Space-Time basic of the Universe

Seleaninews (Inspired by Stephen Hawking and Einstein) move into the actual technology of education and align the practicing approach of the Universe realities in the Space-Time curve. We draw here the basic you need to know for better understanding coming stages. You will find at the end of the article, a practical Questionaire that you can answer within commenting here itself,or through our www.twitter.com/msalimali page, or by email to seleaninews-at-seleani.com.

The Night Sky

During the day there is only one star that can be seen in the sky. It is the star that is closest to us, the star that has the most effect on our daily lives and for which we have a special name: the Sun.
The Moon and the planets do not shine on their own. They appear bright at night because the Sun lights them up.
In the night sky there are a few objects that can be seen which are not stars – the Moon and the planets, like Venus, Mars, Jupiter of Saturn.
All the other shining dots in the night sky are stars, like our Sun. Some are bigger, some are smaller, but they are all stars. With a naked eye, on a clear night, away from sources of light like cities, we can see hundreds of them.

Our Moon

A Moon is a natural satellite of a planet.
A Satellite is an object that goes around a planet, like the Earth goes around the Sun, and natural means that it is not man-made.
The average distance of the Moon from the Earth is 238,854 miles (384,399 kilometres).
The Moon circles around the Earth in 27.3 days.
There is no atmosphere on the Moon, so the sky there is black, even during the day.

Light and Stars

Everything in our Universe takes time to travel, even light.
In space, light always travels at the maximum speed that is possible: 186,000 miles per second (300,000 km per second). This speed is called the speed of light.
Our Sun is further away from us than our Moon is.
When light leaves the Sun, it takes about 8 minutes and 30 seconds to reach us on Earth.
Distances in space can be measured in terms of light-years, which is the distance light travels in one year. A light-year is almost 6,000 billion miles (around 9,500 billion km).

Particles

Elementary particles are the smallest possible things that cannot be divided up into smaller particles. Examples include the electrons, which carry electricity, and the photon, which carries light.
An atom is not an elementary particle because it is made of electrons going around a nucleus in the centre, like the planets go around the Sun. The nucleus is made of protons and neutrons packed tightly together.

Matter

Matter is made of atoms of various types. The type of atom or element, as it is called, is determined by the number of protons in the nucleus. This can be up to 118, with an equal or greater number of neutrons.
The simplest atom is hydrogen, whose nucleus contains just one proton and no neutron.
The largest naturally occurring atom, uranium, has a nucleus that contains 92 protons and 146 neutrons.
When atoms join together in chains, the resulting object is called a molecule.

Comets

Comets are big, dirty and not very round snowballs that travel around the Sun.
They are made up of elements created in stars that exploded a long time before our Sun was born.
The largest known comets have a central core of more than 20 miles (32km) from one side to the other.
We have seen only about 1,000 comets so far, but it is believed that there are more than 100 billion of them, very far away from the Sun, waiting to come closer to us.

The Solar System

The Solar System is the cosmic family of our Sun. It comprises all the objects trapped by the Sun’s gravity: planets, dwarf planets, moons, comets, asteroids and other small objects yet to be discovered.
The closest planet to the Sun is Mercury (36 million miles away on average).
The furthest planet from the Sun is Neptune 2.8 billion miles away on average).
Number of planets in the Solar System is 8. From closest to the Sun, the planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
Number of dwarf planets in the Solar System is 3 – Ceres, Pluto and Eris.
Number of known planetary moons is 165. Jupiter has 63, compared to Earth’s 1.

Neutron Stars

When stars much more massive than the sun run out of fuel, they usually expel all their outer layers in a giant explosion called a supernova. Such an explosion is so powerful and bright it can outshine the light of billions of stars put together.
Sometimes the core of the star can remain behind as a ball. This remnant is very hot: around 180,000 degrees Fahrenheit (100,000 degrees Celsius).
The pressure is so intense inside these balls that they become liquid inside, surrounded by a solid crust about a mile (1.6km) thick. The liquid is made of particles that normally remain inside the core of the atoms – the neutrons – so these balls are called neutron stars.

Temperature

Average temperature on Earth’s surface: 15 degrees Celsius (59 degrees Fahrenheit)
Lowest temperature ever recorded on Earth: -89°C (-128.2ºF), Vostok, Antarctica, 21st July 1983.
Highest temperature ever recorded on Earth: 58°C (136.4°F), Al ‘Aziziyah, Libya, 13th September 1922.
Temperature on the surface of the Moon: Daytime average: 110°C (230°F), Night-time average: -150°C (-240°F).
Average temperature at the core of the Sun: 15,000,000°C (27,000,000°F).
Average temperature of space: -270.4°C (-457.72°F).

Practical Quiz to answer