What Does the Future Hold?

Dr. Michael Muno continues his discussion in part II of his blog.
While focused on the present, Mike Muno, an astrophysicist at Caltech, has thoughts about where he would like to see his research go in the future. In this post, he discusses what he hopes to be studying with X-rays in the upcoming years.

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The future holds several planned and proposed observatories that I am keen on using. In the medium term, I plan to work with data from an innovative X-ray telescope that will be one of the first to produce focused images in harder X-rays. That instrument, HREF="http://www.nustar.caltech.edu/>the Nuclear Spectroscopic
Telescope Array (NuSTAR) is scheduled to launch in 2011. I am interested in NuSTAR because it will be much more sensitive to faint, hard X-ray sources than previous observatories, and should reveal scores of new examples of accreting black holes and neutron stars. The telescope will also measure the amount of titanium formed in supernova explosions, which will provide crucial information about how a star explodes. Titanium forms in supernovae at the boundary between the matter that is ejected, and that which remains behind to form a black hole or a neutron star. The amount of titanium formed reveals a lot about how light, neutrinos, and atoms interact during the turbulent process of a stellar explosion.

Beyond Chandra and NuSTAR, my main interest is in observatories that can map the space-time around neutron stars and black holes. This requires much larger telescopes than we have launched previously. One approach is to split the X-ray signal up finely in energy, so we can look for signals at energies characteristic to individual atoms. Once the atoms are identified, we can determine how the energy of the light decreased as it escaped from the enormous gravitational potential of the black hole or neutron star.

This, using the laws of general relativity, would allow us to determine the mass and radius of the inner region around the black hole or neutron star. If we can obtain even more photons, we can look at their arrival times in fine detail, and extend our knowledge even further. We might be able to see matter near the event horizon of a black hole ringing at characteristic frequencies, which would tell us the structure of space-time there. Or, we could search for similar signals from matter on the surfaces of neutron stars that would tell us what the matter in its interior is made of (neutrons, individual quarks, or something else?).

Such studies are needed to make progress at the frontiers of physics. The two main theories are general relativity for gravity, the standard model (composed of several quantum theories) describing the properties of fundamental partials like quarks and electrons. The major theories in physics that we use to describe the natural world can all predict nearly every phenomenon we have ever observed in the laboratory. Yet, we know they must be "wrong" at some level. For instance, quantum mechanics and general relativity describe space and time so differently that there is no way that they can both describe fundamental particles. Fortunately, black holes and neutron stars test the extremes of both of these theories, and so observations of them might provide the clue that is needed to find a unified description of gravity and quantum theories. I am hoping to be on the forefront of this research, using the next generations of X-ray observatories.

-Mike Muno
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(Part I: "Finding Answers to Big Questions" http://chandra.harvard.edu/blog/node/40)