Category Archives: astronomy

Quick reminders about the leap day

I explained the difference between the sidereal day and the solar day in a previous post (one of my popular posts). A sidereal year is the time taken by the Earth to orbit the Sun once with respect to the fixed … Continue reading

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Advanced LIGO is now listening to gravitational waves

Update: please see “Direct observation of gravitational waves by the Advanced LIGO” for the latest information. ********************************************************************************* When binary neutron stars collapse into a black hole or when black holes collide gravitational waves emerge from the center of those collisions. Supernovas … Continue reading

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Difference between the precession of the equinoxes and the precession of Earth’s axis

I mentioned in a previous post that there is confusion about the periodicities of the precession of equinoxes and the precession of Earth’s axis. The confusion may be arising because people think that these are the same phenomenon because they … Continue reading

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Mikolaj Kopernik

Today, I was on jury duty. At the entrance of the courthouse, right next to the x-ray machines there was a large commemorative plaque about Copernicus. I don’t know why it was there but I was very happy to see … Continue reading

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