What's The Current Earth's Obliquity

 By: Adam Gregory
In the sector of astronomy axial tilt is also known as obliquity. The axial tilt is generally accepted to be the angle between the rotational axis and the line vertical to the orbital plane of an object. Now Earth's axial tilt is 23.4. The orbital plane of Earth is commonly known as ecliptic plane and the there's a different name for Earth's axial tilt 'obliquity of the ecliptic'.

This axis remains tilted in the same direction across the year. This means that when one hemisphere is indicating the sun during one half of the year then in the other 1/2 the other hemisphere will point towards the sun. This is the phenomenon behind the change of season. Whichever hemisphere is tilted towards the sun receives more amount of sunlight every day. Also at 12 noon the sunlight strikes at an angle which is closer to vertical, this results in more energy being received per unit area.

In Polar Regions the obliquity is really low this causes the Polar Regions to receive lesser solar radiation and the conditions become agreeable for the formation of glaciers. While at the regions close to the equator the axial tilt of the earth is bigger and therefore the daylight received is more in these regions. The Earth's axial tilt isn't a fixed quantity. It keeps changing and the cycle has a time period of approximately 41,000 years.

The awareness of Earth's axial tilt is very essential for making astronomic calculations and making findings from the outer surface of the Earth. In the 10th century, Abu Mahmud Khojandi measured the Earth's axial tilt. He made the measurements using the principle with a giant sextant. He discovered that the value of the tilt was lower than those measured by earlier astronomers ; he so concluded that the Earth's axial tilt isn't a continued quantity.

The earth's axial tilt varies between 22.1 and 24.5. At present the tilt is decreasing. In addition to this steady decline in the value of the tilt there are 1 or 2 smaller short term divergences. These are known as nutations and are principally caused by the changes in the plane of the orbit of the moon. This phenomenon can change Earth's axial tilt by about 0.005 degrees in plus or minus.

The four seasons that we experience are a result of the Earth's axial tilt. Together with the earth's revolution around the sun the seasons are also caused by the axial tilt of the earth.

At the end of the nineteenth century Simon Newcomb worked out the Earth's axial tilt and found that the value is 23 27' 8.26". This worth was accepted until improved telescopes were developed. These telescopes authorized more correct observations to be made. The electronic computers allowed more elaborate models to be made which could enable better and more exact calculations. In the year 1976 Lieske developed an updated model which had an axial tilt equal to twenty-three 26' 21.448". This model has become a part of the estimation formula that has been advised by the World Astronomical Union in the year 2k.
loading...
Author:
Artice Source: http://www.articlesphere.com
Article Tags: earth, planet, world, obliquity, tilt

Related Articles in Science


People interested in the above article are also interested in the related articles listed below:

Archaeoastronomy is the study of how folks in the past accepted the phenomenon occurring in the sky, how they utilised the phenomenon and what part the sky played in the culture of these people. Archaeoastronomy can be said to be closely associated the historical astronomy. It is also related with the historic records of heavenly events which can often be used to answer astronomic Problems.
There are lots of predictions depending on which on 21st December 2012 the world will end. This date is meant to mark the end of a cycle of the Mesoamerican long count calendar which is alleged to be just about a 5125 years old cycle. Some people interpret the import of this date differently and say this date will mark the beginning of some changes and transformations.
Most of the time, people turn on an electric gadget in their homes and do not think twice about the electricity that flows through wires. Neither do they think about what it takes to control that electricity. Control of the electric current is achieved by making use of power relays. To simplify, these relays are electronically operated switches. They help to control power circuits.
loading...

More in Science

Excellent, Larry. Thank you for taking the new article directory technology and making it work to the max. I encourage everyone to keep contributing and contributing regularly. I can attest to the fact that this site is already a strong directory in a field of many. Kudos to Larry!

Matthew C. Keegan
The Article Writer

 

I find it a delight to use both as an author and a publisher. It is full of nice little surprises that make the whole process of writing, reading and publishing articles a complete delight. This is one that comes out tops and beats the rest hands down.

Eric Garner
Managing Director
ManageTrainLearn

 

I did a Google search and came across your site. It was exactly what I was looking for and was elated to find such a broad range of articles. As I am launching a free magazine in a small town in Florida, I wanted to be as resourceful as possible while still being able to provide some content that is interesting and well written. Your site has all the variables in the mix. Excellent Site hitting all the notes in the scale sort of speak.

Mo Montana
Florida, USA

Article Topics

 
Copyright © 2005 - by Larry Lim, Singapore - Article Search Engine Directory at ArticleSphere.com™
All Rights Reserved Worldwide. All Trademarks and Servicemarks are the property of the respective owners.
ArabicBulgarianCatalanChinese (Simplified)Chinese (Traditional)CzechDanishDutchEnglishEstonianFinnishFrenchGermanGreekHaitian CreoleHebrewHindiHungarianIndonesianItalianJapaneseKoreanLatvianLithuanianNorwegianPersianPolishPortugueseRomanianRussianSlovakSlovenianSpanishSwedishThaiTurkishUkranianVietnamese