Gravitational wave-detecting satellite LISA Pathfinder launch postponed

The launch of an experimental satellite that will test a technique to detect ripples in space and across time has been postponed.

From a vantage point 1.5 million kilometres (930,000miles)fromEarth, the European-built spacecraft, known as LISA Pathfinder,is expected to break ground in the search for the ripples, knownas gravitational waves, caused by fast-moving, massive celestialobjects such as merging black holes.

It was originally scheduled to launch at 0415 GMTWednesday (11:15 p.m. ET) from the European Space Agency'sKourou, French Guiana, launch site.

But less than 12 hours before launch, ESA reported a problem with the Vega rocket carrying the satellite. That problem requires further investigation. Depending on the results of the investigation, the launch could go ahead on Dec. 3, ESA said.

Scientists have high hopes for the satellite once it launches.

At a news conference prior to the launch delay,European Space Agency deputymission scientist OliverJennrich said the LISA Pathfinder "will really open up a new window into the universe.God knows what we will learn."

Like light, gravity travels in waves. Unlike light,gravitational waves bend the interwoven fabric of space and
time, a phenomenon conceptualized by physicist Albert Einstein acentury ago. Before Einstein's general theory of relativity,gravity was seen as a force between two bodies.

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In the pre-Einstein view of physics, if the sun disappearedone day, people on Earth would feel it instantly. In Einstein'sview, the effects would not be felt for eight minutes, the timeboth light waves and gravitational waves take to travel from thesun to Earth.

So far, attempts to detect gravitational waves usingEarth-based detectors have been unsuccessful.

Massive objects such as black holes bend space and time morethan smaller bodies like the sun, similar to how a bowling ballwarps the surface of a trampoline more than a baseball.

"There's a whole spectrum of gravitational waves, just likethere's a whole spectrum of electromagnetic waves," said
astrophysicist Ira Thorpe of NASA's Goddard Space Flight Center.

Like a buoy rising and falling on theocean

An operational gravitational wave observatory underdevelopment would require three satellites, flying in a triangle
formation about 1 millionkilometres (621,000 miles)apart. Thesatellites would contain small metal cubes that would oscillateas a gravitational wave passes through, similar to a buoy risingand falling on the ocean.

Using a laser to measure tiny changes in distance betweenthe cubes, scientists hope to track the subtle flexing of spaceand time. LISA (Evolved Laser Interferometer Space Antenna)Pathfinder will demonstrate the concept with two metal cubes 38 centimetres (15inches) apart inside a single spacecraft.

The mission, designed to last six months, cost about400millioneuros ($568 million Cdn).