The Warped Side of the Universe
Kip's interview with Annalie touched on many topics, from black holes to cosmology. All are fundamentally related by Einstein's picture that gravity should be described by the warping of time and space. Astronomers have discovered more and more examples of this warping, and Einstein's vision of gravity has become central to modern physics.
Astronomers use warped space-time to describe the universe they see, and theoretical physicists are trying to modify or extend Einstein's picture in order to make it consistent with their quantum description of the way that elementary particles behave. Front-line research therefore both uses the theory to explain what it can explain, and looks for the first cracks in the theory, where there are phenomena it can't explain.
There are many resources if you want to find out more about what Kip talked about. There are some good websites giving simple explanations of many aspects of general relativity, such as Einstein Online. In Wikipedia you can find excellent individual articles on all the subjects Kip discussed. Here are some pointers:
- For the way gravity affects clocks near the Earth, see the discussion of the GPS navigation system in Wikipedia.
- For how warped time and space make a black hole, listen to Annalie's interview with Clifford Will, and then take in the other interviews, which tell you how modern astronomers and physicists are investigating black holes.
- For cosmic strings, see this website at Cambridge University.
- How accurate is Einstein's description of gravity? Why do astronomers trust it, and why at the same time are they looking for flaws in it? These questions come up in Annalie's interviews with Clifford Will and with Jürgen Renn.
- Running through the whole interview is the idea of gravitational waves. The search for gravitational waves is a major activity in the world-wide scientific community.
A world-wide network searching for gravitational waves
Gravitational wave astronomy, the study of black holes, neutron stars and other energetic objects in space using gravitational waves, can only be done within a world-wide network, where many scientists and organisations contribute to the common goal.
Earthbound gravitational wave detectors have been under development since the 1960's, but the current generation of detectors is the first to have a real chance of making detections. The instruments are periodically upgraded, and the first detection is just a matter of time. In the USA the detector project is called LIGO; in Italy it is VIRGO; in Germany it is GEO, in Japan it is LCGT, and in Australia AIGO. These projects work closely together, and include scientists from many other countries as well, such as the UK, France, the Netherlands, Spain, Australia, India, Hungary, Russia, and many more. The international LIGO Scientific Collaboration (which includes GEO) and the VIRGO collaboration together involve more than 800 scientists.
Members of the general public can participate in the analysis of the data from the LIGO, GEO, and VIRGO detectors by downloading the screen-saver of Einstein@Home, which does data analysis on laptops and home computers when they are idle. This is a great way of staying in touch with the latest developments in this exciting field. Annalie's interview with Badri Krishnan explores the challenges of searching gravitational wave data for the very weak signals that are expected.
The world-wide gravitational wave scientific community is also planning and preparing a space-based gravitational wave detector called LISA. It will be one of the biggest space missions ever devised: LISA will search for gravitational waves using three satellites and laser beams 5 million kilometers long. When LISA goes operational, it will paint us an entirely new picture of the universe. Annalie's interview with Joan Centrella talks about LISA.
More on LISA here:
If you want some good books that link all this together, check out Einstein Online's recommended lists of non-mathematical books (including Kip's book) or books that use high-school mathematics (including one by Bernard Schutz).