Orionid Meteor Shower This Weekend

The Orionids

This weekend, from Saturday night into Sunday morning (10/21-10/22), you may observe the annual Orionid meteor showers streaking across the sky. Dozens of meteors will scorch the sky every hour.(Of course, the sky must be clear and dark, which, unfortunately, is not for me.) Fortunately, the moon is only in its crescent phase, so its light does not interfere with observing the meteor shower. The Orionid meteor shower happens every year in late October when Earth cross through debris left by Halley’s comet. Halley’s comet last passed through our solar system in 1986, and will not come back until 2061. When Halley’s comet neared the Sun, the heat melted the comet to form gas and dust. Though the comet leaves the solar system, that gas and debris continues to orbit the Sun. Most of the particles that form meteors are only the size of a few grains of sand, but comets have high kinetic energy as they hit Earth’s atmosphere— over 50,000 miles per hour! As the grains, or debris meteoroids, contact Earth’s atmosphere, they ionize molecules in the atmosphere, forming a bright trail across the sky known as a meteor or shooting star. Small meteoroids burn up in Earth’s atmosphere. A meteoroid must be bigger than the size of your fist to survive and hit Earth’s surface. Meteorites are usually found in deserts or Antarctica, where their black coloration stick out easily against the ground. Most meteorites land in the ocean, so no harm done there! In fact, 800 meteorites heavier than 100 grams strike the Earth every day; during meteor showers the frequency is higher.

Orionids Crossing Betelgeuse

Blazin’ Facts

  • Why “Orionid”? The meteors seem to intersect at Betelgeuse in the Orion constellation (but it’s just an optical illusion).
  • The Orionids historically have only produced 20 meteors at its peak, but in the last decade, scientists have observed more than 60 meteors per hour!
  • Meteors travel in space; meteoroids fall though the atmosphere; meteorites strike the surface
  • Did you know Halley never saw Halley’s comet? Halley suggested that the comet spotted in 1682 was the same one in 1531 and 1607. Halley’s observations led to the conclusion that comets orbit the sun. In 1705, he predicted the comet would appear in 1758, but died before he actually saw the comet.
  • Aside from Orionids, the other annual meteor shower is the Eta Aquarids that peaks early May.

References

Pereira, Pablo. “Meteor Shower Created by Halley’s Comet Peaks Tonight.” FOX News. FOX News, 20 Oct 2012. Web. 21 Oct 2012.

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The 8 Planets: A Series

The Solar System

When you look at the sky on a clear night, what do you see? Stars twinkling, constellations rising, or perhaps a cow jumping over the full Moon? We can clearly see stars light years away, yet through even a telescope stars are only pinpoints of light. But is every bright point of light a star?

Some of the bright pinpoints of lights we see are actually the planets of our solar system. While we may only see 1 or 2 planets with the naked eye, we may observe the distinct features of planets through a telescope. The reddish coloration of Mars. The rings of Saturn. Jupiter’s four biggest moons Io, Europa, Ganymede, and Callisto. But how can you tell whether they are planets or stars? Stars twinkle. Planets do not because they reflect sunlight. Most planets appear brighter than stars. Or… you could whip out your handy-dandy Google Sky Map app or any other sky map app!

That we are looking at the same sky our ancestors did over the last thousands of years is spectacular. Though pollution many have obscured some objects from our view, the sky has changed very little. From a dark area, we can still see what the hunter-gatherers saw!

To the observer, the local objects like the planets are intermixed among the infinite stars. But what mysteries are the eight planets hiding? How is each planet unique? How many moons does each planet have? What are their histories? I hope to explore the planets from every angle, for these planets are our home (Earth) and our neighbors (all planets except Earth). Eight posts in the near future will be dedicated to the eight planets. Each planet will be explained and unraveled. Let the journey through the solar system begin!

The Celestial Sphere

The Sun and stars show regular patterns of motion that reflect the rotation of the Earth around its North- South axis and the revolution of the Earth around the Sun. The motions show how the Solar System works — that indeed, the heliocentric “sun-centered” is true.

FRAMES OF REFERENCE: An observer can see half the celestial sphere at any given time, or 6 of 12 constellations. On Earth at any given time, different observers see different parts of the sky, and different motions of starts in their sky. This proves that Earth is a sphere that rotates once per day.

Twelve Constellations of the Ecliptic

CONSTELLATIONS: Constellations are groups of stars forming a pattern or an outline, such as Scorpius (Scorpion), Ursa Major (The Bear), Cygnus (The Swan), and Orion (The Hunter). Constellations in the circumpolar zone are close to the North Celestial Pole and stay up all night and year round, while those in the equatorial zone are near the Celestial Equator and changes during the night and year. An asterism is a sub-group of a constellation, such as the Big Dipper in Ursa Major. The twelve constellations of the zodiac (of the ecliptic) appear during certain months of the year: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces.

The Celestial Sphere

THE NIGHT SKY: While stars “twinkle,” planets do not; planets only reflect light from stars. Stars appear to twinkle because light passes through Earth’s atmosphere and different pockets of air at different temperatures.

MAGNITUDE: In the original magnitude system, 1 is the brightest visible and 6 is the faintest visible. The difference of 5 magnitudes (6-1=5) is actually a factor of 100 in magnitudes. A magnitude 6 star is 100 times fainter than a magnitude 1 star. The modern system differs from the original one, with some stars brighter than magnitude 1 stars and others fainter than magnitude 6 stars. Human eyes respond to light logarithmically: m= -2.5log(b), where b = brightness of star by counting the number of photons per second.

ANGULAR MOVEMENTS & MEASURING WITHOUT A TELESCOPE: The width of your finger held at arm’s length equals 1 degree, while the width of your fist equals 10 degrees (e.g. full moon is about the width of half a finger, or 0.5 degrees).

1 revolution = 360°

2∏ radians = 360°

1° = 60 arcminutes = 60′

1′ = 60 arcseconds = 60”

1° = 60′ x 60°/1′

1° = 3,600”