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This 'disco ball' is the densest object orbiting the solar system

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Called LARES, this tiny — but remarkably heavy — satellite both looks and acts like a disco ball. By bouncing lasers off its reflectors, Italian researchers are hoping to prove Einstein’s conjecture that the Earth warps space-time as it rotates.

One important aspect of general relativity is an effect called rotational-frame dragging, or the Lense-Thirring effect. Einstein said that the rotation of a sufficiently massive object would distort space and time, thus dragging a nearby object out of position (a phenomenon known as precess) in a way that would overrule the much simpler math posited by classical Newtonian physics.


But capturing the effects of rotational-frame dragging has proven exceedingly difficult; the effect is incredibly minute — about one part in a few trillion. The only way to measure it is to look at something massive, like a black hole, or create a super sensitive device and put it into orbit.

And this is exactly what ESA scientists Antonio Paolozzi and Ignazio Ciufolini have done by virtue of LARES, the Laser Relativity Satellite. It’s a soccer ball-sized tungsten sphere with no thrusters or electronic components. LARES is covered with 92 reflectors which will allow it to be tracked by lasers on Earth.


Now, despite its small size, this thing weighs 882 pounds (400 kg). And in fact, it’s the first aerospace structure ever made from tungsten alloy — and it’s the densest object orbiting anything in the solar system. Its mass, therefore, should create the noticeable precess effect the scientists are looking for. By tracking LARES’s position with the lasers, and then carefully measuring how it moves, the scientists are hoping to see evidence of frame-dragging.


And to compensate for other potential effects, measurements will be supplemented with those from the LAGEO and LAGEO 2 satellites, two other reflective satellites launched earlier.

LARES was launched into space on February 13th, 2012.

Check out the entire report: “LARES successfully launched in orbit: satellite and mission description.”


Top image: ESA; frame-dragging graphic Annie Rosen.