Lunar Eclipse

Lunar Eclipses, the lesser known of the eclipses, is when the Earth moves between the Sun and our Moon. 

The shadow of the Earth can be split into 2 defined sections: the Umbra and the Penumbra. Within the Umbra, directly behind the Earth in line with the Sun, there is no direct solar radiation (there is no sunlight). There are 8 main phases of the Moon, and Lunar eclipses only occur during full moon.



Upon the event of a lunar eclipse, astronomers classify the specific eclipse according to a scale, the Danjon scale. Level 0 of the Danjon scale is a very dark eclipse, with the moon almost invisible. Level 1 is dark eclipse grey or brownish in colour and details are made out with great difficulty. Level 2: Deep red or rust-coloured, level 3: Bright red eclipse and level 4: very bright copper red or orange. It is a beautiful site to behold, and many astronomers or even the average man in the street eagerly await the next eclipse. The last eclipse that we observed was on the 25th of May 2013, and the next is on Friday the 18th of October 2013. It shall reach full eclipse at 23:51 UTC (same as GMT). Totality can last from half an hour to an hour. 

Earth Fact File

There are three key features that distinguish Earth from any other planet we have discovered, these are:

 

 

1.Its atmosphere is composed of mainly oxygen and nitrogen. Water is present in its 3 states, liquid water covering roughly 70% of the Earth’s surface. It is home to life in all its diverse forms

 

2. Contrary to popular belief, the Earth is not spherical, as it is flattened at the poles by 42km, making it an oblate spheroid. Although there are still a small amount of people who believe the Earth is flat, there is a completely overwhelming amount of evidence that proves that it is spherical. A few of the reasons are 

 

• Ships disappear over the horizon 
• Satellites orbit the Earth – impossible if it was flat 
• The curvature of the Earth’s shadow is visible during a partial lunar eclipse 
• We have pictures

3. The Earth’s polar axis is titled by 66.5 degrees to the plane on which it orbits the sun (the ecliptic plane). This means the sun lies directly above the equator on only two dates of the year – the spring and autumnal equinoxes. These occur on the 21st of March and the 22nd/23rd of September.

 

 

Light Pollution

When astronomers are observing the night sky sometimes their observations are hindered by light pollution, specifically skyglow. At night time a lot of light wastefully shines up into the night sky, most of this light comes from urban areas such as towns and cities where lights that are unnecessarily bright or are poorly designed so that they direct upwards, this means faint stars, distance nebulae and the Milky Way cannot be observed using a telescope.
 

This picture shows that in a rural town stars are more easily observed than in a metropolitan area where there is a lot of light pollution, this is because in urban built-up areas there are more lights which make the sky brighter. Light Pollution is a serious problem that affects astronomers all over the world, light pollution used to be solved by moving telescopes to rural areas but as more people move to rural areas, less land is available, the amount of light pollution increases and the amount of sky we can see decreases. 

Increasingly, rural areas are also beginning to become polluted with lights; this means the countryside which was the most ideal place to view stars is becoming less and less useful. The BBC said that only 1/10th of the country enjoy a truly dark sky. Whereas, in the 1950’s, most of us would be able to see the Milky Way. However, our vision is now being gradually more obscured by the result of further urbanisation and development coupled with inefficient and undesirable lighting.

With the increase in light pollution more people are electing to send their telescopes into space, this means not only are they avoiding light pollution they can also get clearer pictures because the telescopes are unhindered by clouds and other things.

In 1989 the British Astronomical Association Campaign for Dark Skies, was set up to represent the interests of people who care about the night sky, this was for both astronomers and non-astronomers. The CfDS campaign against excessive, inefficient and irresponsible lighting and work with organisations and local authorities to improve lighting in their village. CfDS can be contacted at http://www.britastro.org/dark-skies/index.html

James Lovell - Apollo 13 Commander

"I have seen the Earth as it truly is... a grand oasis in the vastness of space" - Jim Lovell



Jim Lovell's Official NASA portrait (Source:http://en.wikipedia.org/wiki/File:Jim_Lovell_official_1966_portrait.jpg)

 

James "Jim" Arthur Lovell, Jr was born on the 25th of March 1928 in Cleveland, Ohio to a Czech mother, who promptly moved the family to Milwaukee, Wisconsin, where he graduated from Juneau High School and 'Eagle Scout'. His father died in a car accident when Jim was only a small boy. As a child, he was interested in rocketry, and built small flying models. He married Marilyn Gerlach in 1952and they have 4 children: Barbara, James, Susan and Jeffrey.

He is surprisingly one of the lesser known astronauts of the Apollo 11 mission, serving as a reserve commander for Neil Armstrong, despite his lengthy stay in space. In total, he has logged 29 days, 19 hours and 3 minutes in space, and is one of three to have been to the moon twice, and is the only one to have been there twice without landing. On the Apollo 13 mission, Lovell was part of the crew who piloted the module back to Earth after an oxygen cylinder exploded, leaving the ship with an extremely limited oxygen supply. By using the lunar module as a lifeboat, they used the 'free return trajectory' that they had left in orbit to return back to Earth, and thankfully they survived.

Captain Lovell was selected as an astronaut by NASA in September of 1962. He has since served as backup pilot for the Gemini 4 mission, and the background commander for the Gemini 9 flight, as well as the reserve commander on the Apollo 11 lunar landing mission, mentionned previously.

Jim Lovell, at the point of writing this post, is now 85 years of age. His career has taken him above and beyond, literally. Logging almost 30 days in space, and is the only one to have been to the moon twice without landing, he is certainly an astronaut to be remembered.

Astronomy Definitions

 ·         Oblate Spheroid- A sphere that is slightly flat on both poles due to the earth’s rotation. Spinning on its north-south axis.


·         Poles- they are two opposite points on a planet’s surface through which the planet’s axis passes.

Solar system- A system consisting of a group of planets or other bodies that orbit a star.

Solar System
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Horizon- the horizon is a point of apparent intersection between the land/sea and the sky as seen by the observer.

Horizon
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Latitude- the angular distance of a place north or south of the earth’s equator usually expressed in degrees.



Equinox-The date or time when the sun is directly above the equator, this is when both day and night are equal length.

Equator-Is an imaginary line on a planet that is equal distance from both poles. It divides the planet into the northern and southern hemisphere.

 The Ecliptic- Is the plane on which the earth orbits the sun. The earth's polar axis is tilted by 66 and a half degrees to reach this plane.

Earth's Atmosphere

Due to the increase in the different gasses in our atmosphere, the atmosphere is becoming more and more thinner and slowly merging with space at about 100 km. This boundary is known as the Stratosphere (Karman line). The atmosphere protects the earth from energetic X-rays as well as keeps the temperature at an average of 15 degrees. This is done by reflecting excess sunlight away from the earth.

BBC Bitesize

 

In basic terms the Earth's atmosphere protects the Earth from heating up and absorbing large amounts of different radiation such as x-rays, gamma rays etc. It also protects us from meteorites to an extent as when the meteorite enters the Earth's atmosphere most of the mass is burned reducing the size of the impact.
 

Gas:	Percentage in atmosphere:
Nitrogen	78%
Oxygen	21%
Argon	1%
Carbon dioxide (at present)	0.04%
Water vapour	1%

Features of the Moon

People who observe the moon usually notice two areas of the surface. One of these areas is dark-grey, and relatively smooth. These are the lunar seas often called Mares. These areas of dark grey are called the lunar seas because astronomers once thought that they were rich with water. They are actually iron-rich basaltic rock. The other areas of the moon people usually notice are the light-grey (the highlands) parts which have huge numbers of craters. These areas are made of anorthosite which is a rough-grained type of rock. Because the lunar seas are smoother, this implies that the seas are ‘younger’.

Many of the moons small craters have been made by meteoroids from around the solar system but the larger craters such as the Tycho crater and the Copernicus crater were made by asteroids.

There are some types of features on the moon such as craters, wrinkle ridges and rilles (grooves). Rilles are narrow channels in the lunar seas which can be straight or smoothly curved and are believed to have been caused by lava flows. Wrinkle ridges are caused by the buckling of the lunar surface as a result of compressive forces.