The Very Large Telescoping Interferometer firing it’s adaptive optics laser. Image Credit: ESO/G. Hüdepohl
And according to a new study by Robert Nemiroff, a physics professor at Michigan Technological University (and co-creator of Astronomy Picture of the Day), this phenomena may help shine a light (no pun!) on the cosmos, helping us to map it with greater efficiency.
Consider the following scenario: if a laser is swept across a distant object – in this case, the Moon – the spot of laser light will move across the object at a speed greater than c. Basically, the collection of photons are accelerated past the speed of light as the spot traverses both the surface and depth of the object.
The resulting “photonic boom” occurs in the form of a flash, which is seen by the observer when the speed of the light drops from superluminal to below the speed of light. It is made possible by the fact that the spots contain no mass, thereby not violating the fundamental laws of Special Relativity.
An image of NGC 2261 (aka. Hubble’s Variable Nebula) by the Hubble space telescope. Image Credit: HST/NASA/JPL.
At a meeting of the American Astronomical Society in Seattle, Washington earlier this month, Nemiroff shared how these effects could be used to study the universe.
“Photonic booms happen around us quite frequently,” said Nemiroff in a press release, “but they are always too brief to notice. Out in the cosmos they last long enough to notice — but nobody has thought to look for them!”
Superluminal sweeps, he claims, could be used to reveal information on the 3-dimensional geometry and distance of stellar bodies like nearby planets, passing asteroids, and distant objects illuminated by pulsars. The key is finding ways to generate them or observe them accurately.
For the purposes of his study, Nemiroff considered two example scenarios. The first involved a beam being swept across a scattering spherical object – i.e. spots of light moving across the Moon and pulsar companions. In the second, the beam is swept across a “scattering planar wall or linear filament” – in this case, Hubble’s Variable Nebula.
Photonic booms caused by laser sweeps could offer a new imaging technique for mapping out passing asteroids. Credit: P. Carril / ESA
This sort of imaging technique is fundamentally different from direct observations (which relies on lens photography), radar, and conventional lidar. It is also distinct from Cherenkov radiation – electromagnetic radiation emitted when charged particles pass through a medium at a speed greater than the speed of light in that medium. A case in point is the blue glow emitted by an underwater nuclear reactor.
Combined with the other approaches, it could allow scientists to gain a more complete picture of objects in our Solar System, and even distant cosmological bodies.
Nemiroff’s study accepted for publication by the Publications of the Astronomical Society of Australia, with a preliminary version available online at arXiv Astrophysics
Further reading:
Michigan Tech press release
Robert Nemiroff/Michigan Tech
About Matt Williams
Author, freelance writer, educator, Taekwon-Do instructor, and loving hubby, son and Island boy!- FASHION WEEK - USA Fashion and Music News
- GOOGLE NEWS - Google News Blogger
- PINTEREST ACROSS THE UNIVERSE - Google Images Nasa Images
- LAST FM - Download Music Legally Direct From Artist
- WOMEN COMMUNITY - Women Communty Photography Videos Beauty
- DISNEY CHANNEL - Photos and Music News
- BABY JUSTIN BIEBER - Google Images Google News
- LADY GAGA - Google Images Google News
- ACROSS THE UNIVERSE - Google Images Universe Pictures
- VICTORIA´S SECRET COMMUNITY - Victoria´s Secret Fashion Show Photos
No comments:
Post a Comment