SAN DIEGO -- If you're light, it's fairly easy to travel at your own speed --
that is to say 186,282 miles per second or 299,800 kilometers per second.
But if you are matter, then it's another matter altogether.
Nothing we know of zips along more quickly than light. Einstein, nearly 100
years ago, said it's not possible. For us, the speed limit makes strange sense:
Go faster than light, and you could return before you've left, become your own
grandpa, or perform other leaps of cosmic logic.
Fast forward a century. Astronomers are now measuring stuff -- material, matter,
things -- that moves at so close to the speed of light you might think it'd
make Einstein a bit nervous. His theory of relativity appears not to be endangered
by the blazing speeds, though.
Among thee speed demons of the universe are Jupiter-sized blobs of hot gas
embedded in streams of material ejected from hyperactive galaxies known as blazars.
Last week at a meeting here of the American Astronomical Society, scientists
announced they had measured blobs in blazar jets screaming through space at
99.9 percent of light-speed.
"This tells us that the physical processes at the cores of these galaxies ...
are extremely energetic and are capable of propelling matter very close to the
absolute cosmic speed limit," said Glenn Piner of Whittier College in Whittier,
California.
Ponder the power of the fast moving superheated gas, known as plasma:
"To accelerate a bowling ball to the speed newly measured in these blazars
would require all the energy produced in the world for an entire week," Piner
said. "And the blobs of plasma in these jets are at least as massive as a large
planet."
The blazar jets are running around the universe in some fast company. Slightly
faster, in fact.
In another
study presented at the meeting, ultra high-energy cosmic rays thought to
originate in a collision of galaxy clusters are slamming into Earth's atmosphere
at more than 99.9 percent of the speed of light. Measurements put the number
at 99.9 followed by 19 more nines -- about as close to light-speed as you can
get without splitting hairs.
The particles are not light, but actual matter. They are tiny, thought to be
mostly protons, but the energy that motivates them is similarly fantastic, and
the mechanisms may be intertwined.
Scientists still don't know the exact mechanisms involved in accelerating matter
to such high speeds, however. In the case of a blazars, it appears a black hole
is involved. Anchoring an active galaxy, a supermassive black hole draws gas
inward. Some is swallowed, yet some is simply accelerated and then ejected in
high-speed jets along the galaxy's axis of rotation. Intense, twisted magnetic
fields may play a role.
Some ultra high-energy cosmic rays might originate in blazar jets, Piner told
SPACE.com. But other phenomena may serve as particle accelerators in
space, such as merging galaxies or colliding black holes.
Piner and his colleagues observed three blazars, known from previous observations
to be super speedy, using the National Science Foundation's Very Long Baseline
Array radio observatory.
The results confirm the previous work and pin down the speeds with greater
accuracy. The phenomenal pace of the plasma blobs looks to have reached a limit.
"All the results from blazar jet observations are in agreement with Einstein's
Theory of Special Relativity," Piner said. "The jets are accelerated right up
to the edge of the speed-of-light barrier but not beyond, even though these
are some of the most efficient accelerators in the universe."
Other articles from last week's AAS meeting:
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