A Planetary Perspective

As I mentioned yesterday, we spent a few days in Mexico (Puerto Vallarta) recently. During that time, and considering my interest in things astronomical, I took a picture of a loose alignment of three planets, and the Moon, visible for a short period after sunset. The planets were Jupiter, Mercury, and Venus (in order of increasing distance from the horizon).

To see the details better, click on each picture.

Jupiter, the largest planet is closest to the horizon, actually seen through a light cloud. Mercury is slightly to the left of, and a little higher than Jupiter. The bright spot to the left of the Moon at the top of the picture, and somewhat lower, is Venus. The leftmost picture shows the actual scene; the right picture is the annotated version.

This is an interesting demonstration in planetary perspective. In this picture, Jupiter, the Solar System's largest planet (it has a mass equal to 318 times Earth's mass), is six times farther away from us than Mercury. Mercury is the planet closest to the Sun, Venus is next closest (our Earth is third) and Jupiter is the fifth of the major planets orbiting the Sun. Jupiter orbits five times farther out from the Sun than Earth. As shown in the picture, even that far away (we're talking about 900 Million km - 560 Million miles), Jupiter shows up brighter than Mercury. Mercury is around 160 Million km - 100 Million miles away. Venus (almost equal in size to Earth) is at this time about 110 Million km - 70 Million miles away. The closest is the Moon, "only" about 380 thousand km - 236 thousand miles away.


Quite apart from these scientific aspects, it was a pretty picture in its own right - certainly quite different from our wintery scene; the temperature at the time I took these pictures was about 22 degrees Celsius (72 F). On the left, you see a wider-angle view. Both Jupiter and Mercury are located to the left of the topmost dark cloud in the lower right (which seems to point straight to them).

We were staying with close friends, one block away from the beach, a couple of minutes' walk to this beautiful scene on Banderas Bay.

^

Away from the snow

I haven't posted anything since Christmas - we were away until yesterday, in Puerto Vallarta, Mexico. To our surprise, on our return, we still found nearly as much snow near our driveway as the day we left. Highly unusual for this city.

Derek had shovelled the snow out of our driveway, so it was easier to get back into the house. He said it was good exercise, and we certainly appreciated his efforts.

Derek had seen no reason for us not to go on this trip - he said that he felt well enough, and also took a little trip to Victoria while we were away. While he didn't enjoy the same kind of weather we had, it is nice to see that he can take some "time off", too.

Common sense?

I haven't written a "letter-to-the-editor" type of note to the media in a very long time, but today I wrote one to the "opinion page" of our local newspaper. It concerns the meteor seen in the sky over Alberta and Saskatchewan on November 20 of this year. Here's the gist of my (expanded for this blog) note:

On Tuesday, Dec.23, page B2 - "Metorite fall could yield scientific gold" - the article regarding the Nov. 20 meteor seen in Alberta/Saskatchewan (picture at left), I read with great interest, and a sense of sad dismay, that the more than 100 meteorites collected are all "...part of a 10-tonne, 10-kilometre-wide meteorite that broke up on impact with the atmosphere, spawning brilliant flashes of light that caught many eyes" (from the 9th paragraph in that article).

To begin with, a meteorite is defined as that part of a meteoroid which is found on the ground after travelling through the atmosphere. A meteoroid is the solid, original body before it encounters the atmosphere. The process by which this body disintegrates when it travels through atmosphere and which results in the 'brilliant flashes of light', and other associated phenomena (heat, ionization, occasionally sound) is called a meteor.

If the meteoroid (taken as a cube to make the basic calculations easy) had indeed been 10 km (about 6.2 miles) diagonally across, it would have had a mass of millions of tons (around 500 million - roughly equivalent to 1 trillion pounds); it would have struck the Earth almost totally intact, and caused a conflagration similar to what many scientists think happened on the Yucatan peninsula 64 million years ago, with the subsequent extinction of many species. If the 10-ton mass (about 20,000 pounds - i.e. about three GM Hummers) is taken as approximately correct, then the meteoroid that hit us, again taken as cube, would have been about 1.6 metres along each side. The meteorites shown in the newspaper's picture with Dr. Hildebrand appear to be of a "stony" nature - approximately 2.5 times the density of water. 10 tonnes of water is equal to 10 cubic metres of water, by definition - 1 cubic metre of water is equal to 1 ton. A 10-ton cube of water would measure about 2.15 metres along each edge. The "stony" equivalent cube of stone would therefore be 1/2.5th of 10 cubic metres, i.e. about 4 cubic metres. This would be a cube measuring about 1.6 metres on each side. How can one equate 500 million tons with 10 tons, or a cube of approximately 5.8 kilometers (5,800 meters) along one edge to 1.6 meters along the edge, or a trillion pounds to twenty thousand?

In reality, of course, the meteroid would not be a cube, but of some irregular shape. That makes calculations like these far more complex, but there is no getting away from the masses of material and the orders of magnitude involved.

What dismays me is the apparent incomprehension of and lack of innate feeling for the relationships between size, mass, weight and other physical characteristics and properties of the things that surround us, perhaps mixed in with lack of understanding regarding the metric system. It is as though common sense has left the authors and/or editors involved in the kind of published nonsense seen in the media far too often.

I gain little consolation from knowing that this kind of "innumeracy" is all too common. Not a month goes by in which I don't see such misrepresentation and misunderstanding in the newspapers or other media. Is this due to a lack of teaching in school?

This whole thing may be of no interest to anyone, but I had to vent my spleen here.

Merry Christmas

This year, we used only the top two/thirds of our artificial Christmas tree (Derek opted for a natural tree this year). We think it looks just as nice this year, and we did not need to move a lot of furniture to accommodate it. The heirloom decorations (many handmade) make it beautiful.

Merry Christmas, and a Happy and Healthy New Year to all of you!

The "full" Christmas tree

The tree this year



















A hand-made decoration. This one came from Erlyne's mother. Erlyne was a bridesmaid at our wedding, 44 years ago, and my wife and she are still in almost daily contact. She's family.

A quick year

It seems that each year goes by faster. It seems like last week that the previous winter was here. Right now, the snow is falling and I'll have to shovel some of it to clear the sidewalk. The grandchildren went off to school, taking along their snow slider board - they'll have a great time at school, where there is a small hill.

I have a theory why the years appear to go faster as you get older: each minute that goes by is a larger percentage of the rest of your life. So, enjoy what you can, you may not have the chance again.

the "meme"

Derek's post of yesterday asks to show a "meme", a picture on the 6th page of my flickr photostream, on this blog. Here is mine. I have no idea what the name means, or why it's called that. The closest word I can think of is the French word for "same" - même. So, perhaps it means something like "copied", but why the 6th picture on the 6th page?

This picture was taken during the "Symphonie of Fire" from the apartment balcony of our close, and longtime friend (she's part of the family) in West Vancouver, looking over English Bay, towards the False Creek area.

Winter again

At this time of year here, you take the nice days when you can get them. Today was such a day; my wife and I took the opportunity and went for a long walk (usually, we walk about half an hour per day, if weather permits). Our city has many nice parks, and there are a couple within reasonable walking distance. We chose Central Park (not the one of New York fame).

After we got home, the view out of our front window showed that our local mountains had been dusted with snow - the first signs of the coming winter. Time sure goes fast. You've seen similar pictures of the scenery on this blog before, but we never get tired of the view, even though we've lived in this house for 37 years. So, here is what attracted my attention today:


The pictures were taken through our front window with a Canon Rebel XT, set to an exposure time of 1/500th of a second, at ISO 800 "film" sensitivity, 75-300mm Canon zoom lens set to 255mm, at f 8.0 focal ratio. For those of you who want to know more about what these various settings represent, I recommend that you read Derek's ongoing dissertation about camera settings.