The Perseids

Yesterday, I looked for the "falling stars" I talked about in the previous post. I saw a couple of bright ones around 10:30pm, one of them through binoculars. That one did not seem to be part of the Perseids; it came from a different direction. However, it was quite bright, and I could see it break up into several smaller pieces just as it finished. That happens when the heat buildup inside gets high enough to explode the original meteor.

Unfortunately, a broken cloud cover drifted in around 10:45pm, so I probably missed more of the Perseids. I went into the house at that time. Though I woke up a couple of times during the night and the sky had cleared again, I didn't see any more Perseids during the few minutes I looked out the Window at those times.

Perhaps other people had more luck. According to predictions, there should have been a fair number visible this year.

Falling stars

For those of you interested in seeing a phenomenon in the sky without the need for a telescope or binoculars:

This weekend we have the annual re-appearance of the Perseid Meteor Shower. What we should see (barring cloudy skies and too much light pollution from surrounding lights) is the "burning up" in the Earth's atmosphere of tiny particles which Earth encounters every year in its orbit around the Sun. The "debris" which the Earth encounters at this time each year is shed by a comet which also orbits the Sun, named Swift-Tuttle (the discoverers). If you are located away from the big cities, and have a clear sky, you might see a "falling star" once a minute, or so. In the cities, you'll only see the brighter ones, but there is always a possibility of a really bright "fireball". The maximum "rate" is expected on Sunday night, into Monday morning.

Look towards the north-east when the sky gets dark. Here are two images of the same area generated by the "Starry Night" computer program simulating the view at about 11:15pm. The Perseus constellation is pictured just below centre in each image. The lines connecting the stars are imaginary, they don't exist in reality. Click on the pictures for a larger view:









As you would see the sky away from the city.









Shown with annotation.




The frequency of falling stars will increase after midnight, when the Earth's rotation carries you you around to a more "head-on" direction. This is the direction into which the Earth is heading on its way around the Sun.

The Perseids get their name from the constellation from which they appear to come, called the "radiant". This purely a perspective effect; the stars which comprise this constellation are infinitely farther away than this comet-debris, which originates in the solar system. As the night progresses, this radiant moves higher and higher into the sky, due to the Earth's rotation.

Good luck, and clear skies!

Out of this world

Last night, Hilkka and I attended a presentation by the Royal Astronomical Society of Canada Vancouver Centre . Eric Dunn, a well-known popularizer of Astronomy and long-time member, gave us a talk about the latest developments in Solar System exploration. Much of our present knowledge comes from the technical marvels called "orbiters" - vehicles sent from Earth to "circle" or pass by other planets, their "moons", or to probe comets, asteroids, etc., all part of our solar system.

Because the difficulty of reaching some of the planets, we have varying amounts of knowledge about them. Also, several of them (i.e. the "gas giants" Jupiter, Saturn, Uranus, Neptune) have no solid surfaces that we know of, or are too inhospitable likely ever to support a human presence (Venus, or Jupiter's moon Io, for example). Therefore, more detailed exploration efforts are currently directed to those places where human beings could survive. The most likely of these is the planet Mars.

Now, getting there is not accomplished without some better technology than is currently available. As a first step, plans are being made to land people on our Moon again. From 1969 to 1972 the USA landed people on the Moon and returned them to Earth, but, incredibly, there is no "hardware" on hand right now to do this again - for instance, no spaceworthy "Saturn" rockets (the biggest rockets ever built) exist. There are a lot of extras that need to go along, most importantly a "return vehicle". All these require prodigious amounts of energy (fuel, meaning really big rockets) to lift out of Earth's "gravity well". At the moment, this kind of spacecraft is not available.

This means, of course, that we also cannot get to, and return from Mars right now. None-the-less, to land people on Mars, you need to know as much as possible about it beforehand. To this end, there have been many "robot" explorers sent there. Some of these orbit Mars, probing it with a variety of cameras and sensors; a couple are actually on Mars' surface - the spectacularly successful "rovers", Spirit and Opportunity. You can see pictures and related information here: http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20070503a.html

The talk by Eric mentioned other worlds as well. Perhaps the most successful planetary explorer ever is the Cassini orbiter which has taken a multitude of pictures and transmitted to Earth a huge amount of information about Saturn, many of its moons (we know of about 60 at last count) and the environment out there. For instance, I showed a picture of a "backlit" Saturn on an earlier post, which Cassini sent.

There are many other images at: http://www.nasa.gov/mission_pages/cassini/multimedia/index.html

Every now and then, one needs to get away from one's problems and concerns. I find my "getaway" in the fields of Astronomy and space exploration. If you're interested in some of this, link to http://www.nasa.gov/, or http://www.jpl.nasa.gov/, and do some "link-hopping".

Little things mean a lot

As you've probably read on Derek's blog, things are progressing slowly, but steadily. We're pleased that he's gained some weight - it'll help with his continuing fight against his cancer.

We live next to each other in a duplex, with connecting balconies. This arrangement makes it possible visit on short notice, and with no effort. So, it is easy for Derek and/or his family to come over. Last night Derek came to visit us, to our great pleasure. Also, Marina, Dereks' older daughter, likes to come over in the evening for some "quiet time", as she calls it, and, as grandparents, we consider this to be a real compliment from her. Many times both Marina and Lauren, Dereks' younger daughter, are here for a visit, and we can take them at any time Derek or Airdrie (or both) need some time for themselves or when they need to do other things. Sometimes Marina and Lauren sleep over; it's a wonderful thing that we have Dereks' "clan" so close. This kind of thing (all the family under one roof) used to be normal; nowadays families are often spread all over the globe, and I think something goes missing when that happens. In any case, our situation is certainly of help to Derek in his current bout with his illness.

"Little" things indeed.

Out some more

Late in the afternoon yesterday Derek phoned us from our neighbourhood mall. He had had a meal by that time and he and family had spent a couple of hours there. The wheelchair came in handy, apparently.

It's good to know that he's able to get away from the house for more than a few minutes.

Get away

Don't fly me to the Moon - fly on Mars instead:
http://mars.jpl.nasa.gov/odyssey/gallery/video/movies/ThemisFlybyMusic.mpg

This is a movie of a simulated flight over Mariner Valley on Mars, based on data collected by Mars orbiter instrumentation. Download time is over a minute for a hi-speed connection.

Not much to report

We haven't talked to Derek in a couple of days, but he's taking it easy, from what Airdrie and our granddaughters tell us. As mentioned before, it's a slow and gradual recovery for Derek.

We have guests from Europe ourselves for a couple of days, so we're showing them the Vancouver sites - the weather is beautiful.