發佈日期:2014年11月10日
2014 Geminids Forecast
This year the Geminids will peak during the night (starting at 9-10 p.m.) and early morning hours of 13 and 14 of December. You will want to view these meteors during the earlier part of the night as a quarter moon will rise around midnight.

Fast Facts
Origin: 3200 Phaethon (an asteroid or a possible "rock comet")
Radiant: constellation Gemini
Active: 4-17 Dec. 2014
Peak Activity: 13-14 Dec. 2014
Peak Activity Meteor Count: Approximately 120 meteors per hour
Meteor Velocity: 35 km (22 miles) per second
About the Meteor Shower
The Geminids, which peak during mid-December each year, are considered to be one of the best and most reliable annual meteor showers. The Geminids did not start out that way. The Geminids first began appearing in the mid-1800s. However, the first showers were not noteworthy with only 10 - 20 meteors seen per hour. Since that time, the Geminids have grown to become one of the most major showers of the year. During its peak, 120 Geminid meteors can be seen per hour.

The Geminids are bright and fast meteors and tend to be yellow in color. Geminids are also known for their fireball meteors. Fireballs are larger explosions of light and color that can persist longer than an average meteor streak. This is due to the fact that fireballs originate from larger particles of material. Fireballs are also brighter, with magnitudes brighter than -3.

Viewing Tips
The Geminids are best viewed during the night and pre-dawn hours and are visible across the globe due to a nearly 24-hour broad maximum. This shower is considered one of the best opportunities for young viewers since this shower starts around 9 or 10 p.m. To view the Geminids, find an area well away from city or street lights. Come prepared with a sleeping bag, blanket or lawn chair. Lie flat on your back with your feet facing south and look up, taking in as much of the sky as possible. After about 30 minutes in the dark, your eyes will adapt and you will begin to see meteors. Be patient -- the show will last until dawn, so you have plenty of time to catch a glimpse.

Where Do Meteors Come From?
Meteors come from leftover comet particles and bits from asteroids. When these objects come around the sun, they leave a dusty trail behind them. Every year the Earth passes through these debris trails, which allows the bits to collide with our atmosphere where they disintegrate to create fiery and colorful streaks in the sky.

The Asteroid
Unlike most meteor showers which originate from comets, the Geminids originate from an asteroid: asteroid 3200 Phaethon. Asteroid 3200 Phaethon takes 1.4 years to orbit the sun once. It is possible that Phaethon is a "dead comet" or a new kind of object being discussed by astronomers called a "rock comet." Phaethon's comet-like highly elliptical orbit around the sun gives credence to this hypothesis. However, scientists are not certain how to define Phaethon. When Phaethon passes by the sun it does not develop a cometary tail, and its spectra looks like a rocky asteroid. Also, the bits and pieces (2-3 gm/cc) that break off to form the Geminid meteoroids are also several times denser than cometary dust flakes (0.3 gm/cc).

3200 Phaethon was discovered on 11 October 1983 by the Infrared Astronomical Satellite. Due to its close approach to the sun, Phaethon is named after the character of Greek myth who drove the sun-god Helios' chariot. Phaethon is a small asteroid -- its diameter measures only 5.10 km (3.17 miles) across. It was astronomer Fred Whipple who realized that Phaethon is the source for the Geminid meteors.

The Radiant
Their radiant -- the point in the sky from which the Geminids appear to come from -- is the constellation Gemini, the "Twins." The constellation of Gemini is also where we get the name for the shower: Geminids. Note: The constellation for which a meteor shower is named only serves to aid viewers in determining which shower they are viewing on a given night. The constellation is not the source of the meteors. Also, you need not look only to the constellation of Gemini to view the Geminids -- they are visible throughout the night sky. https://solarsystem.nasa.gov/planets/...

Everything you need to know: Geminid meteor shower
http://earthsky.org/space/everything-...

2014 Geminids meteor shower
http://www.timeanddate.com/astronomy/...

Video clips credit ESO, ESA & NASA

Music credit: Must Be Something - Jingle Punks
YouTube Audio Library










發佈日期:2014年12月13日
雙子座流星雨,14號即將登場,預估1小時最多可看到120顆流星,14號晚上八點是­流星雨最大值,可以趁機觀賞,不過也提醒大家,出門要注意保暖,強烈大陸冷氣團持續影­響台灣,下一波寒流低溫,更會來到10度以下。完整內容 http://video.udn.com/news/247880 , FB http://www.facebook.com/udntv , Twitter https://twitter.com/udntv , G+ https://plus.google.com/b/10998063548...
 










 









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