Easy Science

What's so special about a supermoon? Turns out, it's a bit more subtle than it sounds—but for the interested observer, there's plenty to see. The name “supermoon” was coined by an astrologer in 1979 and is often used by the media today to describe what astronomers would call a perigean ( pear-ih-jee-un ) full moon: a full moon occurring near or at the time when the Moon is at its closest point in its orbit around Earth. The term gives preference to the geometric alignment of Sun-Earth-Moon and allows the occurrence of perigee into a wider time period than the actual instant of perigee (up to about two weeks, which is almost half of the Moon’s orbit). For those looking carefully, there are several things worth noting. Take a look at the lunar images from November 2016 below: Which of these views of the Moon is a SuperMoon? Both! This is a size comparison of the Moon on the “supermoon” night of November 13-14, 2016. On the left, the Moon was nearer the horizon, ...

An  eclipse  happens when a planet or a moon gets in the way of the sun’s light. Here on Earth, we can experience two kinds of eclipses:  solar eclipses  and  lunar eclipses . What’s the difference? Solar Eclipse A  solar eclipse  happens when the moon gets in the way of the sun’s light and casts its shadow on Earth. That means during the day, the moon moves over the sun and it gets dark. Isn’t it strange that it gets dark in the middle of the day? This  total eclipse  happens about every year and a half somewhere on Earth. A partial eclipse, when the moon doesn’t completely cover the sun, happens at least twice a year somewhere on Earth. But not everyone experiences every solar eclipse. Getting a chance to see a total solar eclipse is rare. The moon’s shadow on Earth isn’t very big, so only a small portion of places on Earth will see it. You have to be on the sunny side of the planet when it happens. You also have to be in t...

The Earth’s axis is tilted by 23.4 degrees and so the plane of the Earth’s equator is tilted with respect to the plane of the Earth’s orbit around the Sun – sometimes referred to as the ecliptic. This means that during the Northern Hemisphere summer, the Sun illuminates the Northern Hemisphere more than the Southern Hemisphere. During this time we receive more hours of sunlight and the longest day is known as the summer solstice. During the winter, the Sun illuminates the Southern Hemisphere more than the Northern Hemisphere because the North Pole is titled away from the Sun. During this time we receive fewer hours of sunlight and the shortest day (and longest night) is known as the  winter solstice . But at two points in the year the Sun will illuminate the Northern and Southern Hemispheres equally – these are known as the equinoxes: the  autumnal equinox  in October and vernal equinox in March. It’s the moment in which the plane of Earth's eq...