If you want
to celebrate the universe’s birthday, you might need to add a few more candles
to the cake. (More than 20 million)
That is
because our universe is about twenty (20) million years older than thought,
according to the most accurate measurement yet made of the universe’s age.
because our universe is about twenty (20) million years older than thought,
according to the most accurate measurement yet made of the universe’s age.
The data are
the latest from the Wilkinson Microwave Anisotropy Probe (WMAP), a satellite
launched in 2001 that has been mapping what’s known as the cosmic microwave
background radiation. This “afterglow of creation” is believed to be
radiation emitted as matter began to cool 400,000 years after the big bang
created the universe.
the latest from the Wilkinson Microwave Anisotropy Probe (WMAP), a satellite
launched in 2001 that has been mapping what’s known as the cosmic microwave
background radiation. This “afterglow of creation” is believed to be
radiation emitted as matter began to cool 400,000 years after the big bang
created the universe.
The faint,
almost uniform radiation is coming from every direction in the sky, and it can
be picked up from billions of light-years away. By mapping the cosmic microwave
background, WMAP is literally creating a picture of the early years of the
cosmos.
almost uniform radiation is coming from every direction in the sky, and it can
be picked up from billions of light-years away. By mapping the cosmic microwave
background, WMAP is literally creating a picture of the early years of the
cosmos.
Hot and cold
spots in WMAP’s cosmic microwave background data compared with computer simulations.
spots in WMAP’s cosmic microwave background data compared with computer simulations.
Universe’s
Fingerprint?
Fingerprint?
With precise
enough measurements, scientists can detect slight variations in temperature in
this primordial light: hot and cold spots that eventually formed the seeds of
galaxies.
enough measurements, scientists can detect slight variations in temperature in
this primordial light: hot and cold spots that eventually formed the seeds of
galaxies.
By matching the size of the spots—as well as other WMAP data—to
hundreds of millions of mathematical models of the universe, researchers can
determine which model best matches reality.
hundreds of millions of mathematical models of the universe, researchers can
determine which model best matches reality.
“I like
to describe it as a fingerprint,” said study co-author Charles Bennett, an
astrophysicist at Johns Hopkins University in Baltimore, Maryland. “We can
make a bunch of computer simulations of universes that all look
different,” by inputting different values for the unknowns, such as the
exact age and the amount of dark matter.
to describe it as a fingerprint,” said study co-author Charles Bennett, an
astrophysicist at Johns Hopkins University in Baltimore, Maryland. “We can
make a bunch of computer simulations of universes that all look
different,” by inputting different values for the unknowns, such as the
exact age and the amount of dark matter.
“Then
we have a mug book of these simulations“—an astrophysical version of a
collection of mug shots used to help witnesses identify criminals—”and our
fingerprint, which is our map of the sky,” he said. “We just look to
see what matches, and we say, That’s what our universe looks like.”
we have a mug book of these simulations“—an astrophysical version of a
collection of mug shots used to help witnesses identify criminals—”and our
fingerprint, which is our map of the sky,” he said. “We just look to
see what matches, and we say, That’s what our universe looks like.”
Based on
seven years of WMAP data, Bennett and colleagues concluded that the universe is
13.75 billion years old, give or take 0.11 billion. Previous calculations using
the same methods but fewer data had said the universe is 13.73 billion years old,
give or take 0.12 billion. Twenty million years might seem short, in the grand
scheme of things. But the new, more tightly defined age will give scientists a
better shot at solving some of the great mysteries of the universe, such as
dark matter and dark energy.
seven years of WMAP data, Bennett and colleagues concluded that the universe is
13.75 billion years old, give or take 0.11 billion. Previous calculations using
the same methods but fewer data had said the universe is 13.73 billion years old,
give or take 0.12 billion. Twenty million years might seem short, in the grand
scheme of things. But the new, more tightly defined age will give scientists a
better shot at solving some of the great mysteries of the universe, such as
dark matter and dark energy.
“You
can’t just measure stuff and put together a model and say, Oh, that’s our
universe, and stop there,” Bennett said. “The big question is, as we
measure more carefully, does the model break or does it need something
else?“
can’t just measure stuff and put together a model and say, Oh, that’s our
universe, and stop there,” Bennett said. “The big question is, as we
measure more carefully, does the model break or does it need something
else?“
“By
squeezing down on the values of all these things [like the universe’s age] we
are squeezing down on other things, like dark energy. The better we know the
values of these things, the better we understand dark energy.“
squeezing down on the values of all these things [like the universe’s age] we
are squeezing down on other things, like dark energy. The better we know the
values of these things, the better we understand dark energy.“
The findings
are part of a suite of WMAP papers published online in January at the
scientific preprint Web site arXiv.org.
are part of a suite of WMAP papers published online in January at the
scientific preprint Web site arXiv.org.
(Via National Geographic)
