Something for the Weekend

First things first, Earth. NASA has just released the most detailed whole planet pictures to date showing our small, mostly blue, ball in stunning detail. Can you pick out your location?

http://gizmodo.com/5478787/the
-most-accurate-highest-resolut
ion-earth-view-to-date?utm_sou
rce=feedburner&utm_medium=
feed&utm_campaign=Feed:+gi
zmodo/full+(Gizmodo)

(Just click to enlarge)

To go hand in hand with the new pictures is this animation showing plate tectonics and how our planet has evolved over the last 600 million years and our predicted future (this is from the Northern University of Arizona’s Geology dept)

http://www.youtube.com/watch?v
=uGcDed4xVD4

Finally as a follow up to two weeks ago’s focus on STS130 here is a nice photographic record of the mission from the guys themselves.

http://www.sacbee.com/static/w
eblogs/photos/2010/02/space-sh
uttle-endeavours-missi.html

Internet security and Prime numbers

Ever wonder how websites like Amazon.com keep your personal information, like credit card or check numbers, safe from the internet bad guys? Well, here’s the how.

At the Amazon website you enter in your private info, press “send”, and your internet browser quickly encodes your data and sends it off to Amazon. To make sure no one but Amazon can view your info, each code has a lock that can only be opened with the correct key, which Amazon has.

This is where prime numbers come into play. Prime numbers are those divisible only by themselves and 1, like the numbers two, three, five, seven, eleven etc. Of course these are very small prime numbers, but there are infinitely many of them and they can get big; the biggest found so far is thirteen million digits long!

The lock on the code protecting your private info is a very big number which is the unique product of two prime numbers, and the key to this lock are exactly these two primes. As a small example, take the number fifteen.

If this were our “lock” number, then the two primes three and five would be our “key”; since both are prime and three times five is fifteen. Unlike the small example however for a larger “lock” number it is nearly impossible to find the two “key” primes if you don’t already know them.

The best computers in the world might take years to find the “key” primes of a “lock” number only three-hundred digits long. Thankfully websites like Amazon typically use “lock” numbers at least this big, thus making it nearly impossible for a bad guy to sneak a peak at your private info online.

All points north

Antarctica is 98 percent ice and 2 percent barren rock. The average thickness of the ice sheet is 7,200 feet. This amounts to 90 percent of all the ice and 70 percent of all the fresh water in the world. If the ice cap were to melt, the sea level would rise by an average of 230 feet.

The bed of nails and how to do it the scientific way

Quite rightly the prospect of lying down on a bed of sharp pointy metal things isn’t something to be done lightly, because, lets face it, its going to hurt.

Or will it?

The bed of nails trick is, when taken apart by science, not as painful as you might first imagine.

Think of it this way. You can press your fingertip lightly on a nail without it hurting. If you put the other end of the nail on a scale and then press, you can see how many pounds of pressure you can put on one nail without it hurting you. Don’t press too hard!

Suppose the answer is one pound. You can press down on a nail until the scale reads one pound, and beyond that you don’t want to press any harder. Okay, one pound of pressure per nail is safe for you. So, if you weigh 200 pounds, you can lie on a bed with at least 200 nails on it and not be hurt. That’s because each nail is supporting only one pound and your weight is evenly distributed.

And there you go, how to lay on a bed of sharp objects without the need for any guru’s, incantations or other mumbo jumbo.

Lay carefully and evenly though if you don’t want to become a human pin cushion.

A spoonful of honey

It takes twelve bees a lifetime to make one teaspoon of honey.

Meteorological Mythology

Which area of science would you expect to find elves and sprites ?

Answer Meteorology - Sprites are large-scale electrical discharges high above a thunderstorm cloud. Elves, or ‘Emissions of Light and Very low frequency perturbations from Electromagnetic pulse Sources, are a glow caused by colliding electrons.

Recognizing Rhesus

Recent tests have shown that at six months a human baby can tell the difference between two Rhesus monkey faces just as well as two human ones. By twelve months this ability is gone, the baby can recognize the difference between the human ones, but the monkey faces all look the same. This is giving scientists an insight into how our brains are wired at birth with innate abilities, but our brain changes over time using a "use it or loose it" philosophy.

Measuring the Moon

The Moon is 27% the size of the Earth.

Radius of Moon = 1738 km

Radius of Earth = 6378 km

Comtemplating Casimir

Today's Factoid isn't so much a fact as an explanation.

The Casimir effect is a small attractive force that acts between two close parallel unchargedconducting plates. It is due to quantum vacuum fluctuations of the electromagnetic field.

The effect was predicted by the Dutch physicist Hendrick Casimir in 1948. According to the quantum theory, the vacuum contains virtual particles which are in a continuous state of fluctuation. Casimir realised that between two plates, only those virtual photons whose wavelengths fit a whole number of times into the gap should be counted when calculating the vacuum energy. The energy density decreases as the plates are moved closer, which implies that there is a small force drawing them together.

The attractive Casimir force between two plates of area A separated by a distance L can be calculated to be,

π h c

F = ------- A

480 L ⁴

where h is Planck's constant and c is the speed of light.

The tiny force was measured in 1996 by Steven Lamoreaux. His results were in agreement with the theory to within the experimental uncertainty of 5%.

Particles other than the photon also contribute a small effect but only the photon force is measurable. All bosons such as photons produce an attractive Casimir force while fermions make a repulsive contribution. If electromagnetism was supersymmetric there would be fermionic photinos whose contribution would exactly cancel that of the photons and there would be no Casimir effect. The fact that the Casimir effect exists shows that if supersymmetry exists in nature it must be a broken symmetry

According to the theory the total zero point energy in the vacuum is infinite when summed over all the possible photon modes. The Casimir effect comes from a difference of energies in which the infinities cancel. The energy of the vacuum is a puzzle in theories of quantum gravity since it should act gravitationally and produce a large cosmological constant which would cause spacetime to curl up. The solution to the inconsistency is expected to be found in a theory of quantum gravity.

Some examples in practice

Since L is in the denominator, the bigger L gets, the smaller the force will be; and because the force goes as the fourth power of L , the drop-off with increasing distance will be really huge. So let's make L small--say, one micron--together with big one-square-metre plates:

π × 6.6 × 10 ^-34 × 3 × 10 ⁸ × 1

F = ------------------------------ newtons

480 × 10 ^-24

or 1.3 mN. Now, since the weight of 1 kg is about 10 N, then 1.3 mN is the weight of 0.13 grammes. Which is pretty small, but measurable, except that putting two 1 square metre plates a micron apart would be difficult in practice. But using smaller plates leads to smaller forces. For instance plates with area 1 square centimetre placed 1 millimetre apart would feel a force equivalent to the weight of 10 ^-17 grammes, which is vastly smaller!

Missiles in the Marshall's

The largest coral atoll in the world is Kwajalein Atoll in the Marshall Islands. Although like some if its neighbours this atoll hasn't been used for nuclear testing It is used by the US as a missile-testing facility with two airbases currently in operation on the windswept island.

http://virtualglobetrotting.co
m/map/kwajalein-atoll/view/?se
rvice=0

The twilight of a great Endeavour

As an addition to the below STS-130 Endeavour stuff, my favorite astronomer Phil Plait aka BadAstronomer has just posted this blog post which has a stunning movie and photo of Endeavour in twilight, probably for the last time,beautiful but kind of sad really.

http://blogs.discovermagazine.
com/badastronomy/2010/02/13/t w ilight-of-the-shuttle/

Something for Valentines weekend and space lovers

Want to impress the Geek in your life?

Here are the instructions for a mathematical multi dimensional Valentine card.

http://timesonline.typepad.com/science/2010/02/make-a-mathematical-valentines-card.html

Now for some International Space Station news.

The last big piece of construction is going on up there at the moment as a bay window and extra crew space is being installed by the STS-130 crew.

Here are links to the STS-130 launch (the last night launch planned for the program)

http://www.youtube.com/watch?v=hsx0NsPlZ_M

and a story about the window and the room called “tranquillity”.

http://nwitimes.com/news/national/article_155273d2-685c-5b50-a5c3-08434418a3dc.html

Finally here is another video showing a recent tour of the ISS from end to end.

http://www.youtube.com/watch?v=H8rHarp1GEE

Look out for the Loo, the speed limit sign and just how cramped it is up there! (Whistlers and claustrophobe’s need not apply)

Let me know you love me

The pupil of the eye expands as much as 45 percent when a person looks at something pleasing.

Understanding if something is endothermic or exothermic

To illustrate these two opposites in terms of thermodynamics (and a bit about Boyles law) I thought I’d share a classic exam answer from 1997.

Dr. Schambaugh, of the University of Oklahoma School of Chemical Engineering, was known for asking questions such as, "why do airplanes fly?" on his final exams. His one and only final exam question in May 1997 for his Momentum, Heat and Mass Transfer II class was thus: "Is hell exothermic or endothermic? Support your answer with proof."

Most of the students wrote proofs of their beliefs using Boyle's Law or some variant. One student, however, wrote the following:

"First, we postulate that if souls exist, then they must have some mass. If they do, then a mole of souls can also have a mass. So, at what rate are souls moving into hell and at what rate are souls leaving? I think we can safely assume that once a soul gets to hell, it will not leave.

Therefore, no souls are leaving. As for souls entering hell, let's look at the different religions that exist in the world today. Some of these religions state that if you are not a member of their religion, then you will go to hell. Since there are more than one of these religions and people do not belong to more than one religion, we can project that all people and souls go to hell. With birth and death rates as they are, we can expect the number of souls in hell to increase exponentially.

Now, we look at the rate of change in volume in hell. Boyle's Law states that in order for the temperature and pressure in hell to stay the same, the ratio of the mass of souls and volume needs to stay constant. Two options exist:

1. If hell is expanding at a slower rate than the rate at which souls enter hell, then the temperature and pressure in hell will increase until all hell breaks loose.

2. If hell is expanding at a rate faster than the increase of souls in hell, then the temperature and pressure will drop until hell freezes over.

So which is it? If we accept the quote given to me by Theresa Manyan during Freshman year, "that it will be a cold night in hell before I sleep with you" and take into account the fact that I still have NOT succeeded in having sexual relations with her, then Option 2 cannot be true...Thus, hell is exothermic."

The student, Tim Graham, got the only A.

Go West

Hawaii is moving toward Japan at a rate of 4 inches every year.

Cold Calm

The calmest place on Earth is on top of an icy plateau in Antarctica known as Ridge A, several hundred miles from the South Pole. It is so still that stars do not twinkle in the sky because there is no turbulence in the atmosphere to distort the light.

The fastest manned vehicle/So near and yet so far

The fastest manned vehicle record has been standing for quite some time as it's held by APOLLO 10 which was crewed by Thomas Stafford, John Young and Eugene Cernan. On their return journey from the moon they clocked an impressive 39,897km/hr (11.08km/s or 24,791mph) on the 26th May 1969.

Apollo 10 was a dry run for the eventual first landing of APOLLO 11 and Young and Cernan in the lunar module "Snoopy" came within 15.6km of the Sea of Tranquility (the module was deliberately not set up to land so that the crew, however tempted, wouldn't attempt an unauthorized landing).

PS.Young and Cernan would join the elite 12 on later Apollo missions though, so they did eventually set foot on Luna.

Why do Bats hang upside down?

Bats leg arrangements are not the same as birds. The thin membrane of a bats wing stretches from its elongated fingers to its legs, and is then attached to the sides of its body. Most bats also have a large membrane connecting both legs, which acts like a pouch and is used to capture insects. This means the legs of a bat are not free to do their own thing, but are tangled in wing and tail membrane.

This has meant that bats have not been able to develop the many different types of legs we see in birds – long legs, short legs etc. Anyhow the evolutionary upshot of all this is that for bats it appears the easiest way for them to stow away the membrane is to hang upside down.

A different way of seeing things

Animals do not necessarily see things the same way that you do. While we have three cone cells which allow us to see colour, some birds and fish have four types of cone cells, so their colour vision could be described as more precise than ours. Owls, however, like many other nocturnal animals, have no cone cells. While they have excellent vision, they perceive the world in black and white. Bug zappers use ultraviolet lights to attract mosquitoes because they see the short-wavelength violet and ultraviolet light, but not yellow or orange. And you know how a matador uses a red cape to entice a bull to charge? Well, the colour is for the spectators. Bulls have only two kinds of cone cells and they do not perceive red as a colour at all.

Can-do Carbon

Graphene, a one atom thick planar sheet of carbon atoms bonded in a honeycomb crystal lattice, featured in the latest episode of the CBS comedy The Big Bang Theory. Here are a few facts about that most abundant and flexible of elements, carbon.

Carbon is the basis of organic chemistry, as it occurs in all living organisms.

Carbon is a non-metal that can bond with itself and many other chemical elements, forming nearly ten million compounds.

Elemental Carbon is made in the interiors of dying stars.

Carbon compounds have limitless uses. In its elemental form Diamond is a gemstone and used for drilling/cutting. graphite is used in pencils, as a lubricant and to protect against rust. The isotope carbon-14 is used in radiocarbon dating.

Carbon has the highest melting/sublimation point of the elements. The melting point of diamond is 3500 degrees C with the sublimation point of carbon around 3800 degrees C.

Pure carbon exists free in nature .and has been known since prehistoric times.

The origin of the name "carbon" comes from the Latin word Carbo for charcoal. ~The German and French words for charcoal are similar.

Pure Carbon is non toxic, although inhalation of small particles such as soot can cause damage to lung tissue.

Carbon is the fourth most abundant element in the universe (hydrogen, helium and oxygen are found in higher amounts by mass).

Ample aorta

Blue whales have large enough aortas (the main blood vessel) for a human to crawl through. (this factoid comes courtesy of OMG facts)

Stone skimming scientifically

In order to skim a stone it must be spinning and tilted slightly so that its leading edge is a bit higher than its trailing edge, in order that the trailing edge will hit the water first. But even though it has hit the water, the stone wants to keep spinning along the same axis, like a gyroscope. So the whole stone skips up from the surface of the water, flies a little distance, and then repeats the process. It will keep jumping as long as the stone is spinning. Gyroscopes always try to keep spinning in the same direction, so rather than flipping over when the stone hits the water, it jumps in order to keep its axis pointing in the same direction.

You can’t skim a spherical stone because there is no trailing edge to hit the water; and you can’t skim a stone that isn’t spinning because it would simply sink.