Home/BlogLast night I took several hundred photos between 11:30 pm and 4 am trying to catch some Perseid meteors. I only got about 15 bright ones, so I’d say this was not a good year for the Perseids.
But almost every one started out with a blue-green trail as they burned up, for example this one near the Andromeda galaxy (the fuzzy area to the lower right, click image for full-size):
Perseid meteor near the Andromeda galaxy, August 13, 2015. Canon 6D with 16-35 f/4 lens wide open at 16mm, 30 sec exp, ISO800.
The blue-green color I’ve seen explained as copper or magnesium or iron or nickel, so I have no idea what to believe. Expert opinion welcome.
Hi Roy,
http://www.stevespanglerscience.com/lab/experiments/flame-test
Have a good day, Jerry
Last night @ 11 PM at the 45 N parallel traveling from East Northeast to South Southwest a meteor: a white ball of intense light with an immediate following thin white trail which evolved into a thick blue-green tail stretching across 3/4 of the sky. The meteor crossed across Polaris.
Is it possible to determine the speed and orbital parameters of the Perseids from the length and duration of the streaks? I get that the earth’s orbital speed is about 66 kmi/hr (29.5 km/s). I assume, since the Perseids are debris of a comet (Swift-Tuttle), that they are in highly elliptical orbits (first noted in 36AD), that they are approaching perihelion; and therefore that their orbital speed is much higher. Why isn’t there an image of the shower after they are past the sun – because it occurs in daylight hours?
Per Wikipedia, iron is heavy in green and blue emission lines. It is also plentiful (at least in the inner solar system).
https://en.wikipedia.org/wiki/Emission_spectrum
Roy
When out and watched it after midnight local time here and as you said fairly slow. Saw one though that was unusual: fairly bright but traveling a course toward and perpendicular to the horizon. Wondered if that might have been a piece of space junk entering on a different trajectory than the meteors.
It was active in my part of New England (30m west of Boston), at least around 11pm. I observed for about 10 minutes on my back deck and saw 5 streaks. It was quite cool and the humidity was low, and the MilkyWay was evident. Four streaks were from the NE to the SW, coming out of Persius, however, one long bright one was moving from the SE to NW.
I should have mentioned that in 1971, I was camping at 11k ft in the Rocky Mountains west of Denver at the foot of Mt Evans at the upper Chicago Lakes. I awoke at about 11pm to witness the Perseids exploding all over the sky. I watched mesmerized for about an hour, with bursts of sometimes 2 or 3 streaks in a second. A few were so bright, I lost my night vision for a minute or two. Although it was a 1/4moon that night, it was hidden by the cliffs to the east. I have never seen any such display since.
Congratulations on your performance on Stossel. You have a great media presence. You and Jo Nova should absolutely do more media work.
On a separate matter, I wonder if sometime you could do a brief article, no more than semi-technical, about how satellites measure temperature? And include an answer to “how does the temperature of the satellite impact the measurement?” I have axe to grind, no theory, no idea what the answer to my question might be, just curiosity. Others might be curious too.
Thanks for your post on the Perseids.
I read that they were not visible in the Southern hemisphere, and so didn’t look. Great to be shown.
Oops! That should have read “NO axe to grind”. Sorry.
Saw a couple of them around 10.30pm, BST, here in England. Only because I was out to see the ISS pass over.
It was pretty much a bust for me. Saw two on at 05:50 Tuesday morning while taking the dog out to do her business. One was a good one. I was called to drive late Wed. night and looked again at 23:00 when I took the pooch out before leaving. Nothing. Through the morning I was driving north on I-69 headed from Anderson, IN to Lansing, MI and didn’t see a single one through the windshield of my truck on the trip until I hit cloudy skies. As I approached Lansing there were thunderstorms putting on a pretty good light show.
Dr. Roy says:
“Expert opinion welcome.”
###
No problem. We have all kinds of opinion, even that kind.
About 65% of the way through http://aurigid.seti.org/ is a color photo of a spectrum of a Perseid. The closely spaced pair of magnesium lines at 516.7/517.3 nm, in the very slightly bluish green, shows strongly here. So does the orangish yellow pair of sodium lines at 589.0/ 589.6 nm.
The spectrum indicates perhaps a pyroxene mineral. There should have been iron, calcium, aluminum, silica,as well. Sodium and magnesium alone make no sense.
Some iron lines are mentioned. The orangish red one labeled O in the photo is a calcium line.
The second page (page 28) of http://adsabs.harvard.edu/full/1951PA…..59…28R has a table of lines in an observed Perseid spectrum. Iron and calcium figure highly, and there are a couple silicon lines.
Yep, somewhere in the literature the question has no doubt been addressed by a mineralogist who specializes in the mineralogy of meteorites. Pyroxenes are a class of silicate minerals with a variable composition. Meteorites tend to fall into categories based on mineralogy, the chemical signature of the pyroxene of the meteorite being a prime criteria.
Nice capture Dr. Spencer. Over four days in varying light conditions I saw 67 meteors, but only managed to capture a handful.
Roy
Please read this comment to Ball4.
And, Roy, you and your readers could learn so much from the planet Uranus, as discussed here.
This might be an unusual notion, that there is a huge debris field occupying a very elliptical orbit, perhaps all the way to the Oort cloud, consisting of cometary small particles that hold water. This huge area of small sized debris, billions of tons perhaps, is strung somewhat along the orbit path.
This might provide upper altitude water vapor and might explain temperature spikes of over one hundred thousand years. This debris would enter the earth’s atmosphere over possibly several years, creating elevated water vapor levels affecting radiation feedback. It would be little noticed, appearing to those lucky persons that see the meteors that they are normal meteors.
Most meteors come from comet fragmentation that is well cooked due to being near the sun many times, but not so these. To my knowledge water can be bound to rocky material, encased in it, and not be in a solid ice form. Any water would be cooked out of the comet matter first, and then air friction does the rest, vaporizing the stony material. At great altitudes, I suspect there is little solid science regarding how or if water can collect this way, but if it did there would be effects similar to what we see, IMO.