Gravitational astronomy
Gravity is one of the fundamental forces of nature. It is the force which keeps small and large scale systems bound, and functioning in equilibrium. By observing at gravity waves astronomers can “see” what is going on in the non-electromagnetic universe.
Gravity waves are fluctuations in the strength of gravitational fields, caused by oscillations in spacetime. These oscillations are mostly caused by large objects of astronomical mass pulsing in shape or quickly moving back and forth. That pulse is then sent off into space, gradually loosing strength. Any object in the path of the wave will feel in increase in strength in the gravitational field as the wave passes.
While technically not correct, conceptually, it’s easier to think of gravity waves as a type of sound wave passing through space at the speed of light.
There are two main problems when observing gravitational waves:
To be able to measure these incredibly weak waves, an equally incredibly sensitive instrument needs to be used. An example of this is the Laser Interferometer Gravity Wave Detector used at the Australian International Gravity Observatory in Gingin. The detector works by using lasers and sapphire optics to create a resonance, to build up the strength of the beam. Due to the incredibly sensitive alignment of the apparatus any form of movement causes the beam to stop reflecting and transmit. This transmission is recorded as a possible gravity wave. To ensure that this is not a local product (e.g. earthquake or explosion), there are multiple observatories around the world which are linked. A gravity wave will be felt by all of the observatories, with a slight offset depending on which direction it came from. To avoid false readings the observatories need to be placed in sites where there is no significant seismic activity.
Due to the constant search for the perfect gravity wave detector, there have been a number of scientific spin-offs which can be used in other areas. These include; Radar Oscillators which help detect previously undetectable aircraft, like the Stealth Bomber, and identify areas of turbulence; Superconducting Gravity Gradiometers, which allows for more rapid airborne ore detection survey, and; Coastal Ocean Wave Monitors, which provide an accurate land-based early detection system for potentially harmful waves.
Despite all of the gravity astronomers’ best efforts over the last 40 years, there have been no confirmed detection of gravity waves to date. The indirect effects of gravity waves have been seen in observations of a binary pulsar system – an observation which won the astronomers a Nobel Prize in 1993.
Gravity waves are fluctuations in the strength of gravitational fields, caused by oscillations in spacetime. These oscillations are mostly caused by large objects of astronomical mass pulsing in shape or quickly moving back and forth. That pulse is then sent off into space, gradually loosing strength. Any object in the path of the wave will feel in increase in strength in the gravitational field as the wave passes.
While technically not correct, conceptually, it’s easier to think of gravity waves as a type of sound wave passing through space at the speed of light.
There are two main problems when observing gravitational waves:
- The strength of a gravity wave is much weaker than that of an electromagnetic wave (around 1038 times in fact!), and
- Gravitational waves interact with each other, unlike electromagnetic waves which need matter to interact.
To be able to measure these incredibly weak waves, an equally incredibly sensitive instrument needs to be used. An example of this is the Laser Interferometer Gravity Wave Detector used at the Australian International Gravity Observatory in Gingin. The detector works by using lasers and sapphire optics to create a resonance, to build up the strength of the beam. Due to the incredibly sensitive alignment of the apparatus any form of movement causes the beam to stop reflecting and transmit. This transmission is recorded as a possible gravity wave. To ensure that this is not a local product (e.g. earthquake or explosion), there are multiple observatories around the world which are linked. A gravity wave will be felt by all of the observatories, with a slight offset depending on which direction it came from. To avoid false readings the observatories need to be placed in sites where there is no significant seismic activity.
Due to the constant search for the perfect gravity wave detector, there have been a number of scientific spin-offs which can be used in other areas. These include; Radar Oscillators which help detect previously undetectable aircraft, like the Stealth Bomber, and identify areas of turbulence; Superconducting Gravity Gradiometers, which allows for more rapid airborne ore detection survey, and; Coastal Ocean Wave Monitors, which provide an accurate land-based early detection system for potentially harmful waves.
Despite all of the gravity astronomers’ best efforts over the last 40 years, there have been no confirmed detection of gravity waves to date. The indirect effects of gravity waves have been seen in observations of a binary pulsar system – an observation which won the astronomers a Nobel Prize in 1993.