Thursday, June 9, 2011

Solar Prominence

Solar prominence are purple jets of heated matter that during the full eclipse can be observed by the edge of the Sun. Prominence are of the different shapes, sizes and behaviors. Spiculae can be considered as prominence, however tiny. The temperature of the prominence is lower than of the environment and is about 10 000 K, but the density of gas in them is higher and therefore they are brighter.

The survival of these phenomena in rarer corona is only possible if the pressure of the gas of the prominence is equal to the pressure of the prominence of the surrounding corona. Gas pressure is proportional to its density and temperature, therefore, how many times a higher density of gas of prominence is, so many times his temperature is lower than the temperature of surrounding corona.

Considering the prominence density is 100 times greater than in the corona, substance must be in it for as many times in a lower temperature. Magnetic field has a crucial influence on the motion of particles inside the prominence, therefore, they can be considered as materialization of magnetic field above the active area.


The average prominence last about three suns trades, but the ones that have lasted years and over were seen. They occur most frequently in the form of quiet prominence, they are fixed and can be seen in all parts of the Sun. They have a length of about 200 000 km and in extreme cases may extend up to 1.9 million km. They rise to a height of about 50 000 km, while their width does not exceed 6000 km. They consist of flow whose diameters are about 1000 km. Temperature of quiet prominence usually amounts to about 15 000 K. They can be likened to a bridge or viaduct. The lower ends of the prominence have a foothold in the area between supergranules, they moved at various heliographic latitudes and change direction.

In addition to quiet there are active prominences. Active prominence develop very rapidly (from ten minutes to several hours), and appear at all heliographic latitudes. The best they can be seen when they take the form of loop. Then you can detect the movement of matter in the prominence. It can be seen how the gas interflows from down the sides of loops or how arises from the chromosphere on one side, moves along the loop and immersed in the chromosphere on the other side. Gas flows along the magnetic field lines at speeds of several hundred kilometers per second. The average gas temperature in the active prominence is approximately 25 000 kelvins.

In the areas of sunspots appears so called eruptive prominences. Unlike previous prominences, the prominence of this type spreads to a very great height, even more than a million kilometers. They most frequently occurring in the form of the arch that is rapidly increasing, and after a breaking of arch material falls back into the chromosphere. Another group are prominences of sunspots. The name itself says that they are always associated with groups of spots. Their forms follow the lines of forces of strong magnetic fields and when they are on the edge of the Sun, they are seen in a loop.

Wednesday, June 8, 2011

Dwarf Planet Eris

Eris, 136 199 Eris, is the largest known dwarf planet and for now the largest body found in Kuiper Belt. Although his discoverers initially declared him as the tenth planet in the solar system, the discovery of this object is, in addition to the long debate over whether Pluto is a planet at all, encouraged to redefine the concept of the planet in August 2006th by the International Astronomical Union, which along with Pluto Eris was classified into the category of dwarf planets. Eris distance from the Sun is 97 AU and has a diameter between 2400 and 3000 km, and mass about 1.66x1022 kg (27% larger than Pluto). The news of the discovery was announced on 29 July 2005. It is believed that this body is made of stone and ice.

His route is very elongated. At a time when is closest to the Sun it is inside Pluto's orbit, and when is the farthest, it is almost three times further than Pluto. Object 2003 UB313 named Eris go around the sun every 560 Earth years. Unlike the other planets whose paths lie almost in the plane of ecliptic, the path of "tenth" planet is tilted 45 degrees in relation to that plane. In October 2005th was discovered that he has a small companion named Dysnomia.

Shortly after the discover of this planet among astronomers began a new debate whether these objects are new planets or just one of them, or maybe none? Moreover, many people became clear that this discovery did not get the tenth planet, but we lost the ninth, because Pluto because of its elongated and inclined tracks and modest-sized is not planet.

Monday, June 6, 2011

Weightlessness

Weightlessness is a consequence of the equality of centripetal and centrifugal forces. During the levitation bodies lose its weight, but not the mass and inertia. This type of levitation is a functional and absolutely economical and at the very large distances of celestial bodies in relation to that which occur. It is necessary for the maintenance of artificial satellites in their orbits.

To maintain the real levitation requires no energy. Some satellite or celestial body can mediate between in relation to another heavenly body, many billions of years, and did not consume any energy. An illustrative example for this are geostationary satellites that hover motionless above a point on the equator, absolutely not wasting any energy. Energy must be spent only to achieve the speed of levitation and uplift above the atmosphere, ie the gas layer of those heavenly bodies that have it. Because of its peculiarities, this aspect of the real levitation is an extremely cost-effective means of satisfying some of the vital needs of humankind, but it is harmful to human health.

Crew  must prepare to live and work in a weightless state, so trainings are required. American astronauts trainees weightlessness first experience in a large transport aircraft KC135. This aircraft first climbs to a great height, and then sharply daffodils carefully calculating the curved path. Thus, the plane actually comes into a state of free fall, so passengers do not lose weight. Then the passengers by float in plane not feeling any more weight and trying to perform certain actions to see whether it would work well in space.

Some aspects of weightlessness trainees can experience working under water. They install equipment and perform repairs hovering underwater in space suits. Buoyancy as it creates water reverses the action of gravity. But stay under water is not equal in all to floating in space, because that can act on astronauts body in a very strange way.

The first few days in orbit most astronauts suffer various negative consequences, together called space disease. It lasts until the body adapts to new conditions, but even when the astronauts cease to feel bad, weightlessness can still harm the body because it causes loss of calcium from the bones and they become so fragile.

Sunday, June 5, 2011

What Is Solstice

What is solstice? Solstice is the moment at which the Sun, in the apparent motion around the Earth, reached the highest positive or negative slope, and then a day in which it occurs. Summer Solstice (the Earth's northern hemisphere) has been traditionally on 21st June, but around 22nd June the Sun reaches declination of +23°27', and then the day is the longest (about 16 hours) and night the shortest.

Winter solstice (Northern Hemisphere) , has been traditional on 21st December but around 22nd December declination of the sun reaches -23°27', when the day is the shortest (about 8 hours). The symbolism of the solstice determines its dual nature: summer solstice begins the summer, but the downward phase of the annual cycle, while with the winter solstice begins winter, but the upward phase, and is associated with winter and Christmas celebrations and all that re-birth, while associated with a summer feast of the Sun (even when he compares Christ with the sun and when it is celebrated as lord of the time).

Astronomical solstice is the moment when the sun reaches its greatest angular distance in relation to the equator. Solstice may be winter or summer. Even though their dates are usually cited as the 21st December and 21st June, the actual moment of solstice in the Gregorian calendar can be a day later or earlier.

Solstice is one of two events during the year when the Sun, seen from Earth, is the farthest on north or south in relation to the equator. The summer solstice occurs around June 21st, Winter Solstice occurs around December 21st. In the northern hemisphere, summer and winter officially begins on the day of summer and winter solstices.

Friday, June 3, 2011

What Is Equinox

Equinox is the phenomena in astronomy when the Earth's axis is perpendicular to the plane in which the Earth moves around the sun, and in the broader sense, dates and events that mark the beginning of spring (around 21 March) and autumn (around 23 September). Points on the celestial sphere where the ecliptic intersects the celestial equator is called the equinox point. The sun in its apparent motion along the ecliptic passes through the vernal point at the moment of the vernal equinox and the autumnal point in time of autumn equinox.

To date of equinox directions of sunrise and sunset are closest to the exact directions of east and west, and in the time of equinox sun's rays illuminate the earth's equator at a right angle. Duration of day and night is approximately 12 hours, but due to the effects of the atmosphere is not exactly the same. Since 2008th to 2101th, the vernal equinox falls on 19th or 20th March.

Equinox is one of two moments during the year when the sun is directly over Earth's equator. In the spring in the Northern Hemisphere, the vernal equinox occurs around March 21st, in the fall equinox occurs around September 21st (though the exact date varies slightly from year to year). During equinox, the length of day and night are equal all over the world. In Europe, spring and autumn officially begin at the vernal and autumnal equinoxes.

Name equinox comes from Latin and contains two words: aequus (equal) and nox (night) - because then, night and day are equally long.