A coisa mais bonita que podemos experimentar é o mistério.
Ele é a fonte de toda arte e ciência verdadeiras. Aquele para quem essa emoção é estranha, incapaz de soltar a imaginação e quedar-se extasiado, é como se fosse um morto: seus olhos estão fechados. (...) Saber que aquilo que nos é impenetrável realmente existe, manifestando-se como a maior sabedoria e a beleza mais radiante que nossa pobre capacidade só pode apreender em suas formas mais primitivas – esse conhecimento, essa sensação, está no centro da verdadeira religiosidade.
Nesse sentido, e apenas nesse, pertenço às fileiras dos devotos.
A tremendous tornado whirling across the surface of the sun was captured by a NASA satellite recently -- an amazing wonder of the solar system that may be as big as the Earth itself.
The video was recorded by the Solar Dynamics Observatory (SDO), a sun-watching satellite that has transmitted a series of stunning photos of solar flares in recent months. The new video shows darker, cooler plasma shifting back and forth above the sun's surface over the span of nearly 30 hours stretching from Feb. 7 to Feb. 8. And the giant tornado may be as large as the Earth itself, with gusts of up to 300,000 mph, explained Terry Kucera, deputy SOHO project scientist and a solar physicist with NASA's Goddard Space Flight Center. "It's about 15,000 degrees Fahrenheit -- relatively cool," Kucera told FoxNews.com. After all, the sun's corona is a whopping 2 million degrees, she explained.
Such tornadoes (Kucera classed it a "solar prominence") have been known of for decades; the European Space Agency's SOHO spacecraft captured evidence of them as early as 1996, mainly near the Sun's north and south poles at the time. And though they resemble their cousins here on Earth, they're created entirely differently, Kucera said -- through magnetism, not pressure and temperature fluctuations. "Those motions you see, it's all just moving along the magnetic field somehow -- but we're still looking to understand what's happening with these things," Kucera said.
The storm was created by competing magnetic forces, which pull the charged magnetic particles on the sun back and forth, creating a spinning mass of plasma that tracks along strands of magnetic field lines, NASA explained. The spinning top of the tornado is mesmerizing, but Kucera noted the span of the prominence as well. The long, ribbon shapes could span hundreds of thousands of miles, she said. "In total length, this could be dozens of Earths -- quite large," she said. Such detailed, high-resolution recordings of the immense tornadoes was not possible until the launch of SDO. The satellite has several cameras on board that capture solar activity in different wavelengths and frequencies, all in the name of science. "Each wavelength of light tells us something different," she said.
This animation shows Venus, a planet very similar to Earth in mass and size, but with a crushing atmosphere, sulphuric acid clouds and surface temperatures in excess of 460ºC. Venus Express is helping scientists to understand how a planet with similar physical characteristics to Earth evolved in a way so fundamentally different.
Why did Earth thrive and our sister planet, Venus, died? From the fires of a sun's birth... twin planets emerged. Then their paths diverged. Nature draped one world in the greens and blues of life. While enveloping the other in acid clouds... high heat... and volcanic flows. Why did Venus take such a disastrous turn?
For as long as we have gazed upon the stars, they have offered few signs... that somewhere out there... are worlds as rich and diverse as our own. Recently, though, astronomers have found ways to see into the bright lights of nearby stars.
They've been discovering planets at a rapid clip... using observatories like NASA's Kepler space telescope... A French observatory known as Corot ... .And an array of ground-based instruments. The count is approaching 500... and rising. These alien worlds run the gamut... from great gas giants many times the size of our Jupiter... to rocky, charred remnants that burned when their parent star exploded.
Some have wild elliptical orbits... swinging far out into space... then diving into scorching stellar winds. Still others orbit so close to their parent stars that their surfaces are likely bathed in molten rock. Amid these hostile realms, a few bear tantalizing hints of water or ice... ingredients needed to nurture life as we know it. The race to find other Earths has raised anew the ancient question... whether, out in the folds of our galaxy, planets like our own are abundant... and life commonplace? Or whether Earth is a rare Garden of Eden in a barren universe?
With so little direct evidence of these other worlds to go on, we have only the stories of planets within our own solar system to gauge the chances of finding another Earth. Consider, for example, a world that has long had the look and feel of a life-bearing planet. Except for the moon, there's no brighter light in our night skies than the planet Venus... known as both the morning and the evening star.
The ancient Romans named it for their goddess of beauty and love. In time, the master painters transformed this classical symbol into an erotic figure. It was a scientist, Galileo Galilei, who demystified planet Venus... charting its phases as it moved around the sun, drawing it into the ranks of the other planets.
With a similar size and weight, Venus became known as Earth's sister planet. But how Earth-like is it? The Russian scientist Mikkhail Lomonosov caught a tantalizing hint in 1761. As Venus passed in front of the Sun, he witnessed a hair thin luminescence on its edge.
Venus, he found, has an atmosphere. Later observations revealed a thick layer of clouds. Astronomers imagined they were made of water vapor, like those on Earth. Did they obscure stormy, wet conditions below? And did anyone, or anything, live there?
NASA sent Mariner 2 to Venus in 1962... in the first-ever close planetary encounter. Its instruments showed that Venus is nothing at all like Earth. Rather, it's extremely hot, with an atmosphere made up mostly of carbon dioxide.
The data showed that Venus rotates very slowly... only once every 243 Earth days... and it goes in the opposite direction. American and Soviet scientists found out just how strange Venus is when they sent a series of landers down to take direct readings.
Surface temperatures are almost 900 degrees Fahrenheit, hot enough to melt lead, with the air pressure 90 times higher than at sea level on Earth. The air is so thick that it's not a gas, but a "supercritical fluid." Liquid CO2. On our planet, the only naturally occurring source is in the high-temperature, high-pressure environments of undersea volcanoes. It comes in handy for extracting caffeine from coffee beans... or drycleaning our clothes.
You just wouldn't want to have to breathe it. The Soviet Venera landers sent back pictures showing that Venus is a vast garden of rock, with no water in sight. In fact, if you were to smooth out the surface of Venus, all the water in the atmosphere would be just 3 centimeters deep. Compare that to Earth... where the oceans would form a layer 3 kilometers deep.
If you could land on Venus, you'd be treated to tranquil vistas and sunset skies, painted in orange hues. The winds are light, only a few miles per hour... but the air is so thick that a breeze would knock you over. Look up and you'd see fast-moving clouds... streaking around the planet at 300 kilometers per hour. These clouds form a dense high-altitude layer, from 45 to 66 kilometers above the surface.
The clouds are so dense and reflective that Venus absorbs much less solar energy than Earth, even though it's 30% closer to the Sun.
The first Vega, flight VV01, lifted off from Europe's Spaceport in Kourou, French Guiana on 13 February 2012, on its way to carry nine satellites into orbit. This maiden voyage will add a new capability to Europe's fleet of launch systems. Vega's first payload consists of two Italian satellites: ASI's LARES laser relativity satellite and the University of Bologna's ALMASat-1. Flight VV01 will also carry seven picosatellites provided by European universities: e-St@r (Italy), Goliat (Romania), MaSat-1 (Hungary), PW-Sat (Poland), Robusta (France), UniCubeSat GG (Italy) and Xatcobeo (Spain). The mission is intended to qualify the overall Vega system, including the vehicle itself, its launch infrastructure and its operation; from the launch campaign to the payload separation and the safe disposal of the upper stage.
Pois é, chegámos aos 400.000 visitantes. Antes do final do ano lectivo devemos atingir o meio milhão, ou até mesmo mais, quase de certeza.
Obrigado a todos. Esperamos continuar a contar com a vossa visita. Aproveito a ocasião para renovar a nossa disponibilidade para aceitar as vossas colaborações. Querem publicar trabalhos? Têm fichas e outros materiais de apoio que gostaria de publicar para os vossos alunos mas não tem tempo ou paciência? Contactem-nos. Podemos até arranjar um espacinho só vosso no site, que no fundo é de todos. E melhor de tudo, agora em época de restrições orçamentais e afins, É TOTAL E VERDADEIRAMENTE GRÁTIS....
O Professor Nuno Botelho, Algarvio de gema, tem um excelente site com magníficos conteúdos, muito interessantes e seguramente úteis para quem quer aprender a física e a química. Recomendada a visita:
