Dark Energy Tied to Human Origins

Dark Energy Tied to Human Origins
By Robert Roy Britt
Senior Science Writer
31 May 2004

Among the most elusive and important questions in science are whether
we're alone and what the heck that strange stuff is that's pushing the
universe apart. Neither is likely to be answered anytime soon, yet
each occupies many great minds and together they drive billions of
dollars in research spending every year.

Now wouldn't it be really weird if these two seemingly unrelated
questions were intimately linked? Strange but possibly true, says
Mario Livio, a theorist at the Space Telescope Science Institute
(STScI).

Astronomers have known since the 1920s that the universe is expanding.
In 1998 they were astounded to learn that it is expanding at an
ever-increasing pace. The universe is accelerating, in other words.

Nobody has a clue what's up, so smart minds invoke a thing dubbed dark
energy to explain why gravity appears to have turned into a repulsive
force. They say this dark energy makes up 73 to 75 percent of the
mass-energy budget of the cosmos.

"It's the equivalent of us not knowing what water is," as Livio puts
it, "even though it covers 70 percent of the Earth."

Fundamentally accidental

One of astronomers' first tasks in this investigation is to determine
whether dark energy's repulsive strength changes over time or not.
They're working on it. By using the Hubble Space Telescope to discover
distant exploding stars whose light is stretched during travel through
time and space, researchers can see what the rate of expansion was
when the light left each object.

If dark energy's repulsive force decreases in strength with time, the
universe might eventually reverse course and collapse. If dark energy
gets stronger, things could get way out of hand in the other
direction, with all matter -- stars, planets, living things and atoms
-- being shredded in a Big Rip.

Preliminary results show things accelerating at a manageable pace for
billions of years to come.

Meanwhile, scientists are pretty sure that, whatever it is, dark
energy does indeed makes up 73 percent of everything. It's tempting to
call that a fundamental quantity of Nature. Livio resists that
temptation.

"The values of some constants of Nature may not be fundamental, but
rather accidental," he told a group of reporters who gathered at the
STScI in Baltimore earlier this month to hear what projects Hubble
would work on during its final years.

Livio cites the 17th Century astronomer and mathematician Johannes
Kepler, who wrote an entire book to explain the fundamental reasons
why there were six planets at certain distances from each other. The
math was fine for its time, and Kepler can be forgiven for not knowing
about the other planets yet, but it was the whole premise that was
wrong.

"He misunderstood the fact that the number of planets and the sizes of
their orbits were not fundamental quantities," Livio explained. "They
were accidental values for the conditions that happen to be in the
disk around the Sun."

Other planets around other stars, we know now, have wildly different
setups.

The kicker

What's that got to do with dark energy?

"It is very possible, though we don't know, that the very peculiar
value -- 73 percent or whatever it is -- of the dark energy is in fact
not a fundamental quantity," Livio said. "In order for this to happen,
you must have many universes."

And, Livio and other cosmologists argue, current theories for how our
universe began allow for an infinite number of what he calls "pocket
universes," of which we are just one.

"The values of some things like the dark energy could be different in
different pocket universes," Livio maintains. "But not all of them
would allow life. If the value of dark energy in our universe were
more than 10 times larger than it is, galaxies would never have
formed, and we wouldn't be here to talk about it."

http://www.space.com/scienceastronom...ay_040531.html

Suggestion: Take your argument to news:sci.physics

Similar to you reasoning we can't see pink elephants traveling
faster than the speed of light either.

"The time has come," the Walrus said, "To talk of many things:
Of shoes, and ships, and sealing wax, of cabbages and kings.
And why the sea is boiling hot and whether pigs have wings."

-- L. Carroll

Suggestion: Take your argument to news:sci.physics

Similar to you reasoning we can't see pink elephants traveling
faster than the speed of light either.

"The time has come," the Walrus said, "To talk of many things:
Of shoes, and ships, and sealing wax, of cabbages and kings.
And why the sea is boiling hot and whether pigs have wings."

-- L. Carroll