Hubble evidence pointing to ever-expanding universe

[Turner]

I recall this coming up in a previous thread. . . .

Hubble evidence pointing to ever-expanding universe

Findings support theory by Einstein in which 'dark energy' drives its growth

By Frank D. Roylance
Sun Staff
Originally published February 21, 2004
Astronomers using the Hubble Space Telescope say they have glimpsed the ultimate fate of the universe.
In what some are calling a landmark study, a team led by Adam Riess and Louis-Gregory Strolger said yesterday they have found the most reliable measure yet of the mysterious "dark energy" that's pushing everything in the universe apart.

Captured from the light of exploding stars, the data suggest that dark energy is pushing at a nearly constant rate, just as Albert Einstein predicted in 1920.

If those findings hold up, it means the universe will expand forever. Whatever galaxies, stars, planets and people are still around billions of years from now won't be ripped apart by runaway acceleration of that expansion - or crushed by its reversal into a "big crunch."

"This dark energy and cosmological acceleration are the deepest mystery in all science," said University of Chicago astrophysicist Michael S. Turner, who was not involved in the study. "This is the first time the measurements have been good enough to see whether or not the dark energy is changing with time ... I think it is a landmark."


Appeals for Hubble

Riess and other astronomers at the Space Telescope Science Institute in Baltimore immediately gave credit to Hubble, which faces an early retirement after a NASA decision to cancel its final servicing mission.

"The Hubble Space Telescope is the only tool able to peer far enough out in time and distance to observe these supernovae and track the rate of expansion of the universe over a large range of its history, and gauge the strength of dark energy," Riess said.

Neither the James Webb Space Telescope, scheduled for launch in 2011, nor the Spitzer Space Telescope, launched in August, can monitor the correct wavelengths, or scan a broad enough expanse of sky to search for the distant supernovae critical to measuring dark energy.

"Realistically, this problem will be with us for the next decade or two," Riess said. With Hubble expected to fail as early as 2007 if it's not serviced, he added, "I hope it isn't too long until there is some kind of dedicated telescope to do this kind of work."

Cosmologists, who study the origins, nature and fate of the universe, were startled in 1998 by the discovery that the expansion of the universe, which began with the Big Bang 13.7 billion years ago, was speeding up.

Some sort of "anti-gravity" force had overcome the expected attraction of all the matter in the universe, and was now pushing - or pulling - it apart at an accelerating rate. It was dubbed "dark energy."


Enduring mystery

Although the dark energy constitutes 70 percent of the total energy of the universe, "we don't have a clue what it is," said Mario Livio, a theorist on Riess' team in Baltimore.

To begin to explain it, Livio said, scientists needed to find a way to measure how strong this energy is, and whether it was changing over time. Riess' team attacked the problem by measuring how fast objects were moving at various times throughout the history of the universe.

To do that, they needed to put a kind of radar gun on objects at increasing distances from Earth. Because light from more distant objects began its journey to Earth longer ago than light from nearer objects, it's a way of looking back through time.

Riess' team chose Type 1A supernovas because they are so bright they can be seen by Hubble across billions of light-years.

It worked. The Hubble team found 16 faraway Type 1A supernovas, then measured their distance and the speed at which they appeared to be moving away from us. That gave them the expansion rates for the universe at the times when the light left each star.

Their accuracy was eight times better than in 1998, Riess said - good enough to determine when the expansion of the universe stopped slowing, and began to speed up - about 5 billion years ago.


Blunder no more

The study's bottom line is that the universe appears to be accelerating at something close to a constant rate.

And the strength of the dark energy is at least close to the value that Einstein predicted - his famous "cosmological constant," which he once dismissed as "my greatest blunder."

The more supernovas astronomers can locate and measure, the more precise their estimates of the expansion will become. But they will have to quadruple the number they find just to double their accuracy.

It won't be easy. "We need to search tens of thousands of galaxies to find one," Riess said.

But "at the very least," Livio added, "it appears that for the next 25 billion years or so, we may be safe. The universe is neither ripping apart nor recollapsing."

The Hubble team's paper has been accepted for publication by the Astrophysical Journal. It will be formally presented next week at a scientific conference in California.

 

[superslug]

So they cyclic theory of constant universal expansion and contraction would appear to be dead in the water, eh?

 

[Smidlee]

interesting but behind the scenes I hear a " Save the Hubble " message . This maybe just an attempt to get NASA to save the Hubble. (It doesn't matter to me if they save it or not)

 

[Bozo Erectus]

What would cause something thats slowing down to speed up? Was there no dark matter before 5 billion years ago? If there was, what happened to it 5 billion years ago? If it didnt exist 5 billion years ago, where did it come from? Fascinating stuff.

 

[Perfection]

@Dumb pothead

The forces were always present, but it wasn't until about 5 billion years ago that it counteracted the pulling forces of gravity

 

[Tassadar]

From:http://spaceflightnow.com/news/n0402/21darkenergy/


If the repulsion from dark energy is or becomes stronger than Einstein's prediction, the universe may be torn apart by a future "Big Rip," during which the universe expands so violently that first the galaxies, then the stars, then planets, and finally atoms come unglued in a catastrophic end of time. Currently this idea is very speculative, but being pursued by theorists.


I want to see this cosmic firework

 

[Bozo Erectus]

Originally posted by Perfection
@Dumb pothead

The forces were always present, but it wasn't until about 5 billion years ago that it counteracted the pulling forces of gravity

I know, Im wondering what changed 5 billion years ago that made the expansion start accelerating. Was the dark matter building up till it reached a crital mass and started the acceleration? Does 'regular' matter get converted into dark matter and it took until 5 billion years ago for their to be enough? If regular matter is constantly being converted into dark matter, how does it happen? Do black holes have something to do with it?
I know nobody knows, Im just thinking out loud

 

[John Bull]

Anybody been to Exit Mundi?

 

[Perfection]

Originally posted by Dumb pothead

I know, Im wondering what changed 5 billion years ago that made the expansion start accelerating. Was the dark matter building up till it reached a crital mass and started the acceleration? Does 'regular' matter get converted into dark matter and it took until 5 billion years ago for their to be enough? If regular matter is constantly being converted into dark matter, how does it happen? Do black holes have something to do with it?
I know nobody knows, Im just thinking out loud

No, it's differnet, there is no conversian. The current idea is that the amount matter and dark energy remained about the same, but gravity attenuates at longer distances while dark energy seems to increase strength so as the universe got bigger and bigger the accelerating foces of dark enrgy counteracted the deccelerating forces of gravity.

 

[Bozo Erectus]

Originally posted by Perfection
No, it's differnet, there is no conversian. The current idea is that the amount matter and dark energy remained about the same, but gravity attenuates at longer distances while dark energy seems to increase strength so as the universe got bigger and bigger the accelerating foces of dark enrgy counteracted the deccelerating forces of gravity.

Ahh ok, that makes sense. Thanks for the succinct explanation of the current theory

 

[Xen]

I knew it (remember a conversation with perfection about the end of the universe a while ago, in which I stated the universe will never end )

Next prediction- I want a Taco.

anyway, that said, the universe reversing into a big collaps, or expanding into oblivion dosent make much sense, for either of them, thw whole occams razor thing applies here, and simply put, for everything to just sort of disperse into a merky fashion into self oblivion, one would suspect that the beginnings of the action would have been occuring since the very beginning, barring anyout side force actionf upon the univers (by this I dont mean god, but more like some super advanced aliens makeing a distruct-o beam type thing, as persoanlly, I dont belive in the definition of deities actiong upon the universe, controlling it with thier utter whim, but thats for a different thread), and likewise, a big crunch dosent make any simple sense period.

 

[Bozo Erectus]

Well, the 'original' Cosmic Egg had to come from somewhere, which makes the oscillating universe sound perfectly logical. You get a Big Bang which inflates the universe, then eventually you get a Big Crunch and we're back where we started from with a new Cosmic Egg. Twenty years from now they'll discover 'Gray Matter' or something that will bring the oscillating universe back into vogue.

 

[Inter4]

http://www.space.com/scienceastronomy/dark_energy_040220.html

 

[Xen]

Originally posted by Dumb pothead
Well, the 'original' Cosmic Egg had to come from somewhere, which makes the oscillating universe sound perfectly logical. You get a Big Bang which inflates the universe, then eventually you get a Big Crunch and we're back where we started from with a new Cosmic Egg. Twenty years from now they'll discover 'Gray Matter' or something that will bring the oscillating universe back into vogue.

that makes no sense to me, as the only way that would be possible, is if

A)for somereason,m everything decides to reverse itslef oneday, which is unreasonable- theres no reason for it to reverse, sure its makeing newton turn in his grave right now, but simply fact is, theres no resoan fo rthe universe to suddenlly collapse upon itsle fin a giant wave of cosimic destruction; it makes about as much sense as a 7 foot basketball playewr oneday demorphing into an little Gnome

B)the only other wya I see it as being possibe is if the universe itsel fwas superimposed on a giant sphere, where evantualyl all the expanding waves would collide in uponitself, but considering the universe is spere is shape, and obviouslly not super-imposed upon one, that idea is even more fruity then the first

 

[Bozo Erectus]

If I understand the theory correctly, the universe doesnt decide to reverse course (BTW, it seems to have decided to accelerate 5 billion years ago). What happens is that the gravity of the mass of the universe slows the expansion and then slowly draws it all back in, till your back in the Big Crunch. Gravity warps space right? So all that mass rushing in towards itself would pull space-time right along with it.
Xen, if you reject both the Big Crunch and also the ever expanding theory, what are your own ideas about whats going on?

 

[Xen]

basically, that the distance between galxies will just ever exapand, while galxies themselves as long as whatever supere-powerfukl gravitycore is holding them together (I think ite love;... or Bill Murry- possibly both )

all said, I am in support of the everexpanding theory- just i find it absurd the idea that because the distance between galaixies is increasing means that eventually all matter will sperarate as well...

 

[Cecasander]

Does this officialy abolished the Theory of Creation (the theological yadiya)?

 

[Perfection]

Originally posted by Xen
basically, that the distance between galxies will just ever exapand, while galxies themselves as long as whatever supere-powerfukl gravitycore is holding them together (I think ite love;... or Bill Murry- possibly both )

all said, I am in support of the everexpanding theory- just i find it absurd the idea that because the distance between galaixies is increasing means that eventually all matter will sperarate as well...

Well, there's a lot more evidece then just logical connection, stars give off radiation that never gets replaced and so the galaxy loses mass/energy.

 

[Xen]

Originally posted by Perfection
Well, there's a lot more evidece then just logical connection, stars give off radiation that never gets replaced and so the galaxy loses mass/energy.

the universe itself lasting forever doeset mean that stars will- BUT that said, there is a never ending source of stars, meaning that while it is true that stars will die, there will always be new stars to take thier place

 

[Perfection]

Originally posted by Xen
the universe itself lasting forever doeset mean that stars will- BUT that said, there is a never ending source of stars, meaning that while it is true that stars will die, there will always be new stars to take thier place

There isn't a never ending source of stars.