spaceSpace and Physics

Hunt For Gravitational Waves Continues With New Spacecraft


Jonathan O'Callaghan

Senior Staff Writer

4194 Hunt For Gravitational Waves Continues With New Spacecraft
LISA Pathfinder launched yesterday (shown). ESA–Stephane Corvaja, 2015

Yesterday, the European Space Agency’s (ESA) LISA Pathfinder spacecraft launched, on a mission that could one day lead to the discovery of elusive gravitational waves. But while that’s obviously exciting, it’s how this spacecraft will be doing it that will blow your mind.

The launch took place from ESA’s spaceport in Kourou, French Guiana, on top of a Vega rocket. On board, the spacecraft has technology that will be used to demonstrate how to find gravitational waves. It won’t actually be able to make a direct detection on this mission, but that in itself shows how keen scientists are to make a detection of gravitational waves.


Gravitational waves are believed to be ripples in space-time caused by massive objects such as interacting black holes, first theorized by Einstein. Despite numerous experiments over the last few decades, however, no detection has been made.

“Gravitational waves are the next frontier for astronomers,” said Alvaro Giménez Cañete, ESA’s Director of Science and Robotic Exploration, in a statement. “We have been looking at the universe in visible light for millennia and across the whole electromagnetic spectrum in just the past century. But by testing the predictions made by Einstein one hundred years ago with LISA Pathfinder, we are paving the road towards a fundamentally new window on the universe.”

The incredible technology on board LISA Pathfinder is remarkably simple. It has a pair of identical gold-platinum cubes measuring 4.4 centimeters (1.7 inches) across, separated by 38 centimeters (15 inches). Positioned 1.5 million kilometers (1 million miles) from Earth, the cubes will be subjected to no other forces aside from gravity.

The cubes will be in free-fall inside the spacecraft, touching nothing. The spacecraft will fire its thrusters 10 times a second to keep the cubes under the influence of gravity alone, and a laser system will then monitor the distance between the cubes, with an accuracy down to the diameter of an atom. It’s sort of like cupping your hands around a bubble and not letting it touch your skin.


The technology employed on LISA Pathfinder is simply incredible. ESA

“Scaled up, it is like tracking the distance between the tops of London's Shard skyscraper and New York's One World Trade Center, and noticing any changes down to just fractions of the width of a human hair,” Jonathan Amos writes for the BBC.

Proving the technology works will allow for a larger mission in the 2030s to be launched, which will use a similar method to try to detect ripples in gravity, caused by gravitational waves, from massive events in the universe such as merging galaxies. The detection of gravitational waves could even help us understand the characteristics of the event they originated from.

The spacecraft, which cost at least €450 million ($490 million, £325 million) to build, will begin six months of operations in March 2016. If it works, future detection of gravitational waves in space may be on the horizon.


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