The Solar System Topic 11

SUNSPOTS Sunspots are temporary phenomena on the photoshere of the Sun that appear visibly as dark spots compared to surrounding regions. Manifesting intense magnetic activity, sunspots host secondary phenomena such as cornonal loops (prominences) and reconnection events. We study the sunspots because they are a very good indicator of how active the Sun is. A large group of sunspot means that there may be other things and events going on as well, like flares and prominences. If two spots come together (it happened today! 17.December.2009) then they simply make one bigger spot. The main reason for observing sunspot activity, nowadays, is that it can interfere with power grids and sensitive equipment on board satellites. Sunspots appear in regions, and they can merge quite easily WITHIN their respective regions. However, there are only a few cases of regions merging. In most cases (>95%), regions do avoid each other. This is because they are magnetic. If two regions are north and south of each other, and in the same hemisphere, then there would be a rather distinct clear area between them. It is only when regions are end-on when the trailing spots of one can 'intermingle' with the leading spots of the other region, but this rarely happens. I can only think of two cases in the last 30 years.

SOLAR FLARE A solar flare is a sudden flash of brightness observed over the Sun’s surface or the solar limb, which is interpreted as a large energy release of up to 6 × joules of energy. They are often, but not always, followed by a colossal coronal mass ejection. The flare ejects clouds of electrons, ions, and atoms through the corona of the sun into space. These clouds typically reach Earth a day or two after the event. hey produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays, although most of the energy is spread over frequencies outside the visual range and for this reason the majority of the flares are not visible to the naked eye and must be observed with special instruments. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona.

PROMINENCES A prominence is a large, bright, gaseous feature extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona.

SOLAR STORMS Also known as a geomagnetic storm. A geomagnetic storm is a temporary disturbance of the Earth’s magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field which interacts with the Earth’s magnetic field.

Objects around the SUN

Eight PlanetsDwarf planetsMoons Asteroids and asteroid belt Meteoroids, meteors & meteorites Comets Kuiper Belt & Oort Cloud

Eight planets Needs to travel in an orbit. Almost spherical shaped Keep orbital path clear of other objects Inner rocky planets: Mercury, Venus, Earth and Mars. Other gas giants: Jupiter, Saturn, Uranus, Neptune. Dwarf planets Does not keep a clear path of other objects. Pluto is now classified as a dwarf planet. Other examples are: Eris, Ceres & Makemake

Moons This is a body that revolves around a planet. They do not have their own source of light, they reflect the sun’s light. Always move around the same planet. Asteroids & asteroid belt An asteroid is a rock found between the orbits of Mars and Jupiter. This area is called an asteroid belt. They have iron cores just like Earth.

Meteoroids, meteors & meteorites A meteoroid is a solid object that is smaller than an asteroid. When a meteoroid enters the Earth’s atmosphere it starts to burn up and is called a meteor – we call this a shooting star. Sometimes meteors crash into the ground before completely burning up. The remains are called meteorites.

Comets Made up of frozen gas and bits of rock. Come from the beyond the furthest planets. Three distinct parts: HEAD, COMA (outer circle of light) and TAIL (points away from the sun) Head of rock and frozen gas, melts and releases gas and dust. Kuiper belt & Oort Cloud Kuiper belt is beyond Neptune & is a ring of icy and rocky objects. Oort Cloud is even further away and is spherical.

Shape of the solar system It is disk shaped The Sun is at the centre of the solar system All the planets move in the same direction Planets and other objects are kept in their orbits by gravity. – The larger the mass of the objects the larger the gravity experienced.

Practical task Page 202 – On a separate piece of paper answer questions 1 – 8 of Part A. Make a spider summary of the eight planets including the following information: – Name, temperature, number of moons, rings, time taken for one day, time taken for one year, composition, size (diameter)& distance from the Sun.

Earth’s position in the solar system

Supporting life As far as we know, Earth is the only planet in our Solar System that can support life. At NASA the hunt for exoplanets (planets outside of our solar system), astronomers have been desperately searching for is another planet like Earth that’s capable of supporting life. Astronomers have found Earth-sized planets in other solar systems. They have found planets in the “habitable zone” (an orbit where temperatures would be potentially conducive to life) of other solar systems. But they haven’t found an Earth-sized planet in the habitable zone of another star…yet! – sized-planet/ sized-planet/ – scientists-hope.html scientists-hope.html

Temperature on Earth Distance from the Sun is the most important factor affecting temperature range. Atmosphere also plays a role. Earth is just the right distance from the Sun. – Average temp range is -40°C to 40°C.

Temperature & distance

Sunlight & the Food Chain Energy is produced in the Sun by the nuclear reactions. This energy is sent out (radiates) into space. This energy (heat and light) enables life on Earth in the following ways: – Sunlight is used by plants to produce food (photosynthesis). – Animals depend on this food and oxygen produced by plants. – Sunlight heats up parts of the Earth and creates winds and rain which is needed for life.

Water on Earth In Earth’s temperature range water can exist in all three states: – Liquid – ocean, lakes, rivers, swamps and underground. – Gas – water vapour in the air. – Solid – frozen ice caps for the Arctic and Antarctic. Water is constantly changing between these states in the water cycle. – Water cycle ensures that amount of water stays constant and that there is fresh water available.

Oxygen About 21% of Earth’s atmosphere consists of oxygen. Oxygen is essential for respiration. It is believed that the amount of oxygen has increased as life has become more complex. – Early simple life forms (types of bacteria – green blue algae) were the first to start producing oxygen.

Why Mars? After the Earth, Mars is the most habitable planet in our solar system due to several reasons: – Its soil contains water to extract – It isn’t too cold or too hot – There is enough sunlight to use solar panels – Gravity on Mars is 38% that of our Earth's, which is believed by many to be sufficient for the human body to adapt to – It has an atmosphere (albeit a thin one) that offers protection from cosmic and the Sun's radiation – The day/night rhythm is very similar to ours here on Earth: a Mars day is 24 hours, 39 minutes and 35 seconds The only other two celestial bodies in orbits near the Earth are our Moon and Venus. There are far fewer vital resources on the Moon, and a Moon day takes a month. It also does not have an atmosphere to form a barrier against radiation. Venus is a veritable purgatory. The average temperature is over 400 degrees, the barometric pressure is that of 900 meters underwater on Earth, and the cherry on top comes in the form of occasional bouts of acid rain. It also has nights that last for 120 days. Humans cannot live on Mars without the help of technology, but compared to Venus it's paradise! – See more at: Mars one See more at: Mars one