Tuesday, January 31, 2012

Getting physical

I haven't posted recently on matters of physics and space travel. In hindsight ... I surprise myself. Because these are (related) topics of great personal interest.

In view of recent do-they-or-don't-they reports of neutrinos slightly outpacing photons -- i.e., a possible chink in the century-old edifice that is Einsteinian relativity -- here's another reminder that Einstein tended to get things right. To wit: It's been shown (again) that the rotation of a massive object produces frame dragging of space-time, as predicted by general relativity.

After the very elaborate Gravity Probe B (GP-B) experiment, decades in the making, this subtle effect has been independently remeasured. (Decades: That puts my few months delay in commenting into perspective.) From the American Physical Society, see "Viewpoint: Finally, results from Gravity Probe B." Fascinating stuff.

But wait! There's more!

NASA began the new year by putting two probes into lunar orbit. Working in tandem, the Gravity Recovery And Interior Laboratory (GRAIL) probes, A and B, will reveal details of lunar composition all the way down to the moon's very core. See "NASA marks 2012 with twin probes in moon orbit."

Grail A and B
Like GP-B, the GRAIL experiment relies on subtle effects. In the GRAIL case, the experiment tracks tiny changes in the distance between the twin probes -- subtly altered in real-time as each passes over slight inhomogeneities in the moon. After lots of math, tiny changes in separation between the probes across many orbits will yield 3-D maps of the lunar interior.

That's one past and one present neat NASA mission. What might we see in the future? To guess about that, consider where NASA is investing some of its long-range funds: "NASA Picks 3 Pioneering Technologies for Deep Space Travel." See the article for details, but the short form is: a scaled-up light-sail trial, an improved atomic clock (valuable for navigation), and lasers -- rather than radios -- for deep-space communications. Any and all could contribute to a major revolution in deep-space mission design.

Pluto Kuiper Express
Missions with that new tech should start flying about 2015 -- around the time New Horizons Pluto Kuiper Belt Flyby mission gives us our first close look at Pluto, before proceeding deeper into the Kuiper Belt. Sounds long-range to me ...

Stay tuned.

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