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Telescopes and space missions

Telescopes and space missions

Flash Physics: NASA and FEMA conduct asteroid-impact exercises, tiny lasers for microscopy, NSF reviews its Arecibo and Green Bank funding

07 Nov 2016 Tushna Commissariat

Flash Physics is our daily pick of the latest need-to-know developments from the global physics community selected by Physics World's team of editors and reporters

Collision course? Illustration of a near-Earth object

“Asteroid-impact emergency-planning” exercises held by NASA and FEMA

“What would we do if we discovered a large asteroid on course to impact Earth?” That was the scenario being discussed at a recent joint meeting – held by NASA and the Federal Emergency Management Agency (FEMA) – in El Segundo, California. The third in a series of meetings, the two agencies aim to develop and design a way to respond in case of an asteroid impact. “It’s not a matter of if – but when – we will deal with such a situation,” says Thomas Zurbuchen, the recently appointed associate administrator for NASA’s science-mission directorate. “But unlike any other time in our history, we now have the ability to respond to an impact threat through continued observations, predictions, response planning and mitigation.” According to the agencies, exercises such as this one allow the planetary-science community to show how it would collect, analyse and share data about a hypothetical asteroid predicted to impact Earth, while giving emergency managers a chance to discuss how that data would be used to prepare and respond to the threat, as well as warn the public. “It is critical to exercise these kinds of low-probability but high-consequence disaster scenarios,” says FEMA administrator Craig Fugate. “By working through our emergency-response plans now, we will be better prepared if and when we need to respond to such an event.” The scenario simulated during this exercise involved a hypothetical possible impact four years from now – a fictitious asteroid imagined to have been recently discovered, with a 2% probability of impact with the Earth on 20 September 2020. While mounting a deflection mission to move the asteroid off its collision course has been previously simulated, this particular exercise was designed so that the time to impact was too short for a deflection mission to be feasible – and so to pose a great future challenge to emergency managers faced with a mass evacuation of large metropolitan areas. You can read more about these planning exercise’s on NASA’s Planetary Defense portal.

Tiny lasers could boost microscopy

A new microscopy technique that uses micron-sized lasers to illuminate objects from within has been created by researchers in the US and Slovenia. Seok Hyun Yun and colleagues at Harvard University, Massachusetts Institute of Technology and the J Stefan institute in Ljubljana have shown that perovskite nanowires (about 5 μm long and 400 nm thick) can be pumped by a green laser so that they emit their own red laser light. They also created a microscopy system that uses a spectrometer to obtain images using only the laser light emitted by the nanowires. The system could be used to create high-resolution images of biological samples by having cells or tissue absorb the nanowires. This is similar to fluorescence microscopy, which involves adding a fluorescent dye to samples – but Yun and colleagues say the nanowires could offer several advantages over fluorescence microscopy, including superior depth resolution. The nanowires are described in Physical Review Letters and could also be engineered to emit different coloured light, depending on their local chemical environments.

NSF reviewing its funding for Arecibo and Green Bank observatories

The National Science Foundation in the US is currently in the process of determining its future level of funding for a bunch of astronomical facilities, mainly the Arecibo Observatory in Puerto Rico and the Green Bank Telescope in West Virginia, US. In reviews carried out over the past decade or longer, both observatories were identified as candidates for funding reductions, largely due to budget constraints that force the NSF to be able to fund other facilities that are thought of as more integral to achieving current astronomy and space-science goals. The NSF is currently carrying out an Environmental Impact Statement (EIS) process to decide both observatories’ fate, before they choose to either make no changes, ramp down funding or “potentially mothball or deconstruct each”. The process began in May for Arecibo and in October for Green Bank, before a final decision will be reached within the next year and a half. Despite various recommendations for reduced funding for Arecibo, Patrick Taylor, group lead for planetary radar at Arecibo, has warned the NSF that “any level of divestment by the NSF of Arecibo, without replacement of that funding from some source, will endanger the NASA-supported work that we do, which is also congressionally mandated, of tracking and characterizing potentially hazardous asteroids.”

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