barkis Posted March 7, 2016 Share Posted March 7, 2016 I came across the Image this morning, in a News Bulletin, so I thought I might place it on SGL, to let the unaware, become aware, of the vastness out there, and in particular the following. The Star is VY Canis Majoris, and it is shown in a comparison to our sun. the small rectangle at the bottom also indicates our suns comparative size. VY Canis Maj. is one of the largest and luminous d=stars known, and was at one time the largest. It has a diameter of 13.2 Astronomical Units, our sun earth distance being One AU. It is 3,900 light of years from Earth. If the star was placed at the centre of the Solar System, It's physical size would extend beyond the Orbit of Jupiter. It is also a Semi Regular Variable, with a period of 2,000 days. There are some variations in the estimates of it's radius. Isn't that vast Cosmos just full of interesting stuff? CREDITS. (Data extracted from Wiki) Link to comment Share on other sites More sharing options...
Knighty2112 Posted March 7, 2016 Share Posted March 7, 2016 That's a big star! ? Link to comment Share on other sites More sharing options...
WobblySkipper Posted March 7, 2016 Share Posted March 7, 2016 That is a really big star - its helps to put things into perspective. Jim Link to comment Share on other sites More sharing options...
Ruud Posted March 7, 2016 Share Posted March 7, 2016 It is enormous. Wiki says the radius is 1420 times that of the Sun, and its mass is 17 solar masses. That makes its density 17 / 14203 = 0.0000000059 times that of the Sun, which works out to 0.0000083 kg/m3. At sea level, our atmosphere has a density of 1.2 kg/m3, so VY Canis Majoris is a whole lot of almost nothing! Link to comment Share on other sites More sharing options...
Joe12345 Posted March 7, 2016 Share Posted March 7, 2016 That is big! I thought 1 AU was the distance from the sun to earth, not the diameter of the sun. 1.46*10^8km, if I remember correctly. Link to comment Share on other sites More sharing options...
Vox45 Posted March 7, 2016 Share Posted March 7, 2016 52 minutes ago, Joe12345 said: That is big! I thought 1 AU was the distance from the sun to earth, not the diameter of the sun. 1.46*10^8km, if I remember correctly. 4 hours ago, barkis said: The Star is VY Canis Majoris has a diameter of 13.2 Astronomical Units, our sun being One AU. I had to look this up: from Wiki: "The solar radius is approximately 695,700 kilometres (432,288 miles), which is about 1/215th of an astronomical unit" Wiki: A more recent and accurate VLTI measurement gives the star VY Canis Majoris a radius of 1420 ± 120 solar radii So, 1420 solar radii * (1/215th of an AU) = 6.6 AU radius = 13 AU diameter That is big! Link to comment Share on other sites More sharing options...
barkis Posted March 7, 2016 Author Share Posted March 7, 2016 3 hours ago, Vox45 said: I had to look this up: from Wiki: "The solar radius is approximately 695,700 kilometres (432,288 miles), which is about 1/215th of an astronomical unit" Wiki: A more recent and accurate VLTI measurement gives the star VY Canis Majoris a radius of 1420 ± 120 solar radii So, 1420 solar radii * (1/215th of an AU) = 6.6 AU radius = 13 AU diameter That is big! An Astronomical Unit is the Earth Sun distance, so 13.2 AU x (Earth Sun distance), is YV Can. Maj. diameter. Perhaps I ought to have cut and pasted Wiki's exact text, but It's something I don't practice much. Smacks of Idleness, but it might have prevented confusion in this case . Our figures differ by .2 AU, hardly worth worrying about. I'm sure in due course, the data of this giant will change again. Link to comment Share on other sites More sharing options...
Vox45 Posted March 8, 2016 Share Posted March 8, 2016 14 hours ago, barkis said: An Astronomical Unit is the Earth Sun distance, so 13.2 AU x (Earth Sun distance), is YV Can. Maj. diameter. Perhaps I ought to have cut and pasted Wiki's exact text, but It's something I don't practice much. Smacks of Idleness, but it might have prevented confusion in this case . Our figures differ by .2 AU, hardly worth worrying about. I'm sure in due course, the data of this giant will change again. I was not trying to correct you on this I was just trying to dispel confusion about the radius of the sun as being 1/215th of an AU and not a diameter of 1 AU as originaly posted. 22 hours ago, barkis said: It has a diameter of 13.2 Astronomical Units, our sun being One AU. I assure you, I was not trying to be pedant about it. It was more for my own understanding and love of discussion about things astro Great post by the way ! it keeps things in perspective Link to comment Share on other sites More sharing options...
barkis Posted March 8, 2016 Author Share Posted March 8, 2016 1 hour ago, Vox45 said: I was not trying to correct you on this I was just trying to dispel confusion about the radius of the sun as being 1/215th of an AU and not a diameter of 1 AU as originaly posted. I assure you, I was not trying to be pedant about it. It was more for my own understanding and love of discussion about things astro Great post by the way ! it keeps things in perspective Not to worry, I didn't intend to seem I was fussy, I was more concerned I had possibly misled you, or anyone else who joined the thread. I never get upset, life's too short anyway. It is important that details are in the main correct, and members have every right to ensure they are. We can all learn something new, and we have vast pool of knowledge on SGL. . Link to comment Share on other sites More sharing options...
Ruud Posted March 8, 2016 Share Posted March 8, 2016 Link to comment Share on other sites More sharing options...
Dave In Vermont Posted March 8, 2016 Share Posted March 8, 2016 That is one BIG star! Thanks for boggling my mind! Dave Link to comment Share on other sites More sharing options...
barkis Posted March 8, 2016 Author Share Posted March 8, 2016 I wonder what the escape velocity is ? . Not that anyone will ever be parked there, and wishing to get off it . Link to comment Share on other sites More sharing options...
Sam Posted March 9, 2016 Share Posted March 9, 2016 The scale is mind boggling. It's this sort of stuff that makes astronomy amazing, the sizes, distances and time scales are at the edge of what is imaginable (sometimes beyond). Link to comment Share on other sites More sharing options...
iPeace Posted March 9, 2016 Share Posted March 9, 2016 Great. Just when we think we've sorted it out, someone comes along with an even bigger sun. Can't we just stick to the plan? Nice one, thanks. Link to comment Share on other sites More sharing options...
symesie04 Posted March 9, 2016 Share Posted March 9, 2016 Mind boggling. And in the same vein i was reading about IC1101 which is the largest currently known galaxy at nearly 2 million light years across. " Just how large is it? At its largest point, this galaxy extends about 2 million light-years from its core, and it has a mass of about 100-trillion stars. To give you some idea of what this means, the Milky Way is just 100,000 light-years in diameter. If our galaxy were to be replaced with this super-giant, it would swallow up both Magellanic clouds, the Andromeda galaxy, the Triangulum galaxy, and almost all the space in between. That is simply staggering. " http://futurism.com/ic-1101-the-largest-galaxy-ever-found/ Just crazy crazy stuff. Link to comment Share on other sites More sharing options...
mikeyscope Posted March 10, 2016 Share Posted March 10, 2016 Ok guys who ate all the nebula? ....awww ...who do you think, it was that VY Canis Majoris over there ...look at him ....even ate all the tasty dark nebula! Link to comment Share on other sites More sharing options...
joe1950 Posted March 20, 2016 Share Posted March 20, 2016 I've been fascinated by VY Canis Majoris ever since I read about it several months ago. On some lists it is the largest known star in the Universe. Other lists, name other stars, but it is among the largest. For comparison sake, it is said that the sun could hold approximately 1 million earths, VY Canis Majoris can hold approximately one billion Suns. I haven't done so yet, but the star is visible in a modest scope or binos and I plan to have a look-see. It is about 8th magnitude currently. Of course, it will appear quite ordinary. But knowing what it actually is will add a thrill to the view, I'm sure. Looking at Canis Major, it is south near the tail area and to the east. Link to comment Share on other sites More sharing options...
saac Posted March 20, 2016 Share Posted March 20, 2016 There are some lovely videos on YouTube that show size comparison starting with planets in the solar system then the sun and through various stars ending with VY Canis Majoris. I've used this one in the classroom and it really does get you thinking about scale. I haven't checked the maths but I like the comparison at the end which shows the time it would take a passenger jet to fly around the star - lovely perspective that let's you get your head around the massive size of the thing. The Biggest Stars In The Universe - You Tube Jim Link to comment Share on other sites More sharing options...
michaelmorris Posted March 20, 2016 Share Posted March 20, 2016 On 07 March 2016 at 17:06, Vox45 said: I had to look this up: from Wiki: "The solar radius is approximately 695,700 kilometres (432,288 miles), which is about 1/215th of an astronomical unit" Wiki: A more recent and accurate VLTI measurement gives the star VY Canis Majoris a radius of 1420 ± 120 solar radii So, 1420 solar radii * (1/215th of an AU) = 6.6 AU radius = 13 AU diameter That is big! And I thought it was it was a long way to the shops! Link to comment Share on other sites More sharing options...
Connacht Posted March 20, 2016 Share Posted March 20, 2016 Simply amazing ! Blows my mind to consider the size of these massive giants ! Link to comment Share on other sites More sharing options...
symesie04 Posted March 21, 2016 Share Posted March 21, 2016 21 hours ago, saac said: There are some lovely videos on YouTube that show size comparison starting with planets in the solar system then the sun and through various stars ending with VY Canis Majoris. I've used this one in the classroom and it really does get you thinking about scale. I haven't checked the maths but I like the comparison at the end which shows the time it would take a passenger jet to fly around the star - lovely perspective that let's you get your head around the massive size of the thing. The Biggest Stars In The Universe - You Tube Jim Good video but yes i think their maths is flawed. I make it 355 years to orbit it once, but i t could be my maths. Link to comment Share on other sites More sharing options...
Stub Mandrel Posted March 21, 2016 Share Posted March 21, 2016 Only looks about 2" across on my monitor... When my daughter was small one of her favourite books was 'Is a Blue Whale the Biggest Thing There Is?" which went on scaling up bigger and bigger with things such as crates of 'Sun-sized oranges' and comparing them to the red giant Betelgeuse. Link to comment Share on other sites More sharing options...
Grotemobile Posted March 21, 2016 Share Posted March 21, 2016 Very good video. Liked the music as well Steve. Link to comment Share on other sites More sharing options...
nameunknown Posted March 23, 2016 Share Posted March 23, 2016 On 20/03/2016 at 00:29, joe1950 said: I've been fascinated by VY Canis Majoris ever since I read about it several months ago. On some lists it is the largest known star in the Universe. Other lists, name other stars, but it is among the largest. For comparison sake, it is said that the sun could hold approximately 1 million earths, VY Canis Majoris can hold approximately one billion Suns. I haven't done so yet, but the star is visible in a modest scope or binos and I plan to have a look-see. It is about 8th magnitude currently. Of course, it will appear quite ordinary. But knowing what it actually is will add a thrill to the view, I'm sure. Looking at Canis Major, it is south near the tail area and to the east. If you like looking at "odd" stars you might want to have a peek at HD 140283 - in Libra (https://en.wikipedia.org/wiki/HD_140283) - it is known as the "Methuselah" star because it is believed to be almost as old as the universe (it is about mag 7.2). It got a pensioner's bus-pass before Yoda was even born, and is probably the closest Population II star to earth. Given that it is very poor in "metals" (other than a bit of lithium), it possibly doesn't have much in the way of potentially habitable planets, let alone planets with very, very old ruins on them that could feature in some "Star Trek" episode (complete with "Greek" architecture so you know the ruins are old). P Link to comment Share on other sites More sharing options...
Stub Mandrel Posted March 23, 2016 Share Posted March 23, 2016 23 minutes ago, nameunknown said: Given that it is very poor in "metals" (other than a bit of lithium), it possibly doesn't have much in the way of potentially habitable planets, let alone planets with very, very old ruins on them that could feature in some "Star Trek" episode (complete with "Greek" architecture so you know the ruins are old). P Perhaps a distinctive rock instead... Link to comment Share on other sites More sharing options...
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