BILL BRYSON and SCIENCE

Bill Bryson is a good science writer.

Here are a few reasons: Dinosaurs, mining, Cholera

1.      It is general knowledge that the dinosaurs got wiped out by an asteroid.

Is it?
Since when?
The evidence?
Read "The Short History Of Nearly Everything".

I read this book before we “googled” to see if there was a story behind this “fact”

Bryson reports a geologist’s comment “I think we’ve found the crater”

This is the most obvious crater on the planet, so it was immediately the obvious suspect. Too bad that it was formed 65,000,000 years after the dinosaurs chilled out, give or take 55,000 years.

Bryson breezes through the story without being asked. The evidence points to Chicxulub ; for another good summary, try :  http://www.glencoe.com/sec/computered/col/chapter5/search_engines/yahoo/yahoo_6.html

2.      In “A Walk In The Woods” the coverage of the Centralia Coal mine fire made me check out how many mines are on fire, permanently. It does make coal mining appear to be as dangerous as gold or diamond, in spite of coal often being nearer the surface. Mining is high risk, everywhere.

3.      “At home”. John Snow was the hero in the struggle in against cholera. He came from the wrong side of the tracks, (this is a post on its own) but for 150 years he has been left off the honours board. Bryson simply restates the evidence – make up your own mind.   

Put your feet up !

THE HARDEST PLANET TO DISCOVER

THE HARDEST PLANET TO DISCOVER should be the one which shares the earth’s orbit, following Earth by exactly six months. Look for it with a telescope and, well, there would be the Sun in the way. So far we do not know if it is there.

BUT WE KNOW NOW THAT WE DO SHARE OUR ORBIT. We follow a lump of rock, just as Pacman pursues a pill or a pellet. The rock is 300m across, which makes it an asteroid; it would need to be under 50m to be a meteoroid. Its name is 2010 TK7

IT IS AT LAGRANGE POINT L4

Its orbit is very wobbly, because it is at lagrange point L4. But this makes it easier to find. Lagrange points are locations where the gravity from two neighbouring objects is equal, enabling objects to fall to them, or in and out of them for a wobble. Not only do asteroids fall into planets or moons, they fall into places such as L4.   

See http://en.wikipedia.org/wiki/List_of_objects_at_Lagrangian_points

This drawing shows the 5 lagrange points for
Sun (yellow) - Earth(blue)

THE QUESTION REMAINS

Is there anything PARKED AT L3 ? ? ?

New Moon and the Middle East; July to March

Last night I saw a thin banana moon; once again this waxing is underway.
What is there to look forward to this moonth?

The waxing is often a reminder that something anticipated is about to happen.

This month is survival. It is far too hot in Abu Dhabi to do much else?

The shadows from the lamps are exactly under the lamps. 

Abu Dhabi is on the Tropic of Cancer, the furthest from the equator where the midday sun passes exactly overhead.

The deck chairs are empty - Noel Coward would say there can't be any mad dogs or englishmen here

Yet there is a couple of people on the tennis court. Getting some stamina training for Wimbledon maybe (photo was taken 21st of last moonth)

Next new moon is the start of Ramadan. Happily we are allowed to slow down under the August sun this year.

In December the new moon will remind us that there is a Lunar Eclipse; from November to April we will start watching again at each New Moon to see the fastest thing in the sky rush up from the West past Venus and then on past Jupiter. Each month the gap between Venus and Jupiter will shrink, till there is a Conjunction in March. 

How would you know which of all those dots is Venus?

The brightest night sky objects are

1 the moon

2 Venus

3 Jupiter; 

Note that Venus and Jupiter are brighter than any star; that they are on the line taken by the moon makes them very easy to find.

In Abu Dhabi, the sky is hazy enough that these three are often the only objects that can be seen.

A MIDNIGHT SUN? Not where I live

I was working with some 6th Graders. Some have impressive general knowledge, but it turned out that there was little awareness that there are places on Earth where the sun shines 24 hours a day. Their home is just off the Tropic of Cancer, so to get an idea of how much variation of sunshine time there can be as one moves away from the equator, we chose some data from http://www.timeanddate.com/  (see below)

AT THE EQUATOR the daylength differs from one solstice to the other by only two minutes. Year round, the day is 12 hours and 7 minutes long, within a minute.

AT THE TROPIC of CANCER the June sun is up for 20 minutes short of 14 hours. Add the fact that sun passes overhead and the days are very hot, and the nights are not long enough to allow much cooling. The December sun is up for three hours less and does not even reach an altitude of 45° Evenings can be romantic; they are often cool and calm

INSIDE THE ARCTIC CIRCLE at Tromsǿ, the summer Solstice sun has not set for five weeks and will not for a further five. Ten weeks of Midnight Sun and only 2° inside the Arctic Circle.

The December solstice is in the middle of a 7 week period wherein the sun will not be seen

So for any given date, how long is a day on this planet? It depends on the season and the latitude.

Location	Latitude	Date	Day length	Time Solar Noon	Altitude Solar Noon
Quito	0°15S (equator)	21 Jun	12h 06m 32s	12:16	66.3°
Quito	0°15S	21 Dec	12h 08m 18s	12:12	66.8°
Abu Dhabi	24.8°	21 Jun	13h 39m 11s	12:24	89.0°
Abu Dhabi	24.8°	22 Dec	10h 37m 23s	12:21	42.1°
Tromsǿ (Norway)	69.7° N	21 Jun	24 hours	12:46	43.8°
Tromsǿ	69.7° N	22 Dec	Zero hours	11:42	1.9° below

Say IF . . . THEN . . . and you are talking Science, even if you are 10 yrs old and saying the earth is round

Over a few years, our family had several weeks of holidays in a "house" 50 metres from a rocky shore. I was about 10. No electricity.

A luxury was water that ran from a tap.  Sometimes we had to clear a blockage at the intake pipe, about 30 metres up a steep stream behind the house. After sorting this one morning, I sat down and looked out to sea. Surprise! From a few metres up a hill, the horizon was above a particular rock, yet from the water’s edge, the top of that rock was above the horizon. 

Another time, at the water's edge there was a ship at the horizon with a blue hull. Yet climb just a couple of metres and the ship had a red stripe along the water line.

Meaning?

IF THE HORIZON shifts away from you when you climb even a couple of metres, THEN THE SURFACE of the water between you and the horizon is curved. THE EARTH is ROUND!