Freethought & Rationalism Archive

trientalis · 03-07-2003, 06:14 PM

From Space.com the following article describes a new theory of the end of, well, everything.

take a look

This is the way the world ends, not with a bang but a rrriiiippp?

Friar Bellows · 03-07-2003, 09:33 PM

Results from supernova searches and recently WMAP seem to suggest that the expansion of the universe is accelerating. One possible reason for this apparent acceleration is that the universe contains some kind of dark energy which has a negative pressure. One way to characterise this dark energy is via an equation of state which relates its pressure to its energy density. The ratio between the pressure and the density is given the symbol, w.

If the dark energy is a cosmological constant, or acts like a cosmological constant (e.g. vacuum energy), then w = -1. If the dark energy is "quintessence", a kind of evolving scalar field which I have no clue about, then -1 < w < -1/3. Evidence from WMAP, type Ia supernovae, large-scale structure studies, and quasar-lensing statistics tends to support a value of w closer to -1 than -1/3.

But what about w < -1? This is what the "Big Rip" supporters are proposing. The dark energy in this case is termed "phantom energy" (talk about imaginative!

). With phantom energy (as opposed to the cosmological constant or quintessence), bound structures in the universe like galaxies, planetary systems and even atoms will ultimately get ripped apart, hence the "Big Rip". The table below shows the history and future of the universe with w = -3/2.

Ref: Phantom Energy and Cosmic Doomsday (Caldwell et al, astro-ph/0302506, 2003).

Badfish · 03-07-2003, 10:18 PM

Very cool!

Lobstrosity · 03-08-2003, 03:51 AM

Heh, what a great quote:

Quote:

When Earth explodes, the end is momentarily near.
At this point, there is still a short interval before atoms and even their nuclei break apart. "There's about 30 minutes left," Caldwell said, "But it's not quality time."

Jay30 · 03-08-2003, 07:46 PM

Just heard an interview with Dr. Robert Caldwell himself this morning on CBC Radio's Quirks and Quarks

You can hear the interview here:

The Big Rip

The mp3 is there about a third of the way down, under the subtitle: The Big Rip. It takes a minute or two to load.

Shake · 03-09-2003, 09:29 AM

Ohhhh! I thought this was some new theory wherein God created the Universe by letting a big one (fart) rip!

Seriously though, as it says right in the article:

Quote:

Scientifically it is just about the most repulsive notion ever conceived.

It sure is!

03-07-2003, 06:14 PM	#1
trientalis Senior Member Join Date: Sep 2001 Location: Washington state Posts: 848	The Big Rip From Space.com the following article describes a new theory of the end of, well, everything. take a look This is the way the world ends, not with a bang but a rrriiiippp?

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03-07-2003, 09:33 PM	#2
Friar Bellows Veteran Member Join Date: Apr 2001 Location: arse-end of the world Posts: 2,305	Results from supernova searches and recently WMAP seem to suggest that the expansion of the universe is accelerating. One possible reason for this apparent acceleration is that the universe contains some kind of dark energy which has a negative pressure. One way to characterise this dark energy is via an equation of state which relates its pressure to its energy density. The ratio between the pressure and the density is given the symbol, w. If the dark energy is a cosmological constant, or acts like a cosmological constant (e.g. vacuum energy), then w = -1. If the dark energy is "quintessence", a kind of evolving scalar field which I have no clue about, then -1 < w < -1/3. Evidence from WMAP, type Ia supernovae, large-scale structure studies, and quasar-lensing statistics tends to support a value of w closer to -1 than -1/3. But what about w < -1? This is what the "Big Rip" supporters are proposing. The dark energy in this case is termed "phantom energy" (talk about imaginative! ). With phantom energy (as opposed to the cosmological constant or quintessence), bound structures in the universe like galaxies, planetary systems and even atoms will ultimately get ripped apart, hence the "Big Rip". The table below shows the history and future of the universe with w = -3/2. Ref: Phantom Energy and Cosmic Doomsday (Caldwell et al, astro-ph/0302506, 2003).

03-07-2003, 10:18 PM	#3
Badfish Veteran Member Join Date: Jun 2002 Location: Death Valley, CA Posts: 1,738	Very cool!

03-08-2003, 07:46 PM	#5
Jay30 Junior Member Join Date: Nov 2002 Location: Gander, NF, Canada Posts: 9	Just heard an interview with Dr. Robert Caldwell himself this morning on CBC Radio's Quirks and Quarks You can hear the interview here: The Big Rip The mp3 is there about a third of the way down, under the subtitle: The Big Rip. It takes a minute or two to load.

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