Cassini discovered Saturn’s moons Tethys and Dione on March 21, 1864

On March 21, 1864, the Italian mathematician, astronomer, and engineer Giovanni Domenico Cassini (8 June 1625 – 14 September 1712) discovered Saturn’s moons Tethys and Dione. Cassini used a refractor telescope with an aperture of 108 mm to make this observation. Today’s (March 21) story of what happened this day in Science, Technology, Astronomy, and Space …

A large solar storm can knock out the internet and electricity. Here’s how

On September 1 and 2, 1859, telegraph systems around the world failed catastrophically. The operators of the telegraphs reported receiving electrical shocks, telegraph paper catching fire, and being able to operate equipment with batteries disconnected. During the evenings, the aurora borealis, more commonly known as the northern lights, could be seen as far south as …

Giotto spacecraft made the closest approach to Halley’s Comet on March 13, 1986

On March 13, 1986, European Space Agency‘s (ESA) Giotto spacecraft made the closest approach to Halley’s Comet at a distance of 596 kilometers (370 miles). Today’s (March 13) story of what happened this day in Science, Technology, Astronomy, and Space Exploration history.

ISS Transiting Moon over the Apollo 11 landing site! [Amazing video]

Astrophotographer Andrew McCarthy published on his Twitter account an amazing video of the International Space Station (ISS) transiting the Moon, over the landing site of Apollo 11, the first moon landing mission. Such an incredible amount of human achievement is represented in just one short video!

Solar Eclipse Calculator: a nice tool by NASA

Today I learned that there’s a solar eclipse calculator on the NASA website. Its official name is JavaScript Solar Eclipse Explorer (JSEX). Using this solar eclipse calculator, you can compute the local circumstances for every solar eclipse visible from a city for any century from -1499 to 3000 (1500 BCE to 3000 CE).

When did we first realize that Saturn had rings

Before the invention of the telescope, no one on Earth knew that Saturn had rings until the 1600s. Galileo Galilei discovered them with his telescope in 1610, but he did not know what these were either. Thus they remained a mystery until 1655 when the Dutch astronomer Christiaan Huygens (see notes 1) figured out that they …