How much do you really know about global warming?

Most likely you've already read (at least) a couple of news articles and seen a few TV shows tackling the subject of climate change. Probably you've even watched Al Gore's movie. But how much do you really know about global warming?
Information tends to be buried deep in scientific papers that usually address only narrow topics, and news articles are often unreliable or imprecise. Fortunately, a valuable resource has just been made available by the IPCC (Intergovernamental Panel on Climate Change). After 6 years of work, and involving more than 2500 expert scientific reviewers, 800 contributing authors and 450 lead authors from 130+ countries, the panel is publishing its "Climate Change 2007" assessment report, which focuses on three main areas: 1) the basics, 2) the impacts and 3) the mitigation possibilities.
Here are the links for the documents available for download at this moment:

No registration is necessary and all the documents can be downloaded completely free of charge. The final version of the IPCC Climate Change 2007 report is currently being distributed to all the member countries, who have already reviewed, agreed to and approved its content. This report is simply a must-have for anyone who would like to get all the facts about global warming!

Shot Spotter

The city of Oakland, in California, has recently installed a system called "ShotSpotter" that uses acoustic sensors scattered (and hidden) throughout the city to pinpoint the exact location from which gun shots are fired. Within seconds, the system automatically issues an alert over the police network, including information such as an aerial photo of the area, the time and place the incident occurred, and the number of shots fired.
This may sound like a complicated system, but in fact it is based on an extremely simple (yet brilliant) idea that cleverly applies a couple of concepts that have been known for hundreds of years: triangulation and acoustic location. Basically, whena gunshot is fired, the three closest sensors detect the sound, the direction it's coming from and the precise time, and the information is used to triangulate the shot location. The figure above illustrates how ShotSpotter works (click image for more details).

The key components of the sensors comprising the system include a microphone, a GPS receiver and a network connection that constantly sends information over to a central server. More information about the sensors is available here, as well as in this article. The system was developed by this company, and is currently being implemented in several cities across the US. For a flash animation (with sound) illustrating how ShotSpotter works, click here.

Just for the sake of curiosity, you may like to know that Leonardo da Vinci is believed to be the first person ever to propose the use of sound for object detection and location purposes. In 1490, he observed: "If you cause your ship to stop and place the head of a long tube in the water and place the outer extremity to your ear, you will hear ships at a great distance from you." Incidentally, that was about 200 years before the first mathematical theory of sound propagation was published (by Newton in 1687) and more than three centuries before the speed of sound in water was accurately measured (in 1826)! [more info here]
Later acoustic location became a very important tool and found application in several different areas. One of the most famous examples of acoustic location is the sonar. This site presents an interesting overview of the history and application of acoustic sensors, including several "curious" devices like the ones illustrated below... :)

Famous Geoglyphs Around the World: a Google Earth Tour

This video shows a "virtual satellite tour" of some of the most amazing geoglyphs on Earth. Some of these ground drawings or sculptures were made as early as 3000 years ago and measure up to 4200m [13,800ft] long! More details are presented in the video.


Here's a list of all the geoglyphs featured in the video:

  • Sultan the Pit Pony (Wales)
  • Atacama Giant (Chile)
  • Uffington White Horse (England)
  • Area 51 Bomb Target (NV, USA)
  • Nazca Lines (Peru)
  • Firefox Logo (OR, USA)
  • Coca-Cola logo (Chile)
  • Alton Barnes White Horse (England)
  • Folkestone Horse (England)
  • Pintados Geoglyphs (Chile)
  • Chiza Geoglyphs (Chile)
  • Long Man of Wilmington (England)
  • Cerne Abbas giant (England)
  • Barnsley Crop Circles (England)
  • Darfield Crop Circles (England)
  • Marree Man (Australia)
  • Ciudad Juarez White Horse (Mexico)
  • Blythe Geoglyphs (CA, USA)
  • Traditional Tibetan Mantra (China)
I made the video using Google Earth (probably you've figured that out already) and Fraps. The music is "Mars from The Planets", performed by the BBC Symphony Orchestra (1999).
For more info on geoglyphs, see this Wikipedia entry.

Cheers,
M.

Seeing is believing; or is it?

Can you believe what you see? Is whatever you see "real" or "true"? Do you see exactly the same as I do, or as anybody else does? Even if so, does your brain correctly interpret what your eyes (claim to) see?
These may sound like simple or even silly questions at first, but as the examples below illustrate that's not quite the case.
Look at the two images below, for instance (click figures to enlarge). You may be inclined to believe that the height of the gentleman's hat (distance C-D) is larger than its width (distance A-B). In fact, however, distance A-B is slightly larger than C-D! Similarly, on the second figure it may appear that line A-B (ceiling height) is longer than C-D (closet height). That's not the case either! Both lines have exactly the same length. Feel free to measure them if you like...



Now look carefully at the figure below. It certainly looks like the edges are curvy, right? Sorry, as you probably have guessed that's another optical illusion. All the edges in this image are completely straight! You don't need to believe me. If you still trust your eyes better, go grab a ruler or print it out to verify.


It gets trickier. Take a moment to inspect the checkerboard shown in the next figure. Which square is darker, A or B? Square A is obviously darker, correct? Not so, squares A and B are exactly equal, they have exactly the same color! This one is particularly hard to believe, but in this case our own eyes are playing us. I actually measured the RGB values using Photoshop, and for both squares they are 120-120-120. Still not completely convinced? Click here to see the proof.


As if it weren't enough that our spatial perception could be so easily messed up, we can now see that our perception of colors doesn't seem that good either. Another great example of this is illustrated below. This figure shows a negative picture of a Monarch butterfly, and on mouse-over is displays a grayed version of the same picture. Stare at the center of the negative image for about 30 seconds, then roll the mouse over the figure. What do you see?


Amazing, isn't it? Instead of the gray figure, we see a full color version of the Monarch butterfly, even though we are, in fact, looking at a grayscale picture. Try again if you're not fully convinced. The longer you wait before rolling the mouse over, the more vivid the effect is.

Finally, here's one more cool figure. Take a look at the three faces below.


Images A and B look OK, while image C looks horrible, right? What's the big deal? Look more closely (click to enlarge), and you'll see that figures B and C are in fact the same, not A and B. Our brain does not "complain" when we're looking at figure B because, even though the head is turned upside down, the mouth and eyes are still facing "up" as we'd normally expect. As you see, we were fooled once again! This example is presented in the book "Quirkology" by Richard Wiseman. Click here for more info on the "curious science" of quirkology!

The first three optical illusions shown above are from the website Archimede's Lab, which presents tons of other cool illusions as well as mind and visual puzzles. Similarly, the blog Optical Illusions Etc, from where the checkerboard and butterfly examples were borrowed, has lots of amazing figures and definite proof that we really cannot trust anybody, not even our own eyes!!!

Around The World in Eight Minutes: a Virtual Satellite Tour

Now for the first real post. This is a video I created not long ago using Google Earth and Fraps. It is a "World Tour" across 28 different locations spanning 6 continents. The list of places featured in the video follows below.



List of places:
1) San Francisco, CA
2) RMS Queen Mary, Long Beach, CA
3) Grand Canyon, AZ
4) Empire State Building, New York
5) CN Tower, Canada
6) Eiffel Tower, Paris, France
7) Hamburg, Germany
8) London Eye, England
9) Lisbon, Portugal
10) Saint Peter's Square, Vatican
11) Palacio Real, Madrid, Spain
12) Red Square, Moscow, Russia
13) Roman Colosseum, Italy
14) Forbidden City, China
15) Great Wall of China
16) Imperial Palace, Japan
17) Sydney, Australia
18) Taj Mahal, India
19) Baghdad, Iraq
20) The Pyramids, Egypt
21) Ngorongoro Crater, Tanzania
22) Buenos Aires, Argentina
23) Rio de Janeiro, Brazil
24) Christ The Redeemer, RJ
25) Brasilia, Brazil
26) Mexico City, Mexico
27) Google Campus, CA
28) SF Bay Area, CA

The intro song is "For He's A Jolly Good Fellow" from the original trailer of the film "Around the World in 80 Days" (1956). The background music is "Around the World In 80 Days", played by the BBC Concert Orchestra (Choice Film Soundtracks Cuts, Vol.1).

The tour is also available at the Google Earth Community webpage. Feel free to download it and explore the sites at your own pace on Google Earth!

Enjoy! ;-)
M.

First Post

OK, so let's try this blogging thing. This is my first post, ever. This space, as the name implies, is meant to be a repository of a few selected, random things found on the web or elsewhere.
I have several ideas but no specific plans for the blog at this time. Basically I intend to make it fun, with lots of interesting "casual bytes" about a wide variety of topics, ranging from silly jokes to news highlights, cool videos, funny images, generalities and whatever issues may come up at the time.
Initially I plan to post something every week or so, but as I mentioned this is a first experiment, so we'll see how things actually turn out.
Please feel free to send me your comments and suggestions!
Cheers,
M.