Trackbacks

[...] Astro Guyz Book Review [...]
The Sky is Waiting.
[...] Astro Guyz Book Review [...]
The Current Number of Exoplanets Discovered is: 3755
Pictured is a Delta IV rocket launch from Cape Canaveral on November 21^{st}, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.
Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New. A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.
The Sun is our nearest star, and goes through an 11year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 201314.
Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.
Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a nearweekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.
Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.
A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth’s shadow is apparent in the image.
Copyright © 2018 · Education Theme on Genesis Framework · WordPress · Log in
Review: The Secrets of Triangles by Alfred S. Posamentier & Ingmar Lehmann.
Available for PreOrder Now!
This week, we delve into the fascinating world of mathematical geometry. Wait! Wait! Come back! We promise not to be too mathy for this week’s review… well, OK, I know that we say that during every math book review, but this time, we promise…
We’ll have to admit, our geometry expertise goes back to one grim math class in seventh grade. Just why mathematical and geometric proofs aren’t more widely taught is a mystery; I’ve heard many a mathophobe state that they actually did pretty well with geometry in school. In the Secrets of Triangles: a Mathematical Journey by Alfred S. Posamentier and Ingmar Lehman out in August from Prometheus Books, the authors delve into that seemingly innocuous threesided geometric form to release the mysteries within. Both mathematicians have collaborated previously on such mathematical odysseys as Pi: A Biography of the World’s Most Mysterious Number & The Glorious Golden Ratio, also recently reviewed on this site.
The authors do not assume any knowledge beyond that of High School geometry (whew!) and delve into some fascinating relationships springing from all that is threesided. Think you know your isosceles and equilateral triangles? Think again. Starting off with the famous Pythagorean theorem governing the relationship of the hypotenuse to the legs of a right triangle, the authors move on to the realm of golden triangles, Napoleon’s and Ceva’s Theorem governing triangles, and more. We were especially fascinated by the properties of a ninepoint circle created by a triangle embedded within a triangle and the properties of an equilateral triangle. Did you know, for example, that the sum of two distances from the two nearest vertices of a triangle to any point along a circle intersecting all three points of an equilateral triangle will equal the distance to the farthest vertex? Try it (we did) it’s the only place outside of an area of an equilateral triangle were such holds true. Astronomer and geometer Claudius Ptolemaeus (Ptolemy of the Almagest fame) knew of such a relationship.
The authors end with a fascinating look at fractals and the Mandelbrot set as relates to triangles. Did you know that selecting randomized points within an equilateral triangle after thousands of iterations, sketches out what’s known as a Sierpinski Triangle? Freaky stuff, this math is…
And where math goes, astronomy often follows. It’s hard not to see triangles galore as we probe star fields, and I often memorize patterns of successive lines and triangles of stars in an effort to pin down a faint astronomical target. Geometry is all around us, whether it be in the spiral of a flower or a galaxy. It’s often been said that math and science may be the universal language that we will share with extraterrestrial intelligence, but just how different might their math be? Keith Devlin makes a fascinating case for “alien math” and our perception of the universe in a recent SETI talk.
Do pick up The Secrets of Triangles for a fascinating look at the geometrical. While this may not be a “read on the beach” novel, it would prove to be an indispensible classroom companion for those wading into the fascinating subject for the first time.