Hi! I'm new to Cosmology.

[Penumbra]

In fact, I'm new to all of these forums. I just finished reading Carl Sagan's "Cosmos", and I have to say the chapters pertaining to stars, galaxies, pulsars, quasars, matter of all kinds are extremely interesting. I was wondering though, if this information in the book/movie series has been at all turned against Dr. Sagan since the release in the early 1980's. How much has our knowledge changed about the Universe since the release?

 

Those who have read the book or seen the series, I welcome any comments, and to everyone else, any discussion (especially about galaxies).

 

The Universe is so incredibly vast and deep (physically) that I am compelled to dive into its most murky expanses and all its beauty. I mean, some of the artistic and scientific concept paintings of galaxies rising in the dawn of some planet light years above the galactic plane of our own Milky Way. It is truly amazing how this all works and molds together.

[metatron]

Welcome, Punumbra

Heres My systems veiw on how galaxies form.

 

 

http://www.scienceforums.net/forums/showthread.php?t=11027

 

What does Penumbra mean?

[Severian]

The most recent development in cosmology has been the studies on the cosmic microwave background radiation done by WMAP. I suggest you take a look at their website:

 

http://map.gsfc.nasa.gov/

 

they discovered lots of interesting new stuff: for example, it looks like the universe is open.

[Bettina]

The most recent development in cosmology has been the studies on the cosmic microwave background radiation done by WMAP. I suggest you take a look at their website:

 

http://map.gsfc.nasa.gov/

 

they discovered lots of interesting new stuff: for example' date=' it looks like the universe is open.[/quote']

 

I've been to this site many times and went there again just now. They say the universe is flat.... not open.

 

I still wonder if flat and open exist together. In other words, the universe is spherical in shape, expanding outward in all directions, but so huge, that it appears flat where we are measuring, yet open to expand forever....

 

Bettina

[Penumbra]

A Penumbra is the partial shadow surrounding the complete shadow (as seen in an eclipse), when two light sources come into contact with one object and project two shadows, one a fraction lighter than the other. It's also a mental health charity in Scotland and a heavy metal band somewhere in America.

 

http://www.exploratorium.edu/eclipse/why.html ~ A decent description.

[Penumbra]

Also, I was reading something interesting about when/if the Universe "stops" expanding. If this was not followed by a total, immediate crunch, what if it began shrinking again, at the same rate which it is currently expanding! Would things such as causality be reversed? The red and blue shifts of Doppler would switch, so would ripples appear in a pond before I throw a pebble? Would people be born in a grave, and die in the womb? >

[bascule]

<ot>

 

If there's one thing people stab in Carl Sagan's back it's the fact that he smoked marijuana

 

</ot>

[Severian]

I've been to this site many times and went there again just now. They say the universe is flat.... not open.

 

I still wonder if flat and open exist together. In other words' date=' the universe is spherical in shape, expanding outward in all directions, but so huge, that it appears flat where we are measuring, yet open to expand forever....

 

Bettina[/quote']

 

Yes, it is a bit confusing. When they say it is flat, they mean thet there is no curvature in the spacial directions. When they say it is open, they are meaning that it is open in the time direction - ie. that the universe will continue to expand forever and we won't have a big crunch.