Interesting facts about Space.

The current topic we are studying in our Units of Inquiry (UOI), The Final Frontier, relates to space. Our first inquiry point, Contents of Space, has been extremely informative and interesting as it has allowed us to learn more about spatial objects such as planets and stars in our Solar System, the asteroids, meteors, black holes, comets, the Sun and moons.

Before studying this UOI topic, I was not aware of a lot of facts about space. For instance, I did not know that shooting stars were actually meteors or comets. I was also unaware of black holes or that the planets in our solar system had their own moons. Also, the fact that our solar system is just one of several solar systems in space was a big surprise. I had heard of the planets, but did not know that each planet was so different in weight, gravity, composition, mass and atmosphere.
Another interesting fact is that stars grow in size and at some point become Super Novas (or giant stars). Super Novas may explode to form black holes and other smaller stars.

The solar system that we are living in is called the Milky Way. This is because the stars and planets in the solar system appear to be white (as milk) mainly due to the light from Sun. Sun is the biggest and brightest star (Super Nova) in our solar system and has the strongest gravity. Other planets revolve around the Sun in well defined orbits. The planets around the Sun (from nearest to farthest) are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and the dwarf planet, Pluto. The time taken by each planet to revolve around the Sun varies, with the planets closer to the Sun having shorter orbits.

The Solar System consists of the Sun and the other bodies bound to it by gravity. Our Solar System consists of eight planets, their 166 known moons, three dwarf planets (Ceres, Pluto, and Eris and their four known moons), and billions of other small bodies. This last category includes asteroids, Kuiper belt objects, comets, meteoroids, and interplanetary dust.
Six of the eight planets are in turn orbited by natural satellites, usually termed "moons" after Earth's Moon, and each of the outer planets is encircled by planetary rings of dust and other particles. All the planets except Earth are named after deities from Greco-Roman mythology. The three dwarf planets are Pluto, the largest known Kuiper belt object; Ceres, the largest object in the asteroid belt; and Eris, the largest of the three which lies in the scattered disc.

The planets vary in size, weight and mass, composition, atmosphere and gravity. Each planet has its own orbits and satellites revolving around the planet in orbits. For instance, Earth has one satellite in its orbit, called The Moon. Each satellite has two forms of movement, the Rotation and the Revolution. The satellites rotate in their own axis, and revolve in the planet’s orbit. While the time taken for a satellite to rotate and revolve usually varies, the Earth’s Moon is the only satellite in our Solar System that takes the same amount of time to complete a rotation and a revolution. The Earth’s Moon takes 27 days, 7 hours and 43 minutes to rotate in its axis and the same amount of time to complete one revolution in Earth’s orbit. The Earth is the only known planet in our Solar System that is livable by humans. Our scientists have learnt a lot about the other planets and stars in our Solar System by sending space shuttles that gather scientific information about those planets for use in studies.

The term planet is an ancient one having ties to history, science, myth, and religion. The planets were originally seen as a divine presence; as emissaries of the gods. Even today, many people continue to believe the movement of the planets affects their lives, although this is rejected by the scientific community. The planets were initially thought to orbit the Earth in circular motions; after the development of the telescope, the planets were determined to orbit the Sun, and their orbits were found to be elliptical. As observational tools improved, astronomers saw that, like Earth, the planets rotated around tilted axes and shared such features as ice-caps and seasons. Since the dawn of the space age, close observation by probes has found that Earth and the other planets share characteristics such as volcanoes, hurricanes, tectonics and even hydrology.

Mercury is the closest planet to the Sun, and has an appearance similar to the Earth’s Moon. It orbits around the Sun every 88 days. Mercury has no natural satellites (or Moons) of its own. This planet has a lower gravity than Earth, and therefore an object that weighs 100 kgs on Earth would be just 38 kgs on Mercury.

Venus is the second closest planet to the Sun and takes about 224.7 days to revolve around the Sun. Venus is often called Earth’s “sister planet” as these planets are quite similar in size, gravity and composition. The planet has a very thick atmosphere consisting mainly of Carbon Dioxide and some Nitrogen. Venus takes the longest time to complete a rotation, 243 days. Its gravity is 0.91 times that of Earth. So an object that weighs 100 kgs on Earth would be about 91 kgs on Venus.

The Earth is the third closest planet to the Sun. The Earth has only one natural satellite which is the Moon, The Earth takes approximately 365 days to make one complete revolution around the Sun.

Mars is the fourth planet from the Sun in the Solar System. The planet is named after Mars, the Roman god of war. It is also referred to as the "Red Planet" because of its reddish appearance as seen from Earth. Mars is a planet with a thin atmosphere, having surface features reminiscent both of the craters of the Moon and the volcanoes, valleys, deserts and polar ice caps of the Earth. It is the site of, the highest known mountain in the solar system, and of the largest canyon. In addition to its geographical features, Mars’ rotational period and seasonal cycles are likewise similar to those of Earth. This is the reason that there has been much research done by Scientists to determine if there is indeed life like we have on Earth on Mars too.

Jupiter is the fifth planet from the Sun and the largest planet within the solar system. It is two and a half times as big as all of the other planets in our solar system combined. Jupiter, along with Saturn, Uranus and Neptune, is classified as a gas giant. Together, these four planets are sometimes referred to as the Jovian planets. The planet was known by astronomers of ancient times and was associated with the mythology and religious beliefs of many cultures. The Romans named the planet after the Roman god Jupiter.

Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Along with the planets Jupiter, Uranus, and Neptune, it is classified as a gas giant (also known as a Jovian planet, after the planet Jupiter). It was named after the Roman god Saturnus, equated to the Greek Kronos (the Titan father of Zeus) and the Babylonian Ninurta. Saturn's symbol represents the god's sickle. The day in the week Saturday gets its name from this planet.

Uranus is the seventh planet from the Sun and the third-largest and fourth-most massive planet in the solar system. It is named after the ancient Greek deity of the sky Uranus, the father of Kronos (Saturn) and grandfather of Zeus (Jupiter). Uranus was the first planet discovered in modern times. Though it is visible to the naked eye like the five classical planets (Mercury, Venus, Earth, Mars & Jupiter), it was never recognized as a planet by ancient observers due to its dimness. Sir William Herschel announced its discovery on March 13, 1781, expanding the known boundaries of the solar system for the first time in modern history. This was also the first discovery of a planet made using a telescope. Uranus and Neptune have internal and atmospheric compositions different from those of the larger gas giants Jupiter and Saturn. As such, astronomers sometimes place them in a separate category, the "ice giants". Uranus' atmosphere, while similar to Jupiter and Saturn in being composed primarily of hydrogen and helium, contains a higher proportion of "ices" such as water, ammonia and methane, along with the usual traces of hydrocarbons. It is the coldest planet atmosphere in the Solar System.

Neptune is the eighth and furthest planet from the Sun in the Solar System. It is the fourth largest planet by diameter, and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 14 Earth masses and less dense. The planet is named after the Roman god of the sea. Its astronomical symbol is a stylized version of Poseidon’s trident. Neptune's atmosphere is primarily composed of hydrogen and helium along with traces of methane. The methane in the atmosphere, in part, accounts for the planet's blue appearance, but because Neptune's colour is much more vivid than that of Uranus, which has a similar amount of methane, another component is presumed to contribute to Neptune's intense colour. Neptune also has the strongest winds of any planet in the Solar System.

Pluto also designated 134340 Pluto, is the second-largest known dwarf planet in the Solar System and the tenth-largest body observed directly orbiting the Sun. Originally known as a planet, Pluto is now considered the largest member of a distinct region called the Kuiper belt. Like other members of the belt, it is composed primarily of rock and ice and is relatively small: approximately a fifth the mass of the Earth's moon and a third its volume. It has an eccentric orbit that takes it sometimes closer & sometimes farther from the Sun. As a result, Pluto occasionally comes closer to the Sun than the planet Neptune does. Pluto and its largest moon, Charon, are often treated together as a binary system & Pluto has two known smaller moons, Nix and Hydra, discovered in 2005. From its discovery in 1930 until 2006, Pluto was counted as the Solar System's ninth planet. In the late 20th and early 21st centuries, however, many objects similar to Pluto were discovered in the outer solar system, notably the scattered disc object Eris, which is 27% more massive than Pluto. On August 24, 2006 the IAU defined the term "planet" for the first time. This definition excluded Pluto, which the IAU reclassified as a member of the new category of dwarf planets. After the reclassification, Pluto was added to the list of minor planets and given the number 134340.

Astronomy is a very active field of science that focuses on Space and Solar Systems. The telescope was first invented by the Galileo in 1609. Ever since, the telescope has been improving to enable scientists to study space with more powerful and clear images. The most advanced telescope today, The Hubble Space Telescope, is a large, space-based observatory which orbits around the Earth. It has the ability of capturing images of our entire Solar System as well as that of remote galaxies and other Solar Systems.

While telescopes offer a means of exploring our Solar Systems, scientists and engineers have also developed artificial satellites and space shuttles to allow for more advanced exploration of Space. Space shuttles today have the ability of transporting astronauts to remote planets so as to enable them to get a “first hand” view of the planets in our Solar System. Neil Armstrong was the first man to walk on the moon. Astronauts these days travel routinely to distant planets in our Solar System and can spend several days in the Space Shuttle. Artificial satellites are also launched into the Earth’s orbit to allow for the recording of images of our planet and other planets in our Solar System.

Space - The Planet Mercury

Space provides information on - satellites, stars, the Sun, planets and more.

The planet Mercury is the first planet in Space. It is the second smallest and also the fastest in its orbit. Mercury orbits very close to the Sun at a distance of only about 36 million miles. Mercury appears from a distance in manyways, similar to the Moon.

Mercury was the god of commerce, travel and thievery in Roman mythology. The planet was named Mercury by the Greek because it seemed to move quickly across the sky.

Mercury has 176 days of light and 176 days of darkness. There are no natural satellites. By radar observation from Earth evidence of water ice is present in the planet Mercury.

Mercury has a small magnetic field whose strength is about one percent of Earth's magnetic field. Mercury often is visible from earth with binoculars and sometimes even the naked eye. However, the planet is always very near the Sun and difficult to see in the twilight sky. Mercury 's orbit is tilted by seven degrees compared to that of earth.At its coldest the surface of mercury is seven times colder than a deep freeze.

When a meteorite strikes mercury 's surface, the impact punches a saucer- shaped crater in the ground. A wall of rock is thrown up all around it.Debris is blasted out in all directions ,creating smaller craters and long streakes in the ground. Because mercury has no weather,the features remain undistrubed.

Mercury, the densest of all the planets apart from Earth, has a huge metal core made of iron and nickel, surrounded by a relatively thin rocky shell.