On May 29, 1919, Einstein’s General Theory of Relativity, which was just four-year-old at the time, was put to its first test during a total solar eclipse. Albert Einstein’s prediction of the bending of light by the gravity of the Sun, one of the components of his general theory of relativity, could be tested by …
Category Archives: Solar System
Earth passed through the tail of Halley’s Comet on May 19, 1910
On May 19, 1910, the Earth passed through the tail of Halley’s Comet. Prior to the date, using spectroscopy, astronomers detected cyanogen, a very deadly poison in the comet’s tail. This caused panic. French astronomer Camille Flammarion (26 February 1842 – 3 June 1925) even claimed that life on Earth would end because of this.
Neptune’s Moon Nereid was discovered on May 1, 1949
On May 1, 1949, Neptune’s Moon Nereid was discovered by the Dutch astronomer and planetary scientist Gerard Kuiper, who is the eponymous namesake of the Kuiper belt. Nereid is also named Neptune II because it is the second moon of Neptune to be discovered. It is also the last satellite of Neptune to be discovered …
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Halley’s Comet made the closest approach to Earth on April 11, 1986
On April 11, 1986, with about 63 million kilometers (39 million miles), Halley’s Comet made its closest approach to Earth on its outbound journey (while moving away from the Sun).
The first moon in orbit around an asteroid (243 Ida) was discovered on March 26, 1994
On March 26, 1994, a photo was released showing the first moon discovered be in orbit around an asteroid, 243 Ida. Today’s (March 26) story of what happened this day in Science, Technology, Astronomy, and Space Exploration history.
Christiaan Huygens discovered Titan on March 25, 1655
On March 25, 1655, the Dutch mathematician, physicist, astronomer, and inventor Christiaan Huygens discovered Titan, Saturn’s largest moon and the second-largest natural satellite in the Solar System (after Jupiter’s Ganymede). Today’s (March 25) story of what happened this day in Science, Technology, Astronomy, and Space Exploration history.
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 …
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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.
Earth Phases as seen from the Moon
Earth’s phases in the Moon’s sky are exactly the opposite of the Moon’s phases in the Earth’s sky. Is there a full moon? The Earth is dark in the Moon’s sky. It’s half-moon? The Earth is also half. Moon is a slim crescent? Earth is almost full.
Can you see an astronaut on the Moon via a strong telescope? No, here’s why
As NASA plans to return to the moon, will we be able to see the astronauts on the Moon via a really strong telescope, when they were landed?
