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Pluto Is Emitting X-Rays (digitaltrends.com)
An anonymous reader quotes a report from Digital Trends: Scientists have noticed the tiny trans-Neptunium object emitting X-rays, which, if it is confirmed, is both a baffling and exciting discovery. Carey Lisse and Ralph McNutt from Johns Hopkins University Applied Physics Laboratory and a team of colleagues detected the X-rays by pointing the Chandra X-Ray Obervatory telescope in Pluto's direction four different times between February 2014 and August 2015. Seven photons of X-ray light were detected during these observations, confirming the team's hypothesis that the dwarf planet is detectable on the X-ray spectrum, potentially due to the presence of an atmosphere. Their findings have been published in the scientific journal Icarus. Why is this such a big deal? First of all, it would challenge what scientists have previously believed to be true of Pluto's nature. Until now, the popular description of the dwarf planet is as a tiny ball of frozen rock slowly meandering around the sun some 3.6-billion miles away. One of the possible explanations for why Pluto is emanating X-rays would be that the high energy particles emitted by the sun are stripping away and reacting with Pluto's atmosphere, producing the X-rays that are visible to Chandra. There are other potential explanations, such as haze particles in Pluto's atmosphere scattering the sun's X-rays are possible, though unlikely given the temperature of the X-rays observed. It is also possible that these X-rays are actually bright auroras produced by the atmosphere, but that would require Pluto to have a magnetic field -- something that would have been detected during New Horizon's flyby, yet no evidence of one was found.
It's a trans-NEPTUNIAN object. Not trans-NEPTUNIUM. Neptunium is an element (Np. Atomic Number 93).
Seriously? You woke me up to read about seven photons from across the other side of the solar system?
How big is the detector? How far is it from Pluto?
They detected them from the Chandra X-ray Observatory, which is in orbit around the Earth. That puts the distance between the detector and Pluto at somewhere between 29 and 50 astronomical units of about 93 million miles each, depending on where the Earth and Pluto were in their orbits during the observations.
- Calculate the area of a sphere of that radius. (That's about 10^20 square miles at the low end, abut three times that at the high end.)
- Divide by the aperture of the x-ray telescope (0.43 sq ft), in square miles. (i.e. multiply by 1.3*10^7.) We're now in the 10^27 order of magnitude.
- Assume the x-rays are ONLY the result of solar wind bombardment? Divide by two. (You'd have to do that more than three times to drop the number by even ONE order of magnitude.)
- Multiply by seven photons detected.
That's a lot of photons emitted by the planet, isn't it?
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