The known universe

[lorin]

www.youtube.com/watch%3Fv%3D17jymDn0W6U

These are the days I wish I had a giant tv screen. Maintained by the Museum of Natural History.

[Orlion]

I don't have sound on the computer that I'm using, but at least visually that was incredible!

[Menolly]

Wow...
Stolen for Facebook.
Thanks lorin.

[lorin]

the problem for me is I just can't wrap my mind around it, the concept of infinity. freaks me out.

Guess I'm just a boundaries, finite kinda gal. too bad for me.

[matrixman]

I don't know if we're capable of wrapping our minds around infinity, lorin. Any person that could, wouldn't be able to share the experience with the rest of us anyway. But hey, that's why the infinity symbol was invented to spare us the trouble.

Fantastic video! Thanks, lorin, I love this sort of thing.

What blows my mind is the inflationary model - the idea that in the earliest moments of the universe, it expanded monstrously at many times faster than the speed of light, so that all that is known to us now represents only a tiny part of an incomprehensibly larger universe. That thought is both awesome and terrifying to me.

[dlbpharmd]

Beautiful video! Thanks for sharing.

[fragile granite]

This is the most current (and hopefully accurate) annotated depiction of the Milky Way Galaxy. Much research & work has gone into providing empirical data for this diagram. For the last two and a half years, I have been a physics major with emphasis on astrophysics at a university near St. Louis. Although I understand the concepts well enough from a verbal perspective, I lack the math skills necessary to be an astrophysicist. Even so, this subject remains near and dear to my heart. Thanks for sharing the youtube video link! I will attempt to share a bit of information as well.

[fragile granite]

What follows can be found at the Atlas of the Universe website.

The Universe within 12.5 ly



This diagram represents the closest neighboring stars of the sun.

This map shows all the star systems that lie within 12.5 light years of our Sun. Most of the stars are red dwarfs - stars with a tenth of the Sun's mass and less than one hundredth the luminosity. Roughly eighty percent of all the stars in the universe are red dwarfs, and the nearest star - Proxima - is a typical example.

For those of you who are into Star Trek-the Next Generation: do you remember that the Borg were fought and stopped at Wolf 359? Yes there really is a star by that name and it is depicted on this diagram.

[fragile granite]

The Universe within 250 Light Years
The Solar Neighborhood

This map is a plot of the 1500 most luminous stars within 250 light years. All of these stars are much more luminous than the Sun and most of them can be seen with the naked eye. About one third of the stars visible with the naked eye lie within 250 light years, even though this is only a tiny part of our galaxy.

This is only a small fraction of the total stars within 250 ly because most stars are smaller and less luminous than the sun. Atlas of the Universe calculates the total to be around 260,000 stars within a radius of 250 ly.

[fragile granite]

The Universe within 5000 Light Years
The Orion Arm

This is a map of our corner of the Milky Way galaxy. The Sun is located in the Orion Arm - a fairly minor arm compared with the Sagittarius Arm, which is located closer to the galactic centre. The map shows several stars visible with the naked eye which are located deep within the Orion arm. The most notable group of stars here are main stars in the constellation of Orion - from which the spiral arm gets its name. All of these stars are bright giant and supergiant stars, thousands of times more luminous than the Sun. The most luminous star on the map is Rho Cassiopeia (ρ Cas) - to us 4000 light years away, it is a dim naked eye star, but in reality it is a huge supergiant star 100 000 times more luminous than our Sun.

AoftheU estimates 6 million stars within a radius of 5000 ly.

[fragile granite]

The Universe within 50000 Light Years
The Milky Way Galaxy

This map shows the full extent of the Milky Way galaxy - a spiral galaxy of at least two hundred billion stars. Our Sun is buried deep within the Orion Arm about 26 000 light years from the centre. Towards the centre of the Galaxy the stars are packed together much closer than they are where we live. Notice also the presence of small globular clusters of stars which lie well outside the plane of the Galaxy, and notice too the presence of a nearby dwarf galaxy - the Sagittarius dwarf - which is slowly being swallowed up by our own galaxy.

This diagram is older and somewhat less accurate but it still conveys a sense of the sun's placement within our local universe of the Milky Way Galaxy. There is estimated to be at least 200 billion stars in the MWG.

[fragile granite]

The Universe within 500000 Light Years
The Satellite Galaxies

The Milky Way is surrounded by several dwarf galaxies, typically containing a few tens of millions of stars, which is insignificant compared with the number of stars in the Milky Way itself. This map shows the closest dwarf galaxies, they are all gravitationally bound to the Milky Way requiring billions of years to orbit it.

AoftheU's estimate of 225 billion stars is probably low, but even so, this diagram conveys a sense of structure and scale.

[fragile granite]

The Universe within 5 million Light Years
The Local Group of Galaxies

The Milky Way is one of three large galaxies belonging to the group of galaxies called the Local Group which also contains several dozen dwarf galaxies. Most of these galaxies are depicted on the map, although most dwarf galaxies are so faint, that there are probably several more waiting to be discovered.

A sense of scale and structure continues as each diagram includes a much greater volume of space. There are easily 700 billion stars within a radius of 5 million ly.

[dlbpharmd]

thanks, FG!

[fragile granite]

The Universe within 5 million Light Years
The Local Group of Galaxies

The Milky Way is one of three large galaxies belonging to the group of galaxies called the Local Group which also contains several dozen dwarf galaxies. Most of these galaxies are depicted on the map, although most dwarf galaxies are so faint, that there are probably several more waiting to be discovered.

A sense of scale and structure continues as each diagram includes a much greater volume of space. There are easily 700 billion stars within a radius of 5 million ly.

The Nearest Groups of Galaxies

This is a map of galaxies that lie within 20 million light years plotted onto the supergalactic plane. Nearly all of the nearby galaxies lie near this plane (the supergalactic coordinate system was originally invented because many nearby galaxy groups lie close to this plane.) All of the brightest and largest galaxies within 20 million light years are marked on this map together with many of the fainter dwarf galaxies.

This is only a tiny fraction of the known universe. A universe so vast it is indeed difficult to wrap your mind around it. Still, IMO diagrams like these helps.

[fragile granite]

You're welcomed, dlbpharmd! If you are interested, I'd like to recommend:

The Astronomy Nexus

Windows to the Universe

Solstation

Students for the Exploration and Development of Space (SEDS) [and]

Wilkinson Microwave Anisotropy Probe

for further study and self-education on this most fascinating topic! For those members who are interested in the search for Exoplanets I'd like to recommend:

Planetquest

California Planet Search [and]

The Planetary Society

Have fun!

[fragile granite]

Another video which has been around for many years and I've seen in at least four classes, is called "the Powers of Ten." It also conveys a sense of scale which most deffinitely helps us to wrap our minds around the known universe.

[lorin]

Another video which has been around for many years and I've seen in at least four classes, is called "the Powers of Ten." It also conveys a sense of scale which most deffinitely helps us to wrap our minds around the known universe.

that is very cool, especially a journey in both directions. have to say, though, it only makes it more difficult to grasp the scope. Just adds another direction to infinity.

[fragile granite]

OK lorin, how about the Simpsons' version?

www.youtube.com/watch?v=7GDC3u8k02c

Maybe the finite mind does have trouble wrapping around the infinite due to some inherent limitations. But then again, life is able to communicate with life, so perhaps consciousness gradually evolves from the finite to the infinite...such evolving people are overcoming these limitations and do indeed hear music that others cannot hear and dance with many joyful reasons to be alive!

[lorin]

OK lorin, how about the Simpsons' version?

www.youtube.com/watch?v=7GDC3u8k02c

Maybe the finite mind does have trouble wrapping around the infinite due to some inherent limitations. But then again, life is able to communicate with life, so perhaps consciousness gradually evolves from the finite to the infinite...such evolving people are overcoming these limitations and do indeed hear music that others cannot hear and dance with many joyful reasons to be alive!

that's just a tiny bit too finite!

I am working on those limitations. I'm hoping that someday I will be able to grasp those fluid concepts that have eluded me. In the meantime I really appreciate that you appreciate my little Nietzscheisim.