Constellation

This article is about constellations of stars. See also: satellite constellation.

A constellation is a group of stars visibly related to each other in a particular configuration. In three-dimensional space, most of the stars we see have little relation to one another, but can appear to be grouped on the imaginary plane of the night sky. Humans excel at finding patterns and throughout history have grouped stars that appear close to one another into constellations. An "unofficial" constellation is also called an asterism. The stars in a constellation or asterism rarely have any astrophysical relationship to each other; they just happen to appear close together from Earth and typically lie very far apart in space.

The grouping of stars into constellations is essentially arbitrary, and different cultures have had different constellations, although a few of the more obvious ones tend to recur frequently, e.g Orion and Scorpius.

The International Astronomical Union (IAU) divides the sky into 88 official constellations with precise boundaries, so that every direction belongs to exactly one constellation. These are mostly based upon the constellations of the ancient Greek tradition, passed down through the Middle Ages.

The first 12 are the zodiac. In addition to these 12, Ptolemy listed another 36 constellations (which now count as 38, due to the break-up of Argo Navis). In more recent times this list has been added to, first to fill gaps between Ptolemy's patterns (the Greeks considered the sky as including both constellations and dim spaces between) and second to fill up the southern sky as European explorers journeyed where they could see it.

Other proposed constellations didn't make the cut, most notably Quadrans Muralis (now part of Boötes) for which the quadrantid meteors are named. Various other less official patterns have existed alongside the constellations called asterisms, such as the Big Dipper (known in the UK as The Plough) and the Little Dipper.

See also: list of constellations

Table of contents
1 Star names
2 See also
3 External links

Star names

Many stars are named using the genitive of the constellation in which they are found. These names include Bayer designations such as Alpha Centauri, Flamsteed designations such as 61 Cygni, and variable star designations such as RR Lyrae. For more information about star names, see Star designations.

See also

External links

zh-cn:星座/简 zh-tw:星座/繁


In the News

New Light Cast On Key Chemical Reactions In Interstellar Space
A detailed understanding of key chemical reactions that take place in interstellar space has been provided by new research. Scientists have developed a detailed understanding of the dynamics of reactions between neutral radicals and neutral molecules, known as ?neutral-neutral?reactions, at temperatures as low as 20 Kelvin, approximately the temperature of interstellar space.

Gore's Webby TV Network Debuts
Current TV, the channel Al Gore and his cohorts bought, launches Monday. Its utopian vision of being the sounding board for young people and broadcasting content produced by viewers will have to prove profitable.

Neural Stem Cell Study Reveals Mechanism That May Play Role In Cancer
In the dynamic world of the developing brain, neural stem cells give rise to neurons deep within the brain's fluid-filled ventricles. These newborn neurons then migrate along the stem cell fibers up to the neocortex, the seat of higher cognitive functions. Now, scientists have discovered a key mechanism of this migration -- one that may also play an important role in other developmental processes and diseases, including cancer.

Ocean acidification: 'Evil twin' threatens world's oceans, scientists
The rise in human emissions of carbon dioxide is driving fundamental and dangerous changes in the chemistry and ecosystems of the world's oceans, marine scientists warn. "Ocean conditions are already more extreme than those experienced by marine organisms and ecosystems for millions of years," the researchers say.

Solving The Mystery Of Mutated Proteins And The Brain
In some neurological diseases, too much of what is usually a good thing can be bad, said researchers at Baylor College of Medicine in a report in this week's issue of the journal Cell.Dr. Huda Zoghbi and her colleagues have determined that a genetic mutation actually enhances the normal activity of a protein, and in the case of ataxin-1, the disease spinocerebellar ataxia type 1 results.

Brit Film Future Is Digital
The U.K. Film Council wants to encourage people to see more specialty films and thinks installing high-tech projectors is the way to do it. By Jason Silverman.

New Research Shows How Evolution Explains Age Of Puberty
Children aged 10 and 11 are sexually mature, and neither they nor society are suitably prepared for the implications of that. This is the message of Professors Mark Hanson and Peter Gluckman, whose review of the evolution of puberty is published online this week in Trends in Endocrinology and Metabolism.

'Real Life' Study Clarifies Risk Of Recurrence For High-risk Breast Ca
High-risk breast cancer patients do not appear to have a higher risk of relapse than the general breast cancer population during the first two years after diagnosis, unless their cancer has spread to more than 10 axillary lymph nodes, Italian researchers reported today at the 2nd ESMO Scientific &Educational Conference (ESEC) in Budapest, Hungary.

What Recognizes What In Plant Disease Resistance?
How do plant resistance gene recognize the cognate pathogen? These authors dissect the interaction of a resistance gene and a viral pathogen.

New Technology Shows Our Ancestors Ate ... Everything!
Using a powerful microscope and computer software, a team of scientists from Johns Hopkins, the University of Arkansas, Worcester Polytechnic Institute and elsewhere has developed a faster and more objective way to examine the surfaces of fossilized teeth, a practice used to figure out the diets of our early ancestors.




MP3 Music Downloads

Preview songs, Download Free Music,Burn CDs at ITunes.com
iTunes_RGB_9mm

 


Google




InformationQuickFind.com - Find Information Fast

Links | Privacy Policy | News |