Now we are not satisfied with the solar system and trying to explore outer solar system and earth like planets and other galaxies.
December 24, 2013
Space Travel
December 21, 2013
The Milky Way - Solar Systems - Nebula - Blackholes - Pulsars
The Milky Way is the galaxy that contains the Solar System.This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky. The term "Milky Way" is a translation of the Latin for "milky road", Via Lactea, in turn derived from the Greek kyklos galaktikos or "milky circle", "milk" also being the root for the Greek word for galaxy, (galaxias).
The galaxy has this appearance because of the Earth's position within the galactic plane around two thirds of the way out from the center, on the inner edge of the Orionâ€"Cygnus Arm, with the majority of the galaxy being seen edge on. The concept of this faint band of light being made up of stars was proven in 1610 when Galileo Galilei used his telescope to resolve it into individual stars. In the 1920s observations by astronomer Edwin Hubble showed that the Milky Way was just one of around 200 billion galaxies in the observable universe.
The Milky Way is a barred spiral galaxy 100,000-120,000 light-years in diameter containing 200â€"400 billion stars. The galaxy is estimated to contain 50 billion planets, 500 million of which could be located in the habitable zone of their parent star. Depending on its structure the entire galaxy has a rotational rate of 1 per 15 to 50 million years. The galaxy is also moving at a rate of 552 to 630 km per second depending on the relative frame of reference. It is estimated to be about 13.2 billion years old, nearly as old as the Universe. The Milky Way is part of the Local Group of galaxies.
The Milky Way is a barred spiral galaxy 100,000-120,000 light-years in diameter containing 200â€"400 billion stars. The galaxy is estimated to contain 50 billion planets, 500 million of which could be located in the habitable zone of their parent star. Depending on its structure the entire galaxy has a rotational rate of 1 per 15 to 50 million years. The galaxy is also moving at a rate of 552 to 630 km per second depending on the relative frame of reference. It is estimated to be about 13.2 billion years old, nearly as old as the Universe. The Milky Way is part of the Local Group of galaxies.
All the stars that can be seen in the night sky are part of the Milky Way galaxy, but for the purposes of the astronomical activity of observing the celestial sphere the term "Milky Way" is limited to the hazy band of white light arching around the entire night sky.The light originates from un-resolved stars and other material that lie within the galactic plane. Dark regions within the band, such as the Great Rift and the Coalsack, correspond to areas where light from distant stars is blocked by dark nebulae.
The Milky Way has a relatively low surface brightness with an apparent magnitude of around +4.5 to +5.[citation needed] Its visibility is greatly affected by how bright the night sky is (limiting magnitude) due to light pollution, stray light from the moon, etc. It becomes visible at limiting magnitudes of +5.1 or higher, showing a great deal of detail above +6.1.[15] This makes the Milky Way difficult to see from any urban or suburban location due to light pollution, but very prominent when viewed from a rural area.
The center of the galaxy lies in the direction of Sagittarius, and it is here that the Milky Way looks brightest. From Sagittarius, the hazy band of white light appears to pass westward through the constellations of Scorpius, Ara, Norma, Triangulum Australe, Circinus, Centaurus, Musca, Crux, Carina, Vela, Puppis, Canis Major, Monoceros, Orion and Gemini, Taurus, Auriga, Perseus, Andromeda, Cassiopeia, Cepheus and Lacerta, Cygnus, Vulpecula, Sagitta, Aquila, Ophiuchus, Scutum, and back to Sagittarius. The fact that the band divides the night sky into two roughly equal hemispheres indicates that the Solar System lies close to the galactic plane.
The galactic plane is inclined by about 60 degrees to the ecliptic (the plane of the Earth's orbit). Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth's equatorial plane and the plane of the ecliptic relative to the galactic plane. The north galactic pole is situated at right ascension 12h 49m, declination +27.4° (B1950) near beta Comae Berenices, and the south galactic pole is near alpha Sculptoris.
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Nasa Exploring Outer Solar System - New Exoplanets Founded
The Kepler mission is composed of the Kepler spacecraft equipped with the Kepler telescope and its mission is to find out Earth-like planets within just the Milky Way. The task is in movement for a couple of decades and has previously unveiled astonishing discoveries pertaining to the existence of habitable planets.
One particular of its most up-to-date discoveries, Kepler 22b, was unveiled Monday early morning, depicting the initial verified exoplanet that is orbiting a star very similar to our Sunshine (Kepler 22). The star is a bit smaller and colder than our star, but this only led to some transformed variables pertaining to the habitable zone all around it.
The new uncovered planet is explained to be two.4 instances more substantial than the Earth, with unfamiliar composition still. It could be rocky, liquid or gaseous in composition, but added calculations will consider area in 2012, when the world will be visible from the floor telescopes (these kinds of as Keck Observatory). The scientist declared that the planet orbits around its star in 290 and its orbit is fairly comparable to the one Earth has about our Sun. Calculations up to this level suggest that the temperature is also related to ours, estimating all-around 72 degrees F on the surface area.
The new software improvements produced to the telescope boosted the discoveries of possible Earth-like planets, reaching a complete of 2326. fifty five of people are greater than Jupiter, 203 have the size of Jupiter, 1181 look related toNeptunein size, 680 are super Earth in dimension and 207 are equivalent to our home planet.
It seems that the Kepler mission is on its way to even even larger, much more interesting discoveries in the in the vicinity of long term. At a person point it is probable to finally locate Earth's twin, or maybe even much more planets that can sustain existence, escalating SETI's likelihood of discovering intelligent daily life amid the stars of our galaxy. Right after that, new troubles will emerge in attempting a transport or developing communications, provided that all people planets are several light-several years absent, outdoors our latest get to.
One particular of its most up-to-date discoveries, Kepler 22b, was unveiled Monday early morning, depicting the initial verified exoplanet that is orbiting a star very similar to our Sunshine (Kepler 22). The star is a bit smaller and colder than our star, but this only led to some transformed variables pertaining to the habitable zone all around it.
The new uncovered planet is explained to be two.4 instances more substantial than the Earth, with unfamiliar composition still. It could be rocky, liquid or gaseous in composition, but added calculations will consider area in 2012, when the world will be visible from the floor telescopes (these kinds of as Keck Observatory). The scientist declared that the planet orbits around its star in 290 and its orbit is fairly comparable to the one Earth has about our Sun. Calculations up to this level suggest that the temperature is also related to ours, estimating all-around 72 degrees F on the surface area.
The new software improvements produced to the telescope boosted the discoveries of possible Earth-like planets, reaching a complete of 2326. fifty five of people are greater than Jupiter, 203 have the size of Jupiter, 1181 look related toNeptunein size, 680 are super Earth in dimension and 207 are equivalent to our home planet.
It seems that the Kepler mission is on its way to even even larger, much more interesting discoveries in the in the vicinity of long term. At a person point it is probable to finally locate Earth's twin, or maybe even much more planets that can sustain existence, escalating SETI's likelihood of discovering intelligent daily life amid the stars of our galaxy. Right after that, new troubles will emerge in attempting a transport or developing communications, provided that all people planets are several light-several years absent, outdoors our latest get to.
Members of the Solar System - Asteroids
The moon isn't the only hunk of space rock that has been travelling around the sun with the Earth for ages.
Canadian scientists have discovered that the Earth is also accompanied by a "Trojan" companion — an asteroid that travels a constant distance ahead of it at all times, sharing nearly the same orbit around the sun.
Similar objects have been found travelling with other planets in our solar system, including Mars, Jupiter and Neptune.
"In a way, these are sort of like secondary moons," said Martin Connors, the Alberta scientist who led the discovery published in Thursday's issue of Nature.
Like the moon, the asteroid known as 2010 TK7 is under the control of Earth's gravity and has been orbiting stably with the Earth for at least 10,000 years. However, Trojans are not satellites — unlike the moon, the Trojan asteroid does not orbit the Earth. Viewed from the Earth, the asteroid sits 60 degrees from the sun.
"You would think that the gravity of the planet would just like to pull the asteroid in," said Connors. "But when it does do that, it moves closer to the sun, and then the sun's gravity makes it go faster, and it pulls away from the planet again."
Gravity balancing act
Along the Earth's orbit, it is only when an object such as the asteroid sits at one of two Trojan points at a 60-degree angle from the Earth that the Earth's and the sun's gravity balance each other off, allowing the object to remain nearly stationary relative to the Earth.
2010 TK7 is about 300 metres across, making it rather large compared to other nearby asteroids. According to NASA, it is now about 80 million kilometres from Earth. By comparison, the moon is on average 384,000 km away.
Connors, who holds a Canada Research Chair in space science at Athabasca University, has been searching the skies for nearby Trojans for about 15 years.
It isn't easy because the area being searched is 60 degrees, or very close to the sun when viewed from Earth. That means the objects are only visible for a short time just before sunrise or just after sunset.
Connors combed through data collected by researchers at the University of California in Los Angeles from NASA's WISE (wide-field infrared survey explorer) telescope. It orbits the Earth and detects asteroids by scanning for the infrared radiation they give off after warming up in the sun. That radiation doesn't make it through the atmosphere, so it is invisible from Earth.
After finding two asteroids that looked like they could be Trojans, Connors sent the data to Paul Wiegert at the University of Western Ontario, who used computer modelling to see how similar objects should behave. That made it clear that the researchers would need more observations of the asteroid to confirm it was a Trojan.
They called upon Christian Veillet, executive director of the Canada-France-Hawaii Telescope in Kamuela, Hawaii, to use the telescope to scrutinize the asteroid's orbit for six days this past April. The observations confirmed that the asteroid is a Trojan.
Connors said the discovery of one Trojan orbiting with the Earth means there are likely others. Such nearby asteroids wouldn't require much energy to visit with a space probe, since they are so close and have a similar orbit to earth, he said. However, 2010 TK7 itself isn't a good candidate for such a visit because its orbit is tilted relative to the Earth's.
Trojan asteroids are of interest to scientists because they may hold material leftover from the formation of the solar system, Connors said. While meteorites also contain such material, they typically have wandered long distances and scientists can never be quite sure where they came from. Trojan asteroids likely have remained close to the Earth for a long time, and the material they contain is more likely to originate near the Earth.
Canadian scientists have discovered that the Earth is also accompanied by a "Trojan" companion — an asteroid that travels a constant distance ahead of it at all times, sharing nearly the same orbit around the sun.
Similar objects have been found travelling with other planets in our solar system, including Mars, Jupiter and Neptune.
"In a way, these are sort of like secondary moons," said Martin Connors, the Alberta scientist who led the discovery published in Thursday's issue of Nature.
Like the moon, the asteroid known as 2010 TK7 is under the control of Earth's gravity and has been orbiting stably with the Earth for at least 10,000 years. However, Trojans are not satellites — unlike the moon, the Trojan asteroid does not orbit the Earth. Viewed from the Earth, the asteroid sits 60 degrees from the sun.
"You would think that the gravity of the planet would just like to pull the asteroid in," said Connors. "But when it does do that, it moves closer to the sun, and then the sun's gravity makes it go faster, and it pulls away from the planet again."
Gravity balancing act
Along the Earth's orbit, it is only when an object such as the asteroid sits at one of two Trojan points at a 60-degree angle from the Earth that the Earth's and the sun's gravity balance each other off, allowing the object to remain nearly stationary relative to the Earth.
2010 TK7 is about 300 metres across, making it rather large compared to other nearby asteroids. According to NASA, it is now about 80 million kilometres from Earth. By comparison, the moon is on average 384,000 km away.
Connors, who holds a Canada Research Chair in space science at Athabasca University, has been searching the skies for nearby Trojans for about 15 years.
It isn't easy because the area being searched is 60 degrees, or very close to the sun when viewed from Earth. That means the objects are only visible for a short time just before sunrise or just after sunset.
Connors combed through data collected by researchers at the University of California in Los Angeles from NASA's WISE (wide-field infrared survey explorer) telescope. It orbits the Earth and detects asteroids by scanning for the infrared radiation they give off after warming up in the sun. That radiation doesn't make it through the atmosphere, so it is invisible from Earth.
After finding two asteroids that looked like they could be Trojans, Connors sent the data to Paul Wiegert at the University of Western Ontario, who used computer modelling to see how similar objects should behave. That made it clear that the researchers would need more observations of the asteroid to confirm it was a Trojan.
They called upon Christian Veillet, executive director of the Canada-France-Hawaii Telescope in Kamuela, Hawaii, to use the telescope to scrutinize the asteroid's orbit for six days this past April. The observations confirmed that the asteroid is a Trojan.
Connors said the discovery of one Trojan orbiting with the Earth means there are likely others. Such nearby asteroids wouldn't require much energy to visit with a space probe, since they are so close and have a similar orbit to earth, he said. However, 2010 TK7 itself isn't a good candidate for such a visit because its orbit is tilted relative to the Earth's.
Trojan asteroids are of interest to scientists because they may hold material leftover from the formation of the solar system, Connors said. While meteorites also contain such material, they typically have wandered long distances and scientists can never be quite sure where they came from. Trojan asteroids likely have remained close to the Earth for a long time, and the material they contain is more likely to originate near the Earth.
Source: Earth has asteroid companion
December 17, 2013
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