In 1992 mission STS-49 was the first flight of Space Shuttle Endeavour. Three astronauts are moving a 4.5 tonne communications satellite into the Shuttle’s cargo bay. The Earth in the background is covered with thousands of square miles of cloud. This was the first spacewalk involving three astronauts.
The International Space Station (ISS) is a habitable satellite orbiting the Earth at between 330 and 435km (205 to 270 miles). The ISS was assembled in space. The first component was launched in 1998 and by 2011 159 components had been added, taking over 1,000 hours of work.The first resident crew of Expedition 1 arrived in the year 2000 and the ISS has been permanently manned since then, the longest continuous human presence in space.The ISS is a research laboratory conducting experiments in biology, physics, astronomy, meteorology and others.It is the largest artificial body in orbit and can be seen by the naked eye.Go to https://spotthestation.nasa.gov/ to check when the ISS will next pass over you. NASA will even email you a reminder
This aurora over Earth was photographed from the International Space Station.Sometimes called the Northern and Southern lights, an aurora is formed when electrically charged particles from the Sun enter the Earth’s atmosphere. The particles collide with atoms of gas in the atmosphere and form light.
Everything we know in the universe started more than 10 billion years ago with a huge cosmic explosion called the Big Bang. There are about 100 billion galaxies in the visible universe. The spiral galaxy in which we live is called the Milky Way. Our Solar System is located on the Orion arm of the Milky Way and our Sun is one of a 100 billion stars in this one galaxy.
The Sun
The Sun is the 4.6 billion-year-old star at the centre of our Solar System and has a diameter of 1,392,000km (864,949 miles), about 109 times that of Earth. The Sun is made up of about 74% hydrogen and 25% helium, with the remainder being oxygen, carbon, neon, iron and others.
The visible surface of the sun, called the photosphere, is about 300km (186 miles) thick and its temperature is 5,500°C (10,000°F). Above the photosphere is the chromosphere, measuring about 10,000km (6,214 miles) in thickness, which sends jets of plasma out into space. The magnetic storms, or Aurora, that directly affect the Earth are due to chromospheric eruptions, which release large quantities of electromagnetic energy.
The average distance to the Earth from the Sun is 149,597,871km (92,955,807 miles), also known as 1 Astronomical Unit (AU). Light travels from the Sun to Earth in about 8 minutes and 19 seconds. Life on Earth is dependent on the light and warmth from sunlight.
Orbiting closest to the Sun are the four terrestrial inner planets. In order of their distance from the Sun these are as follows.
When a supergiant star runs out of fuel it creates a supernova.Gravity pulls the centre of the star inward very quickly and it collapses into a small ball. The gravity of a black hole becomes so strong that anything close to it gets pulled in, even light. They are called “black” because they absorb all light and nothing is reflected. This black hole was discovered by the Hubble Space Telescope.
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Mercury, the smallest planet and the closest to the Sun, is only slightly larger than Earth’s Moon. Mercury’s surface is very like the Moon, covered by mountainous regions and large basins full of craters. Its atmosphere is mostly hydrogen and helium. Its surface heats up and cools down very quickly, reaching 427°C (800°F) when it is closest to the Sun and falling to -179°C (-290°F) when it is farthest away.
Mercury travels around the Sun every 88 days in an oval-shaped orbit, taking it as close as 47,000,000km (29,000,000 miles) to the Sun. It travels at almost 50km (31 miles) per second which is faster than any other planet and that is why it is named after the Roman god Mercury, the winged messenger. The first spacecraft to visit and photograph Mercury was Mariner 10, followed several years later by the MESSENGER spacecraft.
Venus is the brightest heavenly body in our night sky after the Moon and has sometimes been called the morning or evening star. It is surrounded by a dense, cloudy atmosphere, consisting of mainly carbon dioxide and nitrogen, which reflects the sunlight. We cannot usually see through this cloudy layer but NASA’s Magellan mission to Venus used radar to take images of the surface. Venus is similar in size to the Earth, with an equatorial diameter of 12,104km (7,521 miles). Venus rotates in the opposite direction to the other planets, so on Venus the Sun rises in the west and sets in the east. Venus takes 225 days to orbit the Sun and 243 days to complete each rotation about its axis, making each day on Venus 117 Earth days long. Its surface is made up of volcanoes and plains, the two major plains being Ishtar Terra and Aphrodite Terra.
The Russian spacecraft Venera 13 landed on Venus but only survived for 127 minutes due to the immense crushing pressure and high temperature on the surface.
The planet Venus is named after the Roman goddess of love and beauty.
Our planet is completely unique in the Solar System. Other planets have atmospheres, seasons and weather but only Earth has life. Earth’s special position in the Solar System – the third planet from the Sun, orbiting at 149,597,871km (92,955,807 miles) – allows life to exist. Any slight change in this distance would be the end of life on our planet.
The Earth is 4.6 billion years old and has an equatorial diameter of 12,750km (7,922 miles). Earth’s axis of rotation is tilted by 23.45 degrees and this gives the planet its four seasons. For part of each year the Northern Hemisphere is tilted toward the Sun and enjoying summer. At the same time the Southern Hemisphere is tilted away from the Sun and is in winter. This then reverses every six months. In March and September both hemispheres have equal amounts of sunlight.
Nearly 70% of the Earth’s surface is covered in ocean and the water vapour in the atmosphere is responsible for most of the weather. The Earth’s atmosphere is mostly nitrogen and oxygen and this forms a layer protecting us from harmful solar radiation and from meteors.
Most of the planets were named after Roman gods and goddesses. However, the name Earth is an old English-German word which just means ground.
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The Moon is a 4.5 billion-year-old ball of rock in space and is Earth’s only natural satellite. The most likely theory about how the Moon was formed is called the Giant Impact Hypothesis. It is thought that a planet the size of Mars collided with the Earth and the resulting debris formed the Moon. As the Moon has no atmosphere it is constantly being bombarded by meteorites and so is covered in impact craters, some billions of years old. The changing faces of the Moon that we see from day to day are known as the Moon’s phases and these are dependent on which part of the Moon is being illuminated by the Sun as it orbits the Earth. In July 1969 Apollo 11 Commander Neil Armstrong became the first man to set foot on the Moon, with the famous words “That’s one small step for man, one giant leap for mankind.”
Jupiter is the fifth planet from the Sun and the largest planet in the solar system, at 1,335 times larger than the Earth.This image shows Jupiter and its four largest moons. Starting top right and moving clockwise they are Io, Ganymede, Callisto and Europa.Jupiter has 67 moons – the most of any planet in the solar system.The four largest moons were discovered by Galileo Galilei in 1610 and were named by Simon Marius in his book of 1614. Io is closest to Jupiter and is the most volcanic body in our solar system. It is thought that there may be twice as much water on Europa as there is on the Earth, with its icy surface covering a huge ocean.Ganymede is the largest moon in the solar system and is bigger than Mercury. It is the only moon to have its own magnetic field.
