Starship Asterisk*

SouthEastAsia wrote:Fascinating! Thanks APOD and thanks ESA!

Ok, my first question is: is dark energy connected in any way to formation of new star systems?

And second question is: assuming that our Universe is expanding at roughtly 67 km/sec... what exactly is the matter that it is expanding into?

Thanks in advance!

bystander wrote:
The universe is not expanding into anything. Nothing exists outside the universe.

Ann wrote:

bystander wrote:
The universe is not expanding into anything. Nothing exists outside the universe.

May I perhaps sort of disagree.

The universe isn't expanding into anything, no. From our point of view, the universe is everything. From our point of view, there can be nothing outside the universe.

But there just might be other universes. If so, they exist outside our universe.

Of course, we will never be able to see or otherwise detect any of these other, possible universes.

That's how I understand it anyway.

Ann

Bruised cosmos
Planck has also confirmed WMAP's detection of a large unexplained cold spot in the CMB, which some cosmologists took as a sign that there are universes beyond our own. One model of inflation, called eternal inflation, suggests that new universes are continually popping into existence (Note by Margarita - see quotation and link below) and expanding. This expansion could cause another universe to collide with ours, creating a "bruise" that would show up as a cold spot in the sky.

Microwave radiation map hints at other universes

Update on 16 August 2011: The researchers ran additional statistical checks on the CMB data, looking at the probability that the bubbles would appear anywhere on the sky. Lead author Stephen Feeney says: "The current data favour no bubble collisions. However, a non-zero number of bubble collisions is still allowed, and there are four patches in the WMAP data where [signals of possible bubble universes] are higher than anything we expect from systematic errors due to instrumental effects, foreground-removal artefacts etc. With data from Planck we expect our pipeline to be sensitive to much weaker collision signals, so we should be able to test whether there is something there or whether they're just weird patches of CMB." The updated analysis appears in Physical Review Letters (DOI: 10.1103/PhysRevLett.107.071301).

zbvhs wrote:
We now know the age of the universe to four significant figures.

http://en.wikipedia.org/wiki/Planck_%28spacecraft%29 wrote:
Age of the universe 13.798±0.037 Ga

[Planck - 68% limits (Planck+WP+highL+BAO)]

zbvhs wrote:
All very interesting but what do we do with it?

http://www.lhup.edu/~dsimanek/sciurban.htm wrote:
<<Benjamin Franklin observes the first balloon ascension in 1783 while he was Ambassador at the Court of France. Someone asks "What possible use are balloons?" Franklin answers "What use is a newborn baby?">>

zbvhs wrote:
The ancient Maya did astronomy for centuries and the only technology produced from it was three calendars. When the crunch came, their calendars weren't much use in preventing the collapse of Mayan society. So, how will knowing the age of the universe prevent the coming collapse of modern society, which some say is inevitable?

http://en.wikipedia.org/wiki/Maya_civilization wrote:
<<The Maya is a Mesoamerican civilization, noted for the only known fully developed written language of the pre-Columbian Americas, as well as for its art, architecture, and mathematical and astronomical systems. Initially established during the Pre-Classic period (c. 2000 BC to AD 250), according to the Mesoamerican chronology, many Maya cities reached their highest state of development during the Classic period (c. AD 250 to 900), and continued throughout the Post-Classic period until the arrival of the Spanish. Today, the Maya and their descendants form sizable populations throughout the Maya area and maintain a distinctive set of traditions and beliefs that are the result of the merger of pre-Columbian and post-Conquest ideas and cultures. Millions of people speak Mayan languages today.>>

Redbone wrote:Would we recognize a random distribution of the microwave background if we saw it? Random most definitely does not imply uniform, a random distribution will show patterns of high and low concentrations, just not in any predictable way.

zbvhs wrote:We now know the age of the universe to four significant figures. All very interesting but what do we do with it?

So, how will knowing the age of the universe prevent the coming collapse of modern society, which some say is inevitable?

Shamanomaha wrote:Is the cosmic microwave background radiation the same as the Zero Point Field?

Neufer wrote:
<<Benjamin Franklin observes the first balloon ascension in 1783 while he was Ambassador at the Court of France. Someone asks "What possible use are balloons?" Franklin answers "What use is a newborn baby?">>

Chris Peterson wrote:

zbvhs wrote:
So, how will knowing the age of the universe prevent the coming collapse of modern society, which some say is inevitable?

Even if society collapses, it will be followed up by new civilizations and cultures, which will inherit much from us.

• 1) Never get involved in a land war in Asia.
  2) Never go against a Sicilian when death is on the line!

MargaritaMc wrote:

Ann wrote:

bystander wrote:
The universe is not expanding into anything. Nothing exists outside the universe.

May I perhaps sort of disagree.

The universe isn't expanding into anything, no. From our point of view, the universe is everything. From our point of view, there can be nothing outside the universe.

But there just might be other universes. If so, they exist outside our universe.

Of course, we will never be able to see or otherwise detect any of these other, possible universes.

That's how I understand it anyway.

Ann

http://www.newscientist.com/mobile/article/dn23301

Bruised cosmos
Planck has also confirmed WMAP's detection of a large unexplained cold spot in the CMB, which some cosmologists took as a sign that there are universes beyond our own. One model of inflation, called eternal inflation, suggests that new universes are continually popping into existence (Note by Margarita - see quotation and link below) and expanding. This expansion could cause another universe to collide with ours, creating a "bruise" that would show up as a cold spot in the sky.

http://www.newscientist.com/mobile/arti ... erses.html

Microwave radiation map hints at other universes

Update on 16 August 2011: The researchers ran additional statistical checks on the CMB data, looking at the probability that the bubbles would appear anywhere on the sky. Lead author Stephen Feeney says: "The current data favour no bubble collisions. However, a non-zero number of bubble collisions is still allowed, and there are four patches in the WMAP data where [signals of possible bubble universes] are higher than anything we expect from systematic errors due to instrumental effects, foreground-removal artefacts etc. With data from Planck we expect our pipeline to be sensitive to much weaker collision signals, so we should be able to test whether there is something there or whether they're just weird patches of CMB." The updated analysis appears in Physical Review Letters (DOI: 10.1103/PhysRevLett.107.071301).

expanding_universe.jpeg

Margarita

Anthony Barreiro wrote:... It seems like asking for trouble to speculate about a multitude of other universes that we will never see. My own personal belief is that we will never know everything, our theories and models will always be imperfect, and even this one universe will always be bigger, more complex, and more mysterious than we can possibly understand. Still, there is great value in striving for greater knowledge and understanding. And to have a better map of the universe 380,000 years after the big bang than we had a few years ago is an impressive accomplishment.

Max Tegmark My research is focused on precision cosmology, e.g., combining theoretical work with new measurements to place sharp constraints on cosmological models and their free parameters. ... Spectacular new measurements are providing powerful tools for this:
...
Every time I've written ten mainstream papers, I allow myself to indulge in writing one wacky one, like my Scientific American article about parallel universes. This is because I have a burning curiosity about the ultimate nature of reality; indeed, this is why I went into physics in the first place. So far, I've learned one thing in this quest that I'm really sure of: whatever the ultimate nature of reality may turn out to be, it's completely different from how it seems.

ignacio_db wrote:Basic question: When referring to percentages of dark matter, dark energy and "regular" matter, in terms of what is that proportion exactly? Is it in terms of energy, as in E=mc2 for "regular" matter? Or is it in terms of how dark terms weight versus "regular" matter gravity? Or is it some other way of comparing? How does massless radiation enter the picture?

Chris Peterson wrote:

ignacio_db wrote:Basic question: When referring to percentages of dark matter, dark energy and "regular" matter, in terms of what is that proportion exactly? Is it in terms of energy, as in E=mc2 for "regular" matter? Or is it in terms of how dark terms weight versus "regular" matter gravity? Or is it some other way of comparing? How does massless radiation enter the picture?

The ratios refer to energy only. That is, they take the entire energy content of the Universe and break it up into its three primary constituents: dark energy, dark matter, and ordinary matter (with the energy based on the energy equivalence of the two matter components). While the energy of photons was dominant early in the Universe, it now represents only a fraction of a percent of the energy of matter, so is typically disregarded in the published ratios.

http://cosmology.berkeley.edu/Education/CosmologyEssays/The_Cosmic_Microwave_Background.html wrote:
How do we learn about dark matter from the CMB?
Most of the cosmological information we get from the CMB is found by studying its power spectrum, a plot of the amount of fluctuation in the CMB temperature spectrum at different angular scales on the sky. The upper plot at right shows measurements of the power spectrum as of 2003 - large angular scales are at the left of the plot, while smaller sky features contribute to the right of the plot. 

The shape of this power spectrum is determined by oscillations in the hot gas of the early universe, and the resonant frequencies and amplitudes of these oscillations (which "notes" the universe likes to play!) are determined by its composition. Since we know the physics of hot gases very well, we can compute the properties of the oscillating gas by studying the positions and relative sizes of these peaks. The position of the first peak, for example, tells us about the curvature of the universe (and hence how much total stuff there is in it), while the ratio of heights between the first and second peaks tells us how much of the matter is baryonic (ordinary matter). In practice, there are many variables that affect all parts of the power spectrum, and detailed computer simulations (the red curve in the plot) are used to sort it all out.