The Lyrids meteor shower
The Lyrids bring an end to the meteor shower drought that exists during the first few months of the year. On April 22nd, the shower is predicted to reach its peak, offering skygazers an opportunity to witness up to 20 bright, fast-moving meteors per hour which leave long, fiery trails across the sky, without any specialist equipment. The name Lyrids comes from the constellation Lyra - the lyre, or harp - which is the radiant point of this shower, i.e. the position on the sky from which the paths of the meteors appear to originate. In the Northern Hemisphere Lyra rises above the horizon in the northeast and reaches the zenith (directly overhead) shortly before dawn, making this the optimal time to observe the shower.
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Lyra is a prominent constellation, largely due to Vega which forms one of its corners, and is one of the brightest stars in the sky. Interestingly, Vega is defined as the zero point of the magnitude scale - a logarithmic system used to measure the brightness of celestial objects. Technically, the brightness of all stars and galaxies are measured relative to Vega!
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Have you ever wondered why meteor showers occur exactly one year apart and why they always radiate from the same defined point in the sky? The answer lies in the Earth's orbit around the Sun, which takes 365 days. During this time, Earth may encounter streams of debris left by a comet, composed of gas and dust particles that are released when an icy comet approaches the Sun and vaporizes. As the debris particles enter Earth’s atmosphere, they burn up due to friction, creating a streak of light known as a meteor. Meteorites are fragments that make it through the atmosphere to the ground.
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The reason that the Lyrids meteor shower peaks in mid-late April each year is that the Earth encounters the same debris stream at the point on its orbit corresponding to mid-late April. Comets and their debris trails have very eccentric, but predictable orbits, and the Earth passes through the trail of Comet Thatcher in mid-late April every year. Additionally, Earth’s orbit intersects the trail at approximately the same angle every year, and from the perspective of an observer on Earth, the constellation Lyra most accurately matches up with the radiant point of the meteors when they are mapped onto the canvas of background stars in the night sky.
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The Lyrids meteor shower peaks in mid-late April each year. Image/ EarthSky.org
This year, there is a fortunate alignment of celestial events. New Moon occurs on April 20th, meaning that by the time the Lyrids reach their maximum intensity, the Moon is only 6% illuminated, resulting in darker skies and an increased chance to see this dazzling display.
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Written by Joseph Brennan