Astronomy

[YesNo]

I watched the video in the first link. I liked the phrase "universe's first light" used there. I was not able to access the second link.

[Dreamwoven]

The second link is not accessible for me either.

[Dreamwoven]

EarthSky is about how the Oort Cloud got its name: a Dutch astronomer in 1950: http://earthsky.org/space/jan-oort-b...ons-oort-cloud.

[YesNo]

It is interesting that the existence of the Oort cloud is still considered a theory, but those comets have to come from somewhere.

[Dreamwoven]

The problem is that the Oort Cloud is itself a concept rather than proven fact. It covers a huge area of space, See https://en.wikipedia.org/wiki/Oort_cloud

[Dreamwoven]

Extract from Society for Popular Astronomy:

Oddly enough Gaia is not described in Wikipedia. Definitely a miss as Gaia was launched in 2013:

Saturday’s London meeting: Gaia – the Milky Way and Beyond
It sounds like something from Star Trek: ‘Its five-year mission – to seek out new worlds, to reveal cataclysms deep in the Universe, and to discover strange objects that as yet we can’t even understand.’ But this is not the Starship Enterprise, it is the European Space Agency's flagship Gaia mission, launched in 2013. It will produce the most accurate three-dimensional map of our own galaxy, the Milky Way. As well as surveying millions of stars throughout the Galaxy, Gaia will reveal transient events taking place far out in the rest of the Universe, including stars exploding as supernovae and being swallowed by black holes.
Our main speaker, Dr Morgan Fraser of Cambridge University, will explain how Gaia will achieve its amazing precision measurements, and give us a taste of some of the science highlights so far.
Following the break, Robin Scagell will look at some of the highlights in the sky for the next three months, including the Transit of Mercury. Comet Section Director Stuart Atkinson will speak about Comets: Fear, Fact and Fiction and discuss why comets have been blamed for so many disasters in history, plus taking a look at the Rosetta mission.
The meeting is open to all SPA members and friends, and begins at 2 pm this coming Saturday, 30 April. The venue is the Khalili Lecture Theatre of the School of Oriental and African Studies, near Russell Square, London WC1H 0XG. The nearest tube station is Russell Square. For a map of the location and more details, go to the SPA website.

[YesNo]

Our main speaker, Dr Morgan Fraser of Cambridge University, will explain how Gaia will achieve its amazing precision measurements, and give us a taste of some of the science highlights so far.

In all of these studies I wonder what the precision is of the measurements including a measure of the margin of error. On top of that is how those results are obtained.

[Dreamwoven]

I think this has to be two questions that should hopefully be answered at the session. Information on Gaia seems to be very sparse.

[Dreamwoven]

Repeating bursts of radio waves from mysterious object (from an article in Popular Astronomy): "Fast Radio Bursts" (FRB) from outside the Milky Way have been noted since they were first discovered in 2001. See https://en.wikipedia.org/wiki/Fast_radio_burst. They remain an unexplained mystery.

[YesNo]

That was the first I heard of fast ratio bursts. But there is a lot I haven't heard of. It appears they are still rare. It looks like they come in a repetitive fashion which is probably what makes them stand out.

[Dreamwoven]

The good news is that measures are being taken to sharpen their observation tools to enable finer pinpointing of the source of FRBs. "The event must be extremely energetic to be detectable from earth" (p.6).

[Dreamwoven]

In the same issue there is an article on ice giants (Neptune and Uranus). We know very little about them, all from Voyager 2 over 30 years ago. They are definitely different from Jupiter and Saturn which are not ice giants but which have gaseous envelopes. So many questions need to be addressed.

[YesNo]

It is interesting that Neptune and Uranus are ice giants and unlike Jupiter and Saturn. I previously assumed those four planets were similar being so large.

I remember looking at Mars and Saturn in the early morning last week as the Moon passed above them.

[Dreamwoven]

I also assumed the four giant planets were similar, but they are not. The further out ice giants are also different from each other, as well as from the two gaseous giants, Jupiter and Saturn. Neptune's surface is tossed by violent tornados and supersonic winds and has an earth-sized "Great Dark Spot". Uranus is deep-frozen.

There is a lot more about the ice giants, especially their many moons. Neptune has 14 moons, one, Triton, being bigger than Pluto and accounting for 99 percent of the mass of matter encircling Neptune. It orbits Neptune in the opposite direction to the planet's rotation, suggesting it was captured by Neptune, so is probably a dwarf planet from the Kuiper Belt.

There is a lot more about the moons of the ice giants, planets which, until the 1980s were just specks in space. They need re-visiting to understand them better.

Uranus has 27 moons (!), two of which Cordelia and Ophelia are described as shepherd moons for the epsilon ring around Uranus.

Source: Popular Astronomy May/June 2016 "Return to the Ice Giants" by Joseph Scaife (pp. 15-17).

[YesNo]

That Triton might have been captured by Neptune is a nice way to think about it. I didn't know it had an orbit opposite to the planet's rotation. If Neptune has tornadoes it must have an atmosphere.