If someone ever asks you for proves that Earth is round, you can use one or more of those proves:
Gravity explained - from Newton to Einstein
One of four fundamental forces of nature is gravity. It's weakest force of all and always is attractive. Gravtiation force is proportional to body masses and inversly proportional to the square distance between them. From a cosmological perspective, gravitation causes dispersed matter to coalesce, and coalesced matter to remain intact, thus accounting for the existence of planets, stars, galaxies and most of the macroscopic objects in the universe. It is responsible for keeping the Earth and the other planets in their orbits around the Sun; for keeping the Moon in its orbit around the Earth; for the formation of tides; for natural convection, by which fluid flow occurs under the influence of a density gradient and gravity; for heating the interiors of forming stars and planets to very high temperatures; and for various other phenomena observed on Earth and throughout the universe.
This clip is taken from the NOVA PBS series "THE ELEGANT UNIVERSE' and is used under the provisions of the Digital Millineum Copyright Act of 1998 (Title IV).
Brian Greene guides us through Newton's discovery of gravity to the explanation of it, through Einsteins Theory of Relativity.
Brian Greene is a theoretical physicist and one of the best-known string theorists. Since 1996 he has been a professor at Columbia University.
The Elegant Universe was adapted for a three hour program in three parts for television broadcast in late 2003 on the PBS series NOVA.
This clip is taken from the NOVA PBS series "THE ELEGANT UNIVERSE' and is used under the provisions of the Digital Millineum Copyright Act of 1998 (Title IV).
Brian Greene guides us through Newton's discovery of gravity to the explanation of it, through Einsteins Theory of Relativity.
Brian Greene is a theoretical physicist and one of the best-known string theorists. Since 1996 he has been a professor at Columbia University.
The Elegant Universe was adapted for a three hour program in three parts for television broadcast in late 2003 on the PBS series NOVA.
Ring Nebula explained
The RIng Nebula (Messier 57) is one of the most known objects on sky. It is a planetary nebula in the northern constellation of Lyra.
The NASA/ESA Hubble Space Telescope and Hubblecast bring you a new and detailed look at the famous Ring Nebula. The Ring's distinctive shape makes it a popular illustration for astronomy books. But new observations of the glowing gas shroud around an old, dying, Sun-like star reveal a new twist.
Hubble and several ground-based telescopes have combined to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula.
The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers. Previous observations by several telescopes had detected the gaseous material in the ring's central region. But the new view by Hubble's sharp-eyed Wide Field Camera 3 shows the nebula's structure in more detail. The ring appears to wrap around a blue, football-shaped structure. Each end of the structure protrudes out of opposite sides of the ring.
The nebula is tilted toward Earth so that astronomers see the ring face-on. In the Hubble image, the blue structure is the glow of helium. Radiation from the white dwarf star, the white dot in the center of the ring, is exciting the helium to glow. The white dwarf is the stellar remnant of a Sun-like star that has exhausted its hydrogen fuel and has shed its outer layers of gas to gravitationally collapse to a compact object.
The dark, irregular knots of dense gas embedded along the inner rim of the ring look like spokes in a bicycle wheel. These gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the doomed star. The knots are more resistant to erosion by the wave of ultraviolet light unleashed by the star. The Hubble images have allowed astronomers to match up the knots with the spikes of light around the bright, main ring, which are a shadow effect. Astronomers have found similar knots in other planetary nebulae.
All of this gas was expelled by the central star about 4,000 years ago. The original star was several times more massive than our Sun. After billions of years converting hydrogen to helium in its core, the star began to run out of fuel. It then ballooned in size, becoming a red giant. During this phase, the star shed its outer gaseous layers into space and began to collapse as fusion reactions began to die out. A gusher of ultraviolet light from the dying star energized the gas, making it glow.
The outer rings were formed when faster-moving gas slammed into slower-moving material. The nebula is expanding at more than 43,000 miles an hour, but the center is moving faster than the expansion of the main ring. The Ring Nebula will continue to expand for another 10,000 years, a short phase in the lifetime of the star. The nebula will become fainter and fainter until it merges with the interstellar medium.
Studying the Ring Nebula's fate will provide insight into the Sun's demise in another 6 billion years. The Sun is less massive than the Ring Nebula's progenitor star, so it will not have such an opulent ending.
Hubble Space Telescope
Hubble, iconic telescope that opened our eyes for miracles of Universe. Responsible for unlocking many mysteries of the final frontier, the most renowned telescope in the world is in danger of being lost forever. The Hubble Space Telescope has explored the creation of stars and planets, the glory of supernovas and the formation of super massive black holes, charted dark matter and changed forever our understanding of reality itself. Now, it's spiraling toward the Earth, and astronauts are embarking on a dangerous mission to fix it.
In Hubble's Amazing Universe, glimpse the far ends of the universe as seen through the amazing Hubble Space Telescope, and meet one of the astronauts risking everything to save it.
We bring you amazing documentary made on National Geographic Channel abuotu Hubble Telescope.
Are We Alone - Discovery channel
Are We Alone is the name of interesting serial on Discovery Channel. It helps us answer many questions from astronomy, astrophysics, cosmology,....
Roundest object on Earth
Do you know what is the roundest object in the world? It's a PERFECT sphere made of silicone, and it will be used to redefine a base unit of mass - one kilogram. In this video you can see a story about this roundest object and story about unit of mass...
A kilogram isn't what it used to be. Literally. The original name for it was the 'grave', proposed in 1793 but it fell victim to the French Revolution like its creator, Lavoisier. So begins the tale of the most unusual SI unit. The kilogram is the only base unit with a prefix in its name, and the only one still defined by a physical artifact, the international prototype kilogram or IPK.
But the problem with this definition has long been apparent. The IPK doesn't seem to maintain its mass compared to 40 similar cylinders minted at the same time. The goal is therefore to eliminate the kilogram's dependence on a physical object. Two main approaches are being considered to achieve this end: the Avogadro Project and the Watt Balance.
The Avogadro project aims to redefine Avogadro's constant (currently defined by the kilogram -- the number of atoms in 12 g of carbon-12) and reverse the relationship so that the kilogram is precisely specified by Avogadro's constant. This method required creating the most perfect sphere on Earth. It is made out of a single crystal of silicon 28 atoms. By carefully measuring the diameter, the volume can be precisely specified. Since the atom spacing of silicon is well known, the number of atoms in a sphere can be accurately calculated. This allows for a very precise determination of Avogadro's constant.
The Curvature of the Earth
There are many ways to prove that our Mother Earth is rounded. One of them is that humans (austornauts) saw it. We bring you beautifull compilation of videos made from International Space Station...
Watch this on the largest screen available. This 4k video features some of the most astonishingly beautiful images from the Gateway to Astronaut Photography based at NASA's Johnson Space Center.
Watch this on the largest screen available. This 4k video features some of the most astonishingly beautiful images from the Gateway to Astronaut Photography based at NASA's Johnson Space Center.
Wierd chemical reaction
This video shows incredible chemical reaction of Mercury(II) thiocyanate while it decomposite. Cause of decomposition is heat.
