, we are assured that star collisions must be very rare, and I'll accept that.
But as the blurb to this pic says, " the galaxies' large clouds of molecular gas and dust often do [collide], triggering furious episodes of star formation near the center of the cosmic wreckage."
Such energetic events must release radiation - would that be hazardous for any indigenous life in the Antennae?
John

Like Chris said, radiation is likely to do only local damage. But look at the distorted shapes of these two galaxies. Enormous tidal forces must be running through them. That can't be good for any life forms dependent on a stable orbit of their planet around their sun.

Ann

The 'Hubble' in the credit is a link to the HubbleSite. On that webpage there is a link to a 'Space Telescope Live. Look at what Hubble is seeing right now!' webpage https://spacetelescopelive.org/ that is stated to show what Hubble is looking at. I did not know of such a webpage and so I thought I would mention it in case anyone else was unaware and may like to know. It is very interesting, particularly if it really is in real-time or very closely so.

DavidLeodis wrote:The 'Hubble' in the credit is a link to the HubbleSite. On that webpage there is a link to a 'Space Telescope Live. Look at what Hubble is seeing right now!' webpage https://spacetelescopelive.org/ that is stated to show what Hubble is looking at. I did not know of such a webpage and so I thought I would mention it in case anyone else was unaware and may like to know. It is very interesting, particularly if it really is in real-time or very closely so.

But if you read a few lines down you see that the image shown is not a live image, it's just showing us what the 'scope is pointed toward at the present time.

BDanielMayfield wrote:

DavidLeodis wrote:The 'Hubble' in the credit is a link to the HubbleSite. On that webpage there is a link to a 'Space Telescope Live. Look at what Hubble is seeing right now!' webpage https://spacetelescopelive.org/ that is stated to show what Hubble is looking at. I did not know of such a webpage and so I thought I would mention it in case anyone else was unaware and may like to know. It is very interesting, particularly if it really is in real-time or very closely so.

But if you read a few lines down you see that the image shown is not a live image, it's just showing us what the 'scope is pointed toward at the present time.

Thanks for that rather curt pointing out that I was wrong to think it was a live view. The webpage heading does though seem to imply that the image being shown was live, which is why I posted about its presence.

DavidLeodis wrote:

BDanielMayfield wrote:

DavidLeodis wrote:The 'Hubble' in the credit is a link to the HubbleSite. On that webpage there is a link to a 'Space Telescope Live. Look at what Hubble is seeing right now!' webpage https://spacetelescopelive.org/ that is stated to show what Hubble is looking at. I did not know of such a webpage and so I thought I would mention it in case anyone else was unaware and may like to know. It is very interesting, particularly if it really is in real-time or very closely so.

But if you read a few lines down you see that the image shown is not a live image, it's just showing us what the 'scope is pointed toward at the present time.

Thanks for that rather curt pointing out that I was wrong to think it was a live view. The webpage heading does though seem to imply that the image being shown was live, which is why I posted about its presence.

I appreciate your post, and checked the link immediately. It doesn't matter too much to me if the page in question is exactly "live", as long as it is really "up to date".

Ann

DavidLeodis wrote:

BDanielMayfield wrote:

DavidLeodis wrote:The 'Hubble' in the credit is a link to the HubbleSite. On that webpage there is a link to a 'Space Telescope Live. Look at what Hubble is seeing right now!' webpage https://spacetelescopelive.org/ that is stated to show what Hubble is looking at. I did not know of such a webpage and so I thought I would mention it in case anyone else was unaware and may like to know. It is very interesting, particularly if it really is in real-time or very closely so.

But if you read a few lines down you see that the image shown is not a live image, it's just showing us what the 'scope is pointed toward at the present time.

Thanks for that rather curt pointing out that I was wrong to think it was a live view. The webpage heading does though seem to imply that the image being shown was live, which is why I posted about its presence.

I apologize for the terseness of my earlier comment David. I was in a hurry, sorry that it came off as rude.

Bruce

Sandgirl just posted this image in the Recent Submissions forum, which prompted me to go back to it and look at it again when it was the APOD.

It really is a beautiful, lovely image. Thanks to Roberto Columbari, the colors are splendid. Thanks to Hubble, the resolution is great.

Look at some of the amazing background galaxies. At far left, to the upper left of a bright yellow foreground star, is a cluster of yellow galaxies. One of these galaxies has a truly amazing two-pronged tail, almost like a great fish swimming the cosmic seas! Or even slightly like a classic 1950s rocketship! (Even though the rocketship smiley available here has a three-pronged rear end!)

And just below a white double star near the top of the picture is a beautiful pair of interacting galaxies. Unlike the Antennae, this pair is unevenly matched, with one galaxy being much bigger than the other one. Note how the smaller galaxy has grown two long tidal tails, both of them reaching out for the larger galaxy.

Again, this APOD is a lovely image!

Ann