Astronomy
Sep 4, 2017 12:14:41 #
"Is this what will become of our Sun? Quite possibly. The bubble of expanding gas pictured below is the planetary nebula PK 164 +31.1, the remnants of the atmosphere of a Sun-like star expelled as its supply of fusion-able core hydrogen became depleted. Visible near the center of the nebula is what remains of the core itself- a blue-hot white dwarf star. This particularly photogenic planetary nebula shows intricate shells of gas likely expelled at different times toward the end the star's demise, and whose structure is not fully understood.
This deep image of PK 164 +31.1 from the Calar Alto Observatory in Spain shows many other stars from our own Milky Way Galaxy as well as several galaxies far in the distance. PK 164 +31, also known as Jones-Emberson 1, lies about 1,600 light years away toward the constellation of the Wildcat (Lynx). Due to its faintness (magnitude 17) and low surface brightness, the object is only visible with a good-sized telescope. Although the expanding nebula will fade away over the next few thousand years, the central white dwarf may well survive for billions of years- to when our universe may be a very different place.”
- http://apod.nasa.gov/apod/ap121030.html
“Here is a stunning Hubble Space Telescope photo from APOD (Astronomy Picture of the Day). Two galaxies, collectively known as Arp 273, encountering each other so closely that gravity is distorting their spirals. Two galaxies engaged in a cosmic dance.
http://3.bp.blogspot.com/-y44VTGCD71Q/TbYp9Bx3FmI/AAAAAAAAecQ/1zWrkYIREdE/s1600/Galaxies.jpg
Let me say a bit more about what we are looking at than APOD provided. Two galaxies, one neatly wrapped, one with out-flung arms. The one at the top is about the size of our own Milky Way galaxy, although more lop-sided due to the gravitational pull of its partner. Perhaps it contains a hundred billion stars, separated (as in the Milky Way) by light years. We are seeing in the photo only the relatively rare and exceptionally bright blue and red giants. If we were on a planet of a sun-like star in the upper galaxy, oh how magnificent would be the companion galaxy in our night sky! The bright stars in the photograph with diffraction spikes are in our own Milky Way, very much in the foreground.
Imagine our Milky Way Galaxy - a hundred thousand light-years wide - as a dinner plate. We are on a planet of a star about two-thirds of the way out toward the edge. When we look at Arp 273 we are looking down and out of the dinner plate, at an angle to the plate and towards the edge. The Arp 273 galaxies would be a dinner plate and a salad plate about a kilometer away. (The nearest spiral galaxy to us, the Great Galaxy in Andromeda, would be a dinner plate just across the room.)
Arp 273 takes up about as much of the sky as would a pinhead held at arm's length. And look what else is in the photo. I count at least a few dozen other galaxies, vastly more distant - all those little elongated blurs in the background. Every one of those galaxies contains hundreds of billions of stars.
- http://blog.sciencemusings.com/
This deep image of PK 164 +31.1 from the Calar Alto Observatory in Spain shows many other stars from our own Milky Way Galaxy as well as several galaxies far in the distance. PK 164 +31, also known as Jones-Emberson 1, lies about 1,600 light years away toward the constellation of the Wildcat (Lynx). Due to its faintness (magnitude 17) and low surface brightness, the object is only visible with a good-sized telescope. Although the expanding nebula will fade away over the next few thousand years, the central white dwarf may well survive for billions of years- to when our universe may be a very different place.”
- http://apod.nasa.gov/apod/ap121030.html
“Here is a stunning Hubble Space Telescope photo from APOD (Astronomy Picture of the Day). Two galaxies, collectively known as Arp 273, encountering each other so closely that gravity is distorting their spirals. Two galaxies engaged in a cosmic dance.
http://3.bp.blogspot.com/-y44VTGCD71Q/TbYp9Bx3FmI/AAAAAAAAecQ/1zWrkYIREdE/s1600/Galaxies.jpg
Let me say a bit more about what we are looking at than APOD provided. Two galaxies, one neatly wrapped, one with out-flung arms. The one at the top is about the size of our own Milky Way galaxy, although more lop-sided due to the gravitational pull of its partner. Perhaps it contains a hundred billion stars, separated (as in the Milky Way) by light years. We are seeing in the photo only the relatively rare and exceptionally bright blue and red giants. If we were on a planet of a sun-like star in the upper galaxy, oh how magnificent would be the companion galaxy in our night sky! The bright stars in the photograph with diffraction spikes are in our own Milky Way, very much in the foreground.
Imagine our Milky Way Galaxy - a hundred thousand light-years wide - as a dinner plate. We are on a planet of a star about two-thirds of the way out toward the edge. When we look at Arp 273 we are looking down and out of the dinner plate, at an angle to the plate and towards the edge. The Arp 273 galaxies would be a dinner plate and a salad plate about a kilometer away. (The nearest spiral galaxy to us, the Great Galaxy in Andromeda, would be a dinner plate just across the room.)
Arp 273 takes up about as much of the sky as would a pinhead held at arm's length. And look what else is in the photo. I count at least a few dozen other galaxies, vastly more distant - all those little elongated blurs in the background. Every one of those galaxies contains hundreds of billions of stars.
- http://blog.sciencemusings.com/
If you want to reply, then register here. Registration is free and your account is created instantly, so you can post right away.