Starship Asterisk*

sherylbrock wrote: ↑Sun Oct 11, 2020 3:49 pm

Ann wrote: ↑Tue Jan 28, 2020 1:26 am

Chris Peterson wrote: ↑Tue Jan 28, 2020 12:38 am

C = πD. If it is 800,000 ly across (which I'm doubtful is accurate) its circumference is about 2.4 million ly. The formula you give is for area (although the meaning of area is a bit ambiguous for something which is shaped like a combination of a spheroid and a disc).

And that area would be 502 billion square ly, not trillion. (1 billion = 10⁹.)

Click to view full size image

Visible disk (220,000 ly) of Andromeda Galaxy, vs halo (2 million ly).
Credits: NASA/STScI. Full size here.

As Chris said, it seems improbable that the radius of UGC 2885 is 800,000 light-years across. But its true radius does not appear to be well known. NASA/ESA claimed that it is 2.5 times wider than the Milky Way (which would make it perhaps some 250,000 light-years across), whereas Wikipedia wrote that it is 463,000 light-years across.

But UGC 2885 might actually be at least 800,000 light-years across, if we take its halo intoappvalleyaccount. Being an isolated galaxy in space, it is sure to have a halo. Our neighbour Andromeda, which is not isolated in space, has a huge halo. See the picture.

On a different note, different sources disagree on how wide the visible disk of Andromeda is. According to Wikipedia, its diameter is 220,000 light-years, but according to NASA.gov, its halo is just 6 times wider than its visible disk, even though the illustration at right suggests that the halo is 2 million light-years across.

In any case, if we include the halo of UGC 2885 its diameter might well be 800,000 light-years.

Ann

Great info Ann. Thanks for sharing this...

Regards,
Sherryl

Ann wrote: ↑Tue Jan 28, 2020 1:26 am

Chris Peterson wrote: ↑Tue Jan 28, 2020 12:38 am

Guest wrote: ↑Tue Jan 28, 2020 12:28 am

C = r(squared) x pi

C = πD. If it is 800,000 ly across (which I'm doubtful is accurate) its circumference is about 2.4 million ly. The formula you give is for area (although the meaning of area is a bit ambiguous for something which is shaped like a combination of a spheroid and a disc).

And that area would be 502 billion square ly, not trillion. (1 billion = 10⁹.)

Click to view full size image

Visible disk (220,000 ly) of Andromeda Galaxy, vs halo (2 million ly).
Credits: NASA/STScI. Full size here.

As Chris said, it seems improbable that the radius of UGC 2885 is 800,000 light-years across. But its true radius does not appear to be well known. NASA/ESA claimed that it is 2.5 times wider than the Milky Way (which would make it perhaps some 250,000 light-years across), whereas Wikipedia wrote that it is 463,000 light-years across.

But UGC 2885 might actually be at least 800,000 light-years across, if we take its halo intoappvalleyaccount. Being an isolated galaxy in space, it is sure to have a halo. Our neighbour Andromeda, which is not isolated in space, has a huge halo. See the picture.

On a different note, different sources disagree on how wide the visible disk of Andromeda is. According to Wikipedia, its diameter is 220,000 light-years, but according to NASA.gov, its halo is just 6 times wider than its visible disk, even though the illustration at right suggests that the halo is 2 million light-years across.

In any case, if we include the halo of UGC 2885 its diameter might well be 800,000 light-years.

Ann

Chris Peterson wrote: ↑Tue Jan 28, 2020 12:38 am

Guest wrote: ↑Tue Jan 28, 2020 12:28 am

hollandinseattle wrote: ↑Tue Jan 28, 2020 12:27 am Has anybody done the math on this? If the the galaxy is 800,000 light years across, its circumference would be a staggering 502 TRILLION light years. Is this right or am I not carrying the one?

C = r(squared) x pi

C = πD. If it is 800,000 ly across (which I'm doubtful is accurate) its circumference is about 2.4 million ly. The formula you give is for area (although the meaning of area is a bit ambiguous for something which is shaped like a combination of a spheroid and a disc).

And that area would be 502 billion square ly, not trillion. (1 billion = 10⁹.)

Guest wrote: ↑Tue Jan 28, 2020 12:28 am

hollandinseattle wrote: ↑Tue Jan 28, 2020 12:27 am Has anybody done the math on this? If the the galaxy is 800,000 light years across, its circumference would be a staggering 502 TRILLION light years. Is this right or am I not carrying the one?

C = r(squared) x pi

hollandinseattle wrote: ↑Tue Jan 28, 2020 12:27 am Has anybody done the math on this? If the the galaxy is 800,000 light years across, its circumference would be a staggering 502 TRILLION light years. Is this right or am I not carrying the one?

neufer wrote: ↑Sun Jan 26, 2020 6:42 pm

Ann wrote: ↑Sun Jan 26, 2020 4:24 am

sillyworm 2 wrote: ↑Sat Jan 25, 2020 6:17 pm

Thanks starsurfer! In the top pic..what is the name of the galaxy at 8 o'clock?

Well, there is a galaxy at about 8 o'clock in the ESA/Digitized Sky Survey 2/Davide De Martin picture.
The galaxy is very tiny and faint. I could find something through my software at about that position, and if I'm right,
the galaxy is called UGC 2920. According to my software, it is a 15th magnitude object, so it is faint indeed.
The only picture I could find of it, apart from its tiny mark on the ESA/
Digitized Sky Survey 2/Davide De Martin picture, is this one.

"A couple of hours ago (~8 o'clock) a galaxy far, far away...."

Ann wrote: ↑Sun Jan 26, 2020 4:24 am

sillyworm 2 wrote: ↑Sat Jan 25, 2020 6:17 pm

Thanks starsurfer! In the top pic..what is the name of the galaxy at 8 o'clock?

Well, there is a galaxy at about 8 o'clock in the ESA/Digitized Sky Survey 2/Davide De Martin picture.
The galaxy is very tiny and faint. I could find something through my software at about that position, and if I'm right,
the galaxy is called UGC 2920. According to my software, it is a 15th magnitude object, so it is faint indeed.
The only picture I could find of it, apart from its tiny mark on the ESA/
Digitized Sky Survey 2/Davide De Martin picture, is this one.

sillyworm 2 wrote: ↑Sat Jan 25, 2020 6:17 pm Thanks starsurfer! In the top pic..what is the name of the galaxy at 8 o'clock?

starsurfer wrote: ↑Sat Jan 25, 2020 1:25 pm Try finding it in this widefield image by Rogelio Bernal Andreo.

starsurfer wrote: ↑Sat Jan 25, 2020 1:25 pm Try finding it in this widefield image by Rogelio Bernal Andreo.

Chris Peterson wrote: ↑Sat Jan 25, 2020 3:09 pm

BaldEagle wrote: ↑Sat Jan 25, 2020 2:42 pm
Today's APOD is Rubins Galaxy. At the center, it appears to whirlpool down toward its singularity. If seen from the underside would it appear to whirlpool down as well?

The whirlpool effect is an illusion. Nothing is moving inwards- everything is in fairly stable, near circular orbits, regardless of distance from the center. The appearance of thin and thick bands, or high and low bands, is also an illusion. This is a flat disc with a bulging center. The galaxy would look pretty much the same viewed from the other side, except for the direction the arms point.

https://en.wikipedia.org/wiki/Freeze-dried_ice_cream wrote:
<<Freeze-dried ice cream was developed by Whirlpool Corporation under contract to NASA for the Apollo missions so that foods could be sent on long-duration spaceflights, as to the Moon, and to reduce the weight of the water and oxygen normally found in food. Despite the common use of images of space walking astronauts in shuttle era space suits on packaging, freeze dried ice cream was not included on any Apollo, Skylab, Space Shuttle, or International Space Station missions. According to one NASA food scientist, although freeze-dried ice cream was developed on request, "it wasn't that popular." During the 1970s, astronauts ate regular ice cream on the Skylab space station and regular ice cream has also been eaten on the International Space Station.>>

BaldEagle wrote: ↑Sat Jan 25, 2020 2:42 pm Today's APOD is Rubins Galaxy. At the center, it appears to whirlpool down toward its singularity. If seen from the underside would it appear to whirlpool down as well?

rj rl wrote: ↑Sat Jan 25, 2020 9:59 am Wikipedia disagrees on the size of UGC 2885 being 800kly. It also claims that the largest known spiral galaxy is 'only' 650kly.

rj rl wrote: ↑Sat Jan 25, 2020 9:59 am
Wikipedia disagrees on the size of UGC 2885 being 800kly. It also claims that the largest known spiral galaxy is 'only' 650kly.

https://www.spacetelescope.org/news/heic2002/ wrote:

Hubble Surveys Gigantic Galaxy 6 January 2020

<<To kickstart the 30th anniversary year of the NASA/ESA Hubble Space Telescope, Hubble has imaged a majestic spiral galaxy. Galaxy UGC 2885 may be the largest known in the local universe. It is 2.5 times wider than our Milky Way and contains 10 times as many stars. The galaxy is also called “Rubin’s galaxy”, after astronomer Vera Rubin (1928–2016), by Benne Holwerda of the University of Louisville, Kentucky, who observed the galaxy with the Hubble Space Telescope. “My research was in large part inspired by Vera Rubin’s work in 1980 on the size of this galaxy,” said Holwerda>>

https://en.wikipedia.org/wiki/Reuben_sandwich wrote:

Click to play embedded YouTube video.

<<The Reuben sandwich is an American grilled sandwich composed of corned beef, Swiss cheese, sauerkraut, and Russian dressing, grilled between slices of rye bread. It is associated with kosher-style delicatessens, but it is not kosher, because it contains both meat and cheese. One origin story holds that Reuben Kulakofsky (his first name sometimes spelled Reubin; his last name sometimes shortened to Kay), a Jewish Lithuanian-born grocer residing in Omaha, Nebraska, was the inventor, perhaps as part of a group effort by members of Kulakofsky's weekly poker game held in the Blackstone Hotel from around 1920 through 1935. The participants, who nicknamed themselves "the committee", included the hotel's owner, Charles Schimmel. The sandwich first gained local fame when Schimmel put it on the Blackstone's lunch menu, and its fame spread when a former employee of the hotel won a national contest with the recipe. Mention is made of this sandwich in a scene within the movie Quiz Show (film), where Richard N. Goodwin (known as Dick) orders and eats one in a restaurant with Charles van Doren, and they discuss the sandwich's origins.>>

starsurfer wrote: ↑Sat Jan 25, 2020 1:25 pm Try finding it in this widefield image by Rogelio Bernal Andreo.

Space Telescope wrote about UGC 2885:

Despite its gargantuan size, researchers are calling it a “gentle giant” because it looks as if it has been sitting quietly over billions of years, possibly sipping hydrogen from the filamentary structure of intergalactic space. This is fuelling modest ongoing star birth at a rate half that of our Milky Way. In fact, its supermassive central black hole is also a sleeping giant; because the galaxy does not appear to be feeding on much smaller satellite galaxies, it is starved of infalling gas.

Spacetelescope wrote:

Researchers are still seeking to understand what led to the galaxy’s monstrous size. “It’s as big as you can make a disk galaxy without hitting anything else in space,” added Holwerda.

One clue is that the galaxy is fairly isolated in space and doesn’t have any nearby galaxies to crash into and disrupt the shape of its disc.