14 DAY TRIAL // At this point, spacecraft exploring other worlds, or moving outside the solar system, figure out where they are in space by using Global Positioning System (GPS) satellites. But a team of experts proposes replacing this method with a pulsar-based reference system.
Such an approach would entail the same level of precision that is currently available using GPS, only more widespread and more immediate. That is to say, spacecraft moving in interstellar space would find it easier to use pulsars for reference than beam a signal back to Earth and waiting for a reply.
In order to understand how pulsars work, it is critical to first understand what they are. A pulsar is a special type of neutron star, which itself is the collapsed core of a former massive star. The progenitor stars have insufficient masses to create black holes upon collapse.
As such, they produce neutron stars. These objects are about 20 miles (32 kilometers) wide, but a single tablespoon of matter from their surface weighs about 100 trillion tons, the equivalent of an entire mountain here on Earth. Matter contained within is extremely compressed.
Pulsars differ from normal neutron stars only through the fact that their radiation jets are oriented towards Earth. As they spin, these radiations – usually in the X-ray portion of the electromagnetic spectrum – appear as if they were produced by a lighthouse; the star appears to be pulsating.
These pulses occur at extremely regular intervals, with precision levels comparable to those of atomic clock aboard GPS satellites. As such, they could hypothetically be used as standard location beacons, in reference to which spacecraft may establish their position.
This would be done in a rather straightforward mechanism – the probe would measure distant radiation pulses, and then cross-reference their arrival times with predicted values for a certain reference location. The latter could be Earth, the Sun, or some other star.
In other words, the spacecraft would contain a set of values that would be cross-referenced with observed pulsar radiation arrival time values. The difference would be used to calculate the spacecraft's exact position in respect to the nearest reference location, SpaceRef reports.
Investigators predict that the new system could achieve an accuracy level of about 5 kilometers (3.1 miles), which is extremely precise for space probes flying at tremendous speeds. This method would be about 8 times more precise than existing approaches.