RWU Magazine - Fall 2013 / Issue #9 - page 6

On the Waterfront
RWU {Fall 2013}
6 Burning Questions on…
Gamma Ray
What, exactly, is a gamma ray burst?
In short, an exploding star. When a star runs
out of fuel, it collapses in on itself to form a
black hole and ejects jets of energy that
emanate from its poles. That energy emerges
in the form of light.
What does an exploding star look like?
Practically speaking, the naked eye can’t see
them. But a satellite positioned along a GRB
beam can detect them, and telescopes on
Earth can provide a closer view. For a few
moments, an exploding star will be the
brightest thing in the universe.
How often do stars die?
Astronomers detect only about two per week,
but thousands occur daily across billions of
galaxies. Most actually exploded 6 or 7
billion years ago or more – halfway across our
13.7-billion-year-old universe – but the light
is just reaching us now.
How did scientists discover
interstellar GRBs?
The Vela satellites, launched to monitor
adherence to the nuclear test ban treaty,
often detected random bursts of gamma rays
from space. In 1972, the U.S. declassified
that information for astronomers to decipher.
Theories abounded –
nuclear war between
alien races!
– but exploding stars emerged as
the consensus.
Does this happen in the Milky Way?
Some scientists theorize that a nearby GRB
may have caused the Ordovician extinction
event more than 400 million years ago.
Others may have occurred since, but without
the jets of energy aimed at the Earth directly.
Only a few stars in the Milky Way –
including our sun (whew!) – are large enough
for explosion to be likely.
Just in case – what would a nearby
GRB mean for humans?
If any nearby star that we can see in the sky
were to explode with its GRB pointing toward
Earth, it would mean catastrophe. That
concentration of gamma rays would boil off
the atmosphere. And with no atmosphere…
Well, you get the picture.
RWU {Fall 2013}
When Adria Updike’s iPhone buzzes, she acts fast – a satellite up in space may be texting her about a gamma ray burst,
and if she wants a clear view, she has only moments to reposition one in a series of telescopes across the globe. Updike, an
associate professor of physics at RWU, uses the gamma ray bursts (or GRBs) as probes into the outer limits of the universe:
“Turning on a GRB for a few minutes is like turning on a flashlight in a galaxy that we didn’t even know existed,” she says.
Here, she illuminates GRBs for the unenlightened.
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