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  • 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.

Hunting down gravitational waves is one of the most challenging engineering endeavors


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