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.