Astronomy

It is too cloudy to see much tonight, but I find Gemini near Taurus and Orion on an atlas so I should be able to pick out the constellation later. The photos were nice in the link.

New Horizons has been woken out of hibernation and working again, ready to pass Pluto. It can be tracked here: http://pluto.jhuapl.edu/mission/whereis_nh.php, scroll down for the two perspectives on this coming flyby. Full Trajectory Overhead and Full Trajectory (Side view).

It looks like Pluto is the last planet to be explored and I didn't realize it was a double planet. It will be interesting to see the pictures that come back from New Horizons.

Yes, as far as we know it is the last and also the least explored. In 2006 it was re-classified as a Dwarf Planet, a denizen of the distant Kuiper Belt.

There is still controversy over Pluto's status and presumably also of Charon, almost as big as Pluto,yet also its moon. If a dwarf planet can have another dwarf planet of similar size as a moon circling around it.

At this distance from the sun it doesn't take a large mass in the Kuiper Belt to be held in orbit round the sun and also as a "moon" of another small planet/dwarf planet, together as a double (dwarf?) planet.

The last planet to be explored makes Far Horizons especially interesting.

I've used NASA's website on Solar System Exploration for much of what I have learned of Pluto and the other dwarf planets.

What do you make of all this?

I found the idea of "tidal locking" interesting. Pluto and Charon face each other with Charon's orbit taking the same time as Pluto's rotation.

I thought those scientists agreed to call it something other than a planet. I understand from the link that Pluto is a dwarf planet because it has not "cleared the neighborhood" in its orbit of other objects such as those in the Kuiper belt. However, since Pluto crosses Neptune's orbit does that mean Neptune has not cleared the objects in its neighborhood?

So far away from the sun, on the edge of the Kuiper belt, the gravity of the sun is much weaker while the gravity of planets, dwarf planets, comets and asteroids are commensurately enhanced. What you write about the orbit of Pluto crossing the orbit of Neptune, I guess in longer time spans it is possible that the two bodies might be at risk of collision, though this is not, I understand, likely for many centuries.

The orbit of Pluto is angled differently from the other planets, so it crossed the track of all the planets as a result. Uranus is also a possible collision course, though again not for a very long time. The second of the two perspective diagrams of New horizons route makes this clear.

The Winter Solstice is the time to watch the Ursid Meteors, as EarthSky have explained. Meteors display at radiant points. There is a full catalogue of meteor showers at http://earthsky.org/astronomy-essent...r-shower-guide.

I have to confess I have never seen a meteor shower, you may need to camp out in the night under the starts in a sleeping bag to keep warm. Can't do it in midwinter, not here in Northern Sweden. Much the same goes for comets, though being larger and more visible can be a more visually dramatic experience. See http://www.popastro.com/comet/findercharts/index.php

I have seen a few scattered meteors but never a shower of them. Comets are at least more permanent. I have seen a handful of those. There was one more than 15 years ago that was very visible. I remember carrying my daughter out onto the patio and showing it to her. I pointed to it, but I wonder if she realized what I was pointing to.

The one you saw in the mid-1980s was probably Halley. I saw that too, during a stay at the Bålsta Anthroposophy Village in Sweden. It was the most striking comet I have ever seen (though that's not saying much) Cometography.com Cometography is run and maintained by Gary W. Cronk and is remarkably comprehensive. I may make comets one of my special interests.

That was a very detailed comet cite. I will try to see C/2014 Q2 (Lovejoy) which binoculars should make available if the sky is dark enough. I haven't had many evenings when stars were visible.

I think the comet I saw was Hale-Bopp: http://en.wikipedia.org/wiki/Comet_Hale%E2%80%93Bopp. In 1995 my daughter would have been about the right size to carry her onto the deck.

You are almost certainly right. Hale-Bopp it was, not Halleys: http://en.wikipedia.org/wiki/Comet_Hale–Bopp

Space.com has written about NASA's attempt to capture an asteroid and put it in orbit around the Moon. The idea being to study it. Won't be for a few years but should be interesting.

After all the talk of asteroids coming near enough to crash into Earth, I am surprised they would want to do something like that. But if they can move an asteroid toward the moon, they should be able to deflect one that strays our way.

I think that is partly behind the idea, but I also thought it was a bit high-handed. I doubt it is big enough to be a problem if it should crash to earth, but some of these space activities probably have a degree of showmanship about them.

I have just joined Popular Astronomy, which is about my level of astronomy knowledge. It has a forum for a variety of debates. This is one of the shorter items in the electronic news bulletins put up there. Others or extracts from longer ones may follow.

The SOCIETY for POPULAR ASTRONOMY

Electronic News Bulletin No. 386 2014 November 02
by Robin Scagell

SMELLY COMET!
University of Bern

How does a comet smell? Since early August the Rosetta Orbiter Sensor
for Ion and Neutral Analysis (ROSINA) is analyzing the gases of the
comet Churyumov-Gerasimenko with its two mass spectrometers. The
chemistry of the coma of the comet is surprisingly rich already at
more than 400 million kilometres from the Sun. The gases detected
include hydrogen sulphide, ammonia, formaldehyde, hydrogen cyanide,
methyl alcohol, sulphur dioxide and carbon disulphide. Such a mixture
would make a most unattractive (not to say lethal) smell on Earth, but
the density of those molecules in the cometary coma is still very low,
and the main constituents of the coma are water and carbon dioxide
molecules mixed with carbon monoxide. That all makes a scientifically
interesting mixture that may be relevant to studies the origin of the
Solar System, the formation of the Earth and the origin of life. The
idea was that at distances beyond 3 astronomical units the comet would
mostly sublimate the very volatile molecules carbon dioxide and carbon
monoxide, so the fact that ROSINA is already detecting so many more
molecules at large distances from the Sun comes as quite a surprise.
A quantitative analysis will show how the comet compares with other
comets for which data are available (mostly from remote sensing). The
comparison will reveal whether Churyumov-Gerasimenko, being a Kuiper-
Belt comet, differs from the better-known Oort-Cloud comets, and that
may then shed light on some characters of the cloud from which the
Solar System emerged.