On May 9th 2016 the planet Mercury will briefly be visible from Earth as a tiny dot moving slantingly across the lower part of the solar surface. Mercury is smaller than Earth, but not so much as to not give an idea of what the relative size of the Earth to the Sun would be. I recommend everyone who has a chance to do so to observe this phenomenon through binoculars duly equipped with professional welding glass protection -- your local retailer of cameras, telescopes and binoculars should have them. To gaze straight into the sun with the naked eye is dangerous. Imagine then to do the same through a set of binoculars! Below a photo from Mercury's last passage in front of the Sun as seen from Earth in November 2006. Now, it's not the dot to the left (a sun spot) but the tiny speck at about five o'clock from the solar center!
And just to put that in its proper galactic perspective: this is the (estimated) relative size of the Sun itself compared to the hot blue giant Deneb in the constellation Cygnus, a very bright, distant star, but clearly visible to the naked eye in the northern hemisphere throughout the entire summer. Just think of it for a moment...
By the way, it's by the minute diminution of the light emitted from a star caused by a transiting planetary body, as perceived along the line of vision between the Earth and that star, that astronomers are able to discover and determine some of the characteristics pertaining to such distant wanderer. The astronomical instrument capable of detecting such infinitely fine fluctuations in emitted star light has aptly been named Kepler (after the famous astronomer who, based on Tycho Brahe's observational data, proved that planet orbits must be elliptical) and is to be found constantly orbiting the Earth above its atmosphere. Allegedly, Kepler's unique mission is to detect planets orbiting other stars in the Milky Way, and eventually, hopefully, tantalise us with the illusive prospect of another Earth-like planet within our galaxy.
And just to put that in its proper galactic perspective: this is the (estimated) relative size of the Sun itself compared to the hot blue giant Deneb in the constellation Cygnus, a very bright, distant star, but clearly visible to the naked eye in the northern hemisphere throughout the entire summer. Just think of it for a moment...
By the way, it's by the minute diminution of the light emitted from a star caused by a transiting planetary body, as perceived along the line of vision between the Earth and that star, that astronomers are able to discover and determine some of the characteristics pertaining to such distant wanderer. The astronomical instrument capable of detecting such infinitely fine fluctuations in emitted star light has aptly been named Kepler (after the famous astronomer who, based on Tycho Brahe's observational data, proved that planet orbits must be elliptical) and is to be found constantly orbiting the Earth above its atmosphere. Allegedly, Kepler's unique mission is to detect planets orbiting other stars in the Milky Way, and eventually, hopefully, tantalise us with the illusive prospect of another Earth-like planet within our galaxy.
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