Polar Ice Page Update

So I updated the polar sea ice page once again. Note the ever growing area of sea ice on the Southern hemisphere.

Polar Sea Ice Page Updated

I had to update the Polar Sea Ice page because it referred to the record ice extent as data of 2007 while in reality the record extents (minimum in the Arctic, maximum in the Antarctic) are currently being updated every day (as of writing this on 2012-09-02).

I originally did not expect this to become necessary so soon. The reason for this misjudgement of mine is the Atlantic Multi-decadal Oscillation. Back in 2008 I learned that it should currently be counteracting the effect of global warming on the Arctic region.

A BBC article of 2008-05-01 puts it like that:

The Earth's temperature may stay roughly the same for a decade, as natural climate cycles enter a cooling phase … A new computer model … suggests the cooling will counter greenhouse warming. However, temperatures will again be rising quickly by about 2020 …

In contrast, a recent BBC article (2012-08-27) has this to say:

A recent paper from Reading University … [estimated] that between 5-30% of the recent ice loss was due to Atlantic Multi-decadal Oscillation - a natural climate cycle repeating every 65-80 years. It's been in warm phase since the mid 1970s.

Allow me to call this difference in description a little strange.

NASA: Arctic sea ice reaches record low

Asteroids Missing Earth: What Means “Close Call”?

Every now and then you read about asteroids passing Earth in a certain distance but nobody gives you a feeling of how close such an encounter is. Allow me to fill in this gap.

Say an asteroid passes in a distance x from Earth, the radius of which we will call r. We now can ask how likely it is that an object that hits a disk of radius r+x also hits a disk of radius r provided that it any point on the larger disk is hit with equal likelihood.

The likelihood then is p = A(r)/A(r+x) where A is the area of a disk of the given radius, In other words p = πr²/π(r+x)² = 1/(1+x/r)². If we now define ξ=x/r (which is the distance in units of Earth's radius we get a quite simple formula: p = 1/(1+ξ)².

Using ξ is advantageous as it is a value you actually find in tables. Let’s try a couple of values; LD means Lunar distance and is the distance in terms of the average distance between Earth and Moon:

Distance in		ξ	p in %
LD	km
1.65614	636619.77	100	0.098
0.49684	190985.93	30	0.104
0.16561	63661.98	10	0.826
0.04968	19098.59	3	6.250
0.01656	6366.20	1	25.000
0.00497	1909.86	0.3	59.172
0.00166	636.62	0.1	82.645
0.00050	190.99	0.03	94.260
0.00017	63.66	0.01	98.030

Please note that the closer an encounter is the less meaningless this rough estimate becomes as the asteroid by no means randomly hits the disk of radius r+x but follows a clearly determined path.

Send in the Copyright Demolition Squad!

A video detailing what a scientist faces if he wants to publish a scientific article made me share some short, rather polemic thoughts on copyright on Google+. I then realized that they are worth being put on this blog. So here we go:

It is a well-established lie that copyright is a means for creators of art, music, scientific papers and other works to protect their intellectual property against people who want to prey on it. Little could be farther from truth. Copyright is regularly and habitually being perverted into a means to dispossess creators of their intellectual property so that they do not obtain a fair payoff.

In my opinion, those who fight the ever worsening, dreadful state of copyright are no enemies of the authors. They surely are enemies of those parasites who prey on these authors' works but fighting this vermin definitely is a just cause.

Joe Scientist comes face-to-face with
the scientific publication business

Polar Sea Ice Coverage

I added a page illustrating the current polar (i.e. Arctic and Antarctic) sea ice overage to my blog. It was originally located elsewhere. The information is provided by the National Snow and Ice Data Center. The diagrams show the ice concentration in the polar regions, the regions covered by polar sea ice and how the area with an ice density of 15 percent or higher varies.

Some like it hot

The current prediction for climate change by 2100 is that we are heading for an increase in temperature of 6 Kelvin (6 degrees Celsius or 11 degrees Fahrenheit). And here are some short National Geographics videos outlining an increase in temperature of 1 through 6 Kelvin

Could Just One Degree Change the World?

2 Degrees Warmer: Ocean Life in Danger

3 Degrees Warmer: Heat Wave Fatalities

4 Degrees Warmer: Great Cities Wash Away

5 Degrees Warmer: Civilization Collapses

6 Degrees Warmer: Mass Extinction?

The deadly touch of the ice stalactite

An ice stalactite or brinicle (brine icicle) is the undersea equivalent of a stalactite or icicle. They form beneath sea ice when a flow of extremely cold, saline water is introduced to an area of ocean water.

BBC Nature: ‘Brinicle’ ice finger of death filmed in Antarctic

The video is the first ever recording of the formation of an ice stalactite and not only shows its beauty but also its deadly power. More at the BBC’s site.

Hall effect for pedestrians

Professor Bowley explains the Hall effect, which involves electric current and magnetic fields.

Hall Effect - Sixty Symbols

Crowded Skies

I knew that there is quite a number of artificial satellites in space but I did not know how annoying they can be for people photographing stars. Take a look at this Sixty Symbols video introducing the Deep Sky Videos youtube channel.

Spy Satellites (from Deep Sky Videos)

“Made Easy” Errata

Nobody is perfect so it should not come as a surprise that the Made Easy videos are not free from mistakes. Here come the errata videos:

ERRATA

Errata 2

The Scientific Method Made Easy

This Made Easy video provides a very nice explanation of how the scientific method works

The Scientific Method Made Easy

For the above video I use LiveLeaks because the youtube video is not available in Germany due to the German pain in the ass called GEMA.

How to properly arrange arrays of wind turbines

Researchers at Caltech say that the power output of wind farms can be increased by an order of magnitude (i.e. at least tenfold) simply by optimizing the placement of turbines.

Modern wind farms usually employ propeller-like horizontal-axis wind turbines (HAWTs). The design has the disadvantage that the wake generated by one turbine can interfere with neighboring turbines thereby considerably reducing the energy that is produced. Therefore the individual turbines are placed farther apart than the obvious requirement of their blades not being able to touch dictates.

Alltwalis Wind Farm, Wales by Statkraft on Flickr
License: CC BY-NC-ND 2.0

Bigger blades and taller towers allow to use more of the wind and to do so at heights where gusts are more powerful but this results in higher costs, more challenging engineering problems and a larger impact as bigger and taller turbines generate more noise and are more dangerous to birds and bats.

The solution the researchers suggest is using vertical-axis wind turbines (VAWTs) (think of egg-beaters sticking out of the ground) can be positioned very close to one another and optimize their arrangement. Having every turbine turn in the opposite direction of its neighbors also increases their efficiency. Here is a video illustrating how the arrangement looks like:

Caltech Field Laboratory for
Optimized Wind Energy (FLOWE)

In the following video, John Dabiri, the Caltech professor of aeronautics and bioengineering who suggested the design of the wind farm, himself explains what fish schools have to do with it.

Caltech Researchers Find 
Wind-turbine Placement Produces
10-fold Power Increase

More on this:

• Wind-turbine Placement Produces Tenfold Power Increase, Caltech Researchers Say
• Biological Propulsion Laboratory at CALTECH [Wind Energy Research]

Human Evolution and Ancestry

Now comes a post that to some people people may be a red rag. It is two video about human evolution and how we all are descendants of Africans.

Human Evolution Made Easy

For the above video I use LiveLeaks because the youtube video is not available in Germany due to the German pain in the ass called GEMA.

Human Ancestry Made easy

How evolution works

The following two videos from the Made Easy series explain how evolution works. The first one deals with natural selection, as this mechanism is central to evolution – note that the full title of Darwin’s famous book is “On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life,” while second one presents evidence for the actual process of evolution.

Natural Selection Made Easy

The Theory of Evolution Made Easy

Note that the chicken displayed as a thumbnail for the second video is very fitting. Believe it or not: chickens are the closest living relatives of the much-feared T. Rex (so if someone asks how T. Rex steaks may taste like, the best guess is “tastes like chicken”).

The Age of Our World Made Easy

This Made Easy episode deals with the question how old Earth is and the scientific evidence that it was not created around 4004 BC.

The Age of Our World Made Easy

The Story of the Earth Made Easy

This Made Easy video explains how scientific understanding of geological formations and the processes leading to them grew over time.

The Story of the Earth Made Easy

The Origin of Life Made Easy

A video from the Made Easy series dealing with the origin of life.

The Origin of Life Made Easy

The History of Our Universe Made Easy

Two videos from Potholer54 on the history of our universe and how scientists little by little learned about it.

The History of Our Universe Made Easy, Part 1

The History of Our Universe Made Easy, Part 2

Cosmic rays causing global warming

A video by potholer54 on fact (what a certain scientific article actually says) and fiction (what certain blogs report it says).

Are cosmic rays causing global warming?

Simply Explained: 2011 Nobel Price in Physics

Physics Nobel Prize 2011 - Sixty Symbols: “Studying supernovae and the accelerating universe - and a bet over a bottle of whisky. It's our take on the 2011 Nobel Prize in Physics, won by Saul Perlmutter, Brian P Schmidt and Adam G Riess.”

Physics Nobel Prize 2011 - Sixty Symbols