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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.
Don't think it is a slow news day around here. Because apparently there are another 10^45 articles prepped and queued for auto-publish this morning about other critical batches of photons we've got to know about.
It's a trans-NEPTUNIAN object. Not trans-NEPTUNIUM. Neptunium is an element (Np. Atomic Number 93).
You'll have to file the case on Pluto, though. Feel free to take as many lawyers as you can.
But what about Uranus?
"I appreciate that "dwarf" planet doesn't sound too PC but I do wonder whether we should reserve the adjective "tiny" for items too small for their own gravitational mass to pull them into a sphere."
If you're going to invent your own classification system, then I propose we make everyone feel better by classififying them as follows:
'Tall' - A body too small to form a sphere.
'Grande' - Forms a sphere but does not clear its orbit.
'Venti' - Clears its orbit.
'Trenta' - Gas giants.
The "largest small planet" should more likely be the Earth. Certainly the discrepancy between Earth and ANY of the Jovians is huge, and the Jovians are very different beasts. Even the least massive (Uranus) is 15x greater than Earth (and Jupiter is more massive than every other planet combined).
"Transparent" is a shit show that trades on every stereotype going. A man in drag is NOT a transsexual.
I'm disappointed. I scrolled the rest of the comments and didn't find any more top posts from Moblaster. I mean, after the second or third post it was obvious what he was up to -- one post for every photon.
I come here for the love
Why all this insistence on mechanisms involving an atmosphere? X-ray tubes don't require gas.
You get X-rays whenever you abruptly stop or deflect a fast enough charged particle (such as an electron). Pluto is a ("dwarf") PLANET, with no (known) planetary magnetic field to deflect the solar wind or cosmic radiation. Such a BIG solid body, even 'way out there from the sun, should be stopping LOTS of charged particles all the time.
(Sure, charged particles stop more "abruptly", and thus release more energetic photons, when hitting heavy atoms rather than things like hydrogen. But some of the incoming stuff will be fast enough to emit x-rays even when slamming into the bare photon of a hydrogen nucleus. And then there's the inverse case when an incoming heavy nucleus from cosmic radiation hits an electron.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
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?
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
"That's a lot of photons emitted by the planet, isn't it?"
Avogadro's number is only about 6*10^23, so we're talking something like ten thousand gram-moles of x-rays emitted during the observation period.
Ten Thousand Gram Moles of x-ray photons? Yike!
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
> it is a good thing for pluto's sake that public schools have no money
> for new textbooks, the ones here are from the 90s at best when pluto
> was still a respected ninth planet of our little corner of the universe.
Actually, Pluto's "planetary status" has been suspect since just after its discovery. Here's an article featuring a snippet from 1934 (YES!)... http://blog.modernmechanix.com...
> So that Pluto ranks as the largest asteroid, rather than the smallest
> planet; and it may be necessary to look farther for unknown planets.
I'm not repeating myself
I'm an X window user; I'm an ex-Windows user
Can you please convert that to Olympic swimming pools or football fields? I am american. Thanks!
So am I. Let's see...
10,000 gram moles of x-ray photons...
Take 22 pounds of hydrogen. Turn each atom of hydrogen into an x-ray photon.
Hydrogen bombs do something like that... But let's use total annihilation because the numbers are easier to find.
1 gm of antimatter + 1 gm of matter -> 43 kilotons of TNT equivalent. So call it 21.5 kilotons per gram.
Energy equivalent of a proton's mass is really close to 1 GEv. We don't know what energy x-rays they were detecting, so let's use the energy of photons from a typical dental x-ray machine: 70 kEv. So 10^4 * 7*10^4 / 10^9 = 0.7 grams of energy, or about 15 kilotons of TNT-equivalent emitted per measurement interval.
The Hiroshima bomb was estimated at 15 kilotons, Nagasaki at 20. So call it "Almost exactly one Hiroshima bomb" or "3/4 of one Nagasaki bomb" of x-ray energy released during the observation interval.
(Or maybe boost it up a bit, because I assumed perfect efficiency for the x-ray telescope's mirrors and detector, which I suspect is quite optimistic.)
How's that?
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way