Gianluca Masi and F. Nocetini captured imagery of the irregularly-shaped space rock named 4179 Toutatis through the Virtual Telescope Project on December 8th, 2012. Its closest approach to Earth will be nearly 4.4 million miles away.
Thursday 13 December 2012
Wednesday 12 December 2012
Tuesday 27 November 2012
Thursday 22 November 2012
Upcoming Celestial Events: December 2012
December 3 - Jupiter at Opposition. The giant planet will be at its closest approach to Earth and its face will be fully illuminated by the Sun. This is the best time to view and photograph Jupiter and its moons.
December 13 - New Moon. The Moon will be directly between the Earth and the Sun and will not be visible from Earth. This phase occurs at 08:42 UTC.
December 13, 14 - Geminids Meteor Shower. Considered by many to be the best meteor shower in the heavens, the Geminids are known for producing up to 60 multicolored meteors per hour at their peak. The peak of the shower usually occurs around December 13 & 14, although some meteors should be visible from December 6 - 19. The radiant point for this shower will be in the constellation Gemini. This year the new moon will guarantee a dark sky for what should be an awesome show. Best viewing is usually to the east after midnight from a dark location.
December 21 - December Solstice. The December solstice occurs at 11:12 UTC. The South Pole of the earth will be tilted toward the Sun, which will have reached its southernmost position in the sky and will be directly over the Tropic of Capricorn at 23.44 degrees south latitude. This is the first day of winter (winter solstice) in the northern hemisphere and the first day of summer (summer solstice) in the southern hemisphere.
December 28 - Full Moon. The Moon will be directly opposite the Earth from the Sun and will be fully illuminated as seen from Earth. This phase occurs at 10:21 UTC.
via: seasky.org
Monday 12 November 2012
Black Hole
- What is a Black Hole?
A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.Because no light can get out, people can't see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars.
- How Big Are Black Holes?
Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or "stuff," in an object.
Another kind of black hole is called "stellar." Its mass can be up to 20 times more than the mass of the sun. There may be many, many stellar mass black holes in Earth's galaxy. Earth's galaxy is called the Milky Way.
The largest black holes are called "supermassive." These black holes have masses that are more than 1 million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center. The supermassive black hole at the center of the Milky Way galaxy is called Sagittarius A. It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths.
- How Do Black Holes Form?
Scientists think the smallest black holes formed when the universe began.
Stellar black holes are made when the center of a very big star falls in upon itself, or collapses. When this happens, it causes a supernova. A supernova is an exploding star that blasts part of the star into space.
Scientists think supermassive black holes were made at the same time as the galaxy they are in.
If Black Holes Are "Black," How Do Scientists Know They Are There?
A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. But scientists can see how the strong gravity affects the stars and gas around the black hole. Scientists can study stars to find out if they are flying around, or orbiting, a black hole.
When a black hole and a star are close together, high-energy light is made. This kind of light can not be seen with human eyes. Scientists use satellites and telescopes in space to see the high-energy light.
- Could a Black Hole Destroy Earth?
Black holes do not go around in space eating stars, moons and planets. Earth will not fall into a black hole because no black hole is close enough to the solar system for Earth to do that.
Even if a black hole the same mass as the sun were to take the place of the sun, Earth still would not fall in. The black hole would have the same gravity as the sun. Earth and the other planets would orbit the black hole as they orbit the sun now.
The sun will never turn into a black hole. The sun is not a big enough star to make a black hole.
- Some interesting fun facts about black holes:
1) Just how an an object (like a ball) loses energy when attempting to leave Earths gravitational field, light also loses energy. The catch is, unlike the ball, light doesn't slow down, so it must lose energy some other way. As a photon moves away from a strong gravitational field the wavelength undergoes a gravitational redshift (redshift is when the light wave gets longer and shifts to the "redder" side of the spectrum). If light were to be emitted from inside the event horizon of a black hole, its wavelength would get infinitely long and the photon would vanish. This is one of the reasons nothing, even light, can escape from inside a black hole.
2) The very center of a black hole is called a singularity. At this singularity, spacetime has an infinite curvature and the laws of physics break down. Because the singularity is within the Schwarzschild radius it can never be observed. Physicists have theorized the existence of a naked singularity, which is a singularity without the event horizon (meaning it could be observed); so far, no one has observed one.
3) Since the escape velocity inside a black hole is greater than the speed of light, it is probable we will never know what happens inside the event horizon since information cannot be communicated across the Schwarzschild radius.
4) If the sun were replaced with a solar mass black hole (a black hole with the same mass as the sun), Earth would not be sucked in. In fact, Earth’s orbit would remain the same (with the lack of sunlight however, the inability for life to perform biological functions like photosynthesis would make things, shall we say… interesting).
5) Since black holes are not visible, scientists have to rely on other methods of detecting them. These include: accretion of matter, x-ray binaries, and gravitational lensing. All these methods rely on the gravitational interactions between visible matter and the invisible black hole.
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| Illustration of a Black Hole |
Via: nasa.gov
Sunday 11 November 2012
Upcoming Celestial Events: November
November 13 - New Moon. The Moon will be directly between the Earth and the Sun and will not be visible from Earth. This phase occurs at 22:08 UTC.
November 13 - Total Solar Eclipse. The path of totality will only be visible in parts of extreme northern Australia and the southern Pacific Ocean. A partial eclipse will be visible in most parts of eastern Australia and New Zealand.
(NASA Map and Eclipse Information)
November 17, 18 - Leonids Meteor Shower. The Leonids is one of the better meteor showers to observe, producing an average of 40 meteors per hour at their peak. The shower itself has a cyclic peak year every 33 years where hundreds of meteors can be seen each hour. The last of these occurred in 2001. The shower usually peaks on November 17 & 18, but you may see some meteors from November 13 - 20. The crescent moon will set early in the evening leaving dark skies for what should be an excellent show. Look for the shower radiating from the constellation Leo after midnight, and be sure to find a dark location for viewing.
November 27 - Conjunction of Venus and Saturn. These two bright planets will be within 1 degree of each other in the morning sky. Look to the east around sunrise.
November 28 - Full Moon. The Moon will be directly opposite the Earth from the Sun and will be fully illuminated as seen from Earth. This phase occurs at 14:46 UTC.
November 28 - Penumbral Lunar Eclipse. The eclipse will be visible throughout most of Europe, eastern Africa, Asia, Australia, the Pacific Ocean, and North America. (NASA Map and Eclipse Information)
via: seasky.org
November 13 - Total Solar Eclipse. The path of totality will only be visible in parts of extreme northern Australia and the southern Pacific Ocean. A partial eclipse will be visible in most parts of eastern Australia and New Zealand.
(NASA Map and Eclipse Information)
November 17, 18 - Leonids Meteor Shower. The Leonids is one of the better meteor showers to observe, producing an average of 40 meteors per hour at their peak. The shower itself has a cyclic peak year every 33 years where hundreds of meteors can be seen each hour. The last of these occurred in 2001. The shower usually peaks on November 17 & 18, but you may see some meteors from November 13 - 20. The crescent moon will set early in the evening leaving dark skies for what should be an excellent show. Look for the shower radiating from the constellation Leo after midnight, and be sure to find a dark location for viewing.
November 27 - Conjunction of Venus and Saturn. These two bright planets will be within 1 degree of each other in the morning sky. Look to the east around sunrise.
November 28 - Full Moon. The Moon will be directly opposite the Earth from the Sun and will be fully illuminated as seen from Earth. This phase occurs at 14:46 UTC.
November 28 - Penumbral Lunar Eclipse. The eclipse will be visible throughout most of Europe, eastern Africa, Asia, Australia, the Pacific Ocean, and North America. (NASA Map and Eclipse Information)
via: seasky.org
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