Earth is the third planet from the sun and the fifth largest
in the solar system in terms of size and mass. It is the densest of all the
planets, having density equal to 5513 kilogram per cubic meter. Earth is the
only planet in the solar system not named after a mythological being. Instead,
its name is derived from the Old English word "ertha" and the
Anglo-Saxon word "erda" which means ground or soil. Earth was formed somewhere around 4.54 billion years ago and
is currently the only known planet to support life - and lots of it.
Earth Planet Profile
Equatorial Diameter: 12,756 km
Polar Diameter: 12,714
km
Mass: 5.97 x 1024 kg
Moons: 1 (The Moon)
Orbit Distance: 149,598,262 km (1 AU)
Orbit Period: 365.24 days
Surface Temperature: -88 to 58°C
Earth is the only
planet not named for a mythological God or Goddess
The other seven planets in the solar system were named after
Roman gods or goddesses. For the five visible to the naked eye, Mercury, Venus,
Mars, Jupiter and Saturn they we named during ancient times. This Roman method
was also used after the discovery of Uranus and Neptune. Although word “Earth”
comes from the Old English word “ertha”, meaning ground or land, which
sometimes worship as the goddess in Hinduism.
The Earth was once
believed to be the Centre of the Universe
For 2000 years ancient astronomers believed that the Earth
was static and had other celestial bodies travelling in circular orbits around
it. They believed this because of the apparent movement on the Sun and planets
in relation to their viewpoint. In 1543, Copernicus published his Sun-centered
model of the Solar System which put the Sun at the Centre of our solar system.
Earth is the densest
planet in the Solar System
The density of Earth differs in each part of the planet, the
core, for example, is denser than the Earth’s crust, but the average density of
the planet is around 5.52 grams per cubic centimeter. Which makes earth the
densest planet of the solar system.
The Rotation of the Earth
is gradually slowing down
Recent discoveries has shown that he deceleration of the
Earth’s rotation is very slow, approximately 17 milliseconds per hundred years.
Eventually this will lengthen our days but it will take around 140 million
years before our day will have increased from 24 to 25 hours.
Earth’s Atmosphere
Earth’s atmosphere is composed of 78% nitrogen, 21% oxygen,
and trace amounts of other gases including argon and carbon dioxide. While 70%
of earth’s surface is covered with water. The remainder consists of continents
and islands which together have many lakes and other sources of water.
Earth has a powerful
magnetic field
The Earth is like a great big magnet, with poles at the top
and bottom near to the actual geographic poles. The magnetic field it creates
extends thousands of kilometers out from the surface of the Earth – forming a
region called the “magnetosphere“. Scientists think that this magnetic field is
generated by the molten outer core of the Earth, where heat creates convection
motions of conducting materials to generate electric currents. Be grateful for
the magnetosphere. Without it, particles from the Sun’s solar wind would hit
the Earth directly, exposing the surface of the planet to significant amounts
of radiation. Instead, the magnetosphere channels the solar wind around the
Earth, protecting us from harm.
The Day of Earth is
Not 24 Hours
It actually takes 23 hours, 56 minutes and 4 seconds for the
Earth to rotate once completely on its axis, which astronomers refer to as a
Sidereal Day. Now wait a second, doesn’t that mean that a day is 4 minutes
shorter than we think it is? You’d think that this time would add up, day by
day, and within a few months, day would be night, and night would be day.
But remember that the Earth orbits around the Sun. Every
day, the Sun moves compared to the background stars by about 1° – about the
size of the Moon in the sky. And so, if you add up that little motion from the
Sun that we see because the Earth is orbiting around it, as well as the
rotation on its axis, you get a total of 24 hours.
This is what is known as a Solar Day, which – contrary to a
Sidereal Day – is the amount of time it takes the Sun to return to the same
place in the sky.
A year on Earth isn’t
365 days
It’s actually 365.2564 days. It’s this extra .2564 days that
creates the need for a Leap Year once every four years. That’s why we tack on
an extra day in February every four years.
The Gravity between
the Earth and the Moon causes the tides on Earth
This effect on the Moon means it is tidally locked to Earth.
Its rotation period is the same as its orbit time so it always presents the
same face to Earth.
The Earth has an
Ozone Layer which protects it from harmful solar radiation
This shell is a special type of oxygen that absorbs most of
the Sun’s powerful UV rays. But recently scientist shows that the ozone layer
is being continuously damaged by global warming.
Hi there, I'm a Young 18 Years Old Engineering Student who...
No comments:
Post a Comment