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Tag Archives: Astronomy

M42: Inside the Orion Nebula

The Great Nebula in Orion, an immense, nearby starbirth region, is probably the most famous of all astronomical nebulas. Here, glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away. In the above deep image in assigned colors highlighted by emission in oxygen and hydrogen, wisps and sheets of dust and gas are particularly evident. The Great Nebula in Orion can be found with the unaided eye near the easily identifiable belt of three stars in the popular constellation Orion. In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries. These nurseries contain much hydrogen gas, hot young stars, proplyds, and stellar jets spewing material at high speeds. Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun.

Source: NASA Astronomy Picture of the Day

Comets Lemmon and PanSTARRS Peaking

Two impressive comets will both reach their peak brightness during the next two weeks. Taking advantage of a rare imaging opportunity, both of these comets were captured in the sky together last week over the Atacama desert in South America. Comet C/2012 F6 (Lemmon), visible on the upper left of the above image, is sporting a long tail dominated by glowing green ions. Comet C/2011 L4 (PanSTARRS), visible near the horizon on the lower right, is showing a bright tail dominated by dust reflecting sunlight. The tails of both comets point approximately toward the recently set Sun. Comet Lemmon will be just barely visible to the unaided eye before sunset in southern skies for the next week, and then best viewed with binoculars as it fades and moves slowly north. Comet PanSTARRS, however, will remain visible in southern skies for only a few more days, after which it will remain bright enough to be locatable with the unaided eye as it moves into northern skies. To find the giant melting snowball PanSTARRS, sky enthusiasts should look toward the western horizon just after sunset. Deep sky observers are also monitoring the brightening of Comet C/2012 S1 (ISON), which may become one of the brightest objects in the entire night sky toward the end of 2013.

Two comets appear in the sky at the same time. Unfortunately, it will be rainy and cloudy for the next few days, I really hope I still have a chance for a glimpse on Friday.
Source: NASA Astronomy Picture of the Day

Some Astromonical Definitions

Due to the recent cosmic coincidence, I found I (and probably some of people) am confused by some of the terms, so I looked up an astronomical glossary to find out what exactly they meant.

  • Asteroid:
    1. A small rocky body that orbits a star
    2. A small planet-like body of the Solar System
  • Meteor:
    1. Fragment or particle that enters the Earth’s atmosphere and is then destroyed through friction, becoming visible as this occurs as a momentary streak of light.
    2. A “shooting star” – the streak of light in the sky produced by the transit of a meteoroid through the Earth’s atmosphere; also the glowing meteoroid itself.
  • Meteorite:
    1. Object that enters the Earth’s atmosphere and is too large to be totally destroyed by friction before it hits the surface. Meteorites may in some way be connected with asteroids.
    2. A solid-body portion of a meteor that has reached Earth’s surface. Meteorites are divided into three main classes: aerolites (stony meteorites), siderites (iron meteorites), and siderolites (stony iron meteorites). Most meteorites are high-density objects related to asteroids.
  • Meteoroid:
    1. A small particle orbiting the Sun in the vicinity of Earth.

Source: CalTech Astronomical Glossary

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