Astronomy: Exploring Time and Space - Week 4

The Tools of Astronomy Telescopes Gallileoscope 1 inch diameter over 400 years ago, modern telescopes now have diameters of 8 or 10 meters. Telescopes can also be used in invisible light wavelengths, e.g. ultraviolet, infrared, radio. James Webb Space Telescope will bring space astronomy to the level of large ground telescopes, 6.5 meter mirror. Ground based telescopes cost about a billion dollars. Hubble Space Telescope cost about $6-8 billion.
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Gravitational Waves Detected

An exciting announcement last week marked another milestone in our understanding of the universe. Almost 100 years ago Albert Einstein predicted the existence of gravitational waves, or ripples in the fabric of space-time. The existence of gravitational waves had been confirmed for the first time in the late 1970s, but they were not able to detect them and prove their existence here on Earth. Not until last week: scientists were finally able to directly observe ripples of gravitational waves.
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KaTeX, Khan Academy's Math Typesetting Library

Khan Academy has published the fastest typesetting library for the web. IntMath’s KaTeX and MathJax comparison demo shows some impressive performance improvements. The demo page took 177 ms to process on my laptop. The MathJax version on the other hand took 4777 ms. The performance comes at a price that not everything is supported in KaTeX (yet). I wish aligned equations were supported, but I can live with it. Until I run across more serious problems I’ll happily use KaTeX instead of MathJax.
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How to stop a hanging Windows service

Windows processes and services can be controlled with the task manager, but occasionally I found hanging processes that required a reboot. Windows has some useful command line tools that could help avoiding a reboot and save some time: 1) Open command line prompt (cmd) as Administrator 2) Find process id with sc queryex {servicename}, e.g. sc queryex Apache2.4. You can also use tasklist|find "{executable}", e.g. tasklist|find "httpd" 3) Kill the process with taskkill /f /pid {PID}, e.
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Celephaïs

My first website used to be hosted on celephais.com, named after a short story by H.P. Lovecraft. I can’t believe it’s been 15 years now since I walked my first baby-steps on the web. I used the domain for a site dedicated to my favorite artists, musicians, authors, and movies - well, it was pretty much the unfinished sandbox of a site you’re looking at now, but built with static html files and a lot of graphics in a golden/brass 3d-look with lots of image maps.
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Zequals and the Art of Estimation

This Numberphile video is about Zequals which can be useful if you need to compute a quick estimate, for example to find out if your calculation is on the right track. The idea is to ruthlessly round every number to just one significant digit. For example: 3 * 7 = 21 zz 20 7 * 8 = 56 zz 60 436 * 68 zz 400 * 70 = 28000 zz 30000 The actual answer is 29648 and surprisingly close to the zequal-result.
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Sergei Prokudin-Gorskii

I read an article about Sergei Prokudin-Gorskii who created a number of stunning color photos over a hundred years ago. He was a chemist born in Russia in 1863 who studied in St. Petersburg, Berlin and Paris. He developed a process in which three black and white pictures were taken of an object in quick succession. One picture was taken with a red-filter, one with a blue, and another with a green filter.
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Breakpoint 2008

I can’t believe it’s been more than a year since I wrote about the Breakpoint demo event. Breakpoint 2008 already took place last March on the Easter weekend, so the following is actually pretty old news. I still want to share some of my favorites though. This year’s motto of the competition was Digital Garden hinting at the annual Garden Show in Germany that took place in Bingen at the Rhine river as well.
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Breakpoint 2007

I just read an interesting article about the Breakpoint 2007 demo-party that took place last April in Bingen on the Rhine river in Germany. Breakpoint is considered one of the biggest demoscene parties worldwide. For those who haven’t heard anything about demos yet, here’s a brief history as I remember it: The Beginnings It all started in the 80s with home computers like the Commodore 64 or Amiga, back when we used to share floppy disks and tapes with our favorite games.
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