Subtitles section Play video
-
Hunting down gravitational waves is one of the most challenging engineering endeavors
-
of the 21st century -- and now physicists are planning on launching that hunt into space!
-
Hello!
-
I'm Ian O'Neill, space producer for Discovery News, and I'm here to quickly talk about
-
another nugget of gravitational wave coolness.
-
If you're familiar with my videos on Discovery News, you'll know that I LOVE gravitational
-
waves, or more precisely, I LOVE the prospect of gravitational wave astronomy.
-
Gravitational waves are basically ripples in spacetime.
-
Imagine the ripples across the surface of a pond after dropping a pebble in the water
-
-- these ripples carry energy away from the *plop* in the surface.
-
If we wanted to, we could analyze the amplitude, speed and direction of these ripples to determine
-
the mass of the pebble that fell in and gain some useful information about the water they're
-
propagating through.
-
This model is quite useful for us to imagine how gravitational waves work; if we could
-
detect and measure them, we could reveal some incredible science about the objects creating
-
the spacetime ripples.
-
Gravitational waves were first theorized by Einstein nearly 100 years ago.
-
We have strong indirect evidence that they're out there, but directly detecting them has
-
been very difficult.
-
However we're slowly closing in.
-
As I've explained in a previous video, the US-based Laser Interferometer Gravitational-Wave
-
Observatory (LIGO) detector has recently been upgraded to begin the most precise search
-
for gravitational waves ever.
-
There are high hopes that through new noise-reduction and laser techniques that gravitational waves
-
will not only be identified, but will also be used to see energetic events such as black
-
hole and neutron star collisions, supernovas and, potentially, the effects of dark matter.
-
Basically, once this is achieved, the era of gravitational wave astronomy will have
-
begun.
-
But there's an even more advanced detector planned that could revolutionize our view
-
of the cosmos, and it involves sending a gravitational wave detector into SPACE, far from all the
-
noise and commotion we have down here on Earth.
-
Europe's Evolved Laser Interferometer Space Antenna (eLISA) is tentatively scheduled to
-
be launched into Sun-orbit in 2034 and will consist of 3 spacecraft.
-
The 3 probes will form the points of a triangle spaced millions of miles apart, setting up
-
the mother of all laser interferometers.
-
Laser interferometry is perfect for measuring extremely tiny fluctuations in distance, a
-
necessity for detecting faint gravitational wave signals.
-
As eLISA will be in space, this detector will be even more sensitive to gravitational waves
-
than LIGO, revealing energetic events in far off galaxies.
-
But 2034 is a long time to wait -- why is it going to take this long to launch the next
-
big thing in the gravitational wave hunt?
-
In short, the technology isn't there yet and the final design of eLISA isn't close
-
to being finalized.
-
But later this year, the first component of eLISA will be launched to test some key technologies.
-
The European Space Agency is going to send a single probe called the LISA Pathfinder
-
to the Sun-Earth Lagrangian Point L1.
-
The L1 point is an island of gravitational stability located directly between the Sun
-
and Earth, where the gravity between them balances out.
-
It's approximately 1.5 million kilometers away where we have several probes and space
-
telescopes currently anchored.
-
The Pathfinder probe will have a scaled-down interferometer set up between two masses inside.
-
It will basically be a physics laboratory experiment to test how an interferometer will
-
function in the space environment.
-
Although it's not designed to seek out gravitational waves, this will be the seed of eLISA.
-
So 2034 may be a long way off, but if all goes to plan, LIGO would have already detected
-
gravitational waves by then and eLISA will be our new eye in space to weed out the weakest
-
gravitational wave signals from the deepest depths of our universe.
-
And LISA Pathfinder is the first stepping stone to this ultimate goal.
-
For more information about advanced LIGO, which has just gone online, check out my recent
-
video
-
Make sure you check out that video, there's a link in the description if you're on your
-
mobile device.
-
And let us know in the comments below about your thoughts on the quest to find gravitational
-
waves.
