ORIGENS (2)

ORIGENS com Neil deGrasse Tyson

Terá o universo sempre existido? Como é que se tornou num lugar que abriga vida? Como terá sido o nascimento do nosso planeta? Estamos sozinhos, ou existem mundos extraterrestres à espera de serem descobertos?

Veja algumas respostas assustadoras em "ORIGENS", um documentário pioneiro apresentado por Neil deGrasse Tyson, que levará os espectadores numa viagem pelo cosmos desde o princípio do tempo até aos confins do Universo, procurando pelas primeiras pistas de vida e os seus vestígios em outros mundos.

Documentário - ORIGENS: Como a vida começou - com NEIL DEGRASSE TYSON. Tempo aproximado de 50 minutos (em inglês).

Veja também a postagem: "ORIGENS - Livro" neste site.

MARS AND EARTH: SUNSETS

TWO WORLDS, ONE SUN

There’s an image going around of a blue sunset on Mars. Yes, it’s a real image, and yes, the colors are reasonably true to life. It was taken by the Curiosity rover in April. Given that sunsets on Earth are typically red, how does Mars get a blue sunset? It all has to do with the way light scatters in the atmospheres of Earth and Mars.

Earth and Mars: sunsets.

Earth has a relatively thick atmosphere, so most of the atmospheric scattering occurs when light strikes a molecule of air, known as Rayleigh scattering. Rayleigh scattering occurs when the object a photon scatters off (the air molecule) is much smaller than the wavelength of the photon. The closer the wavelength is to the size of the molecule, the more likely it is to scatter. This means that red wavelengths (which are the longer wavelengths of visible light) don’t scatter with air molecules much, while blue wavelengths (which are shorter) tend to scatter a lot. In fact blue light is almost 10 times more likely to scatter against air molecules than red light. This is why the sky appears blue, since so much of the blue light is scattered.

When the Sun is low in the sky, it’s light has to travel a long path through the atmosphere to reach you. As the light travels through the atmosphere some of the photons are scattered off the air molecules. When the photons scatter off air molecules, they scatter randomly in all directions, so usually when a photon scatters, it scatters away from your line of sight. Since blue photons scatter much more often than red ones, much of the blue light is scattered away. This leaves red photons to reach your eye. Hence the Sun looks red when low in the sky. When the Sun is overhead, the path it takes to reach you is much shorter, so only a bit of the blue light is scattered. So the Sun looks yellow.

A daytime Martian sky (left) vs a Martian sunset (right). Credit: NASA / JPL-Caltech / MSSS / Damia Bouic.

Mars has a much thinner atmosphere, so the amount of Rayleigh scattering is much less. But Mars also has a dry, dusty surface, and a weaker surface gravity, so the atmosphere of Mars is often filled with fine dust particles. These particles are more comparable in size to the wavelengths of visible light, so most of the light is scattered by Mie scattering. One of the main differences between Rayleigh and Mie scattering is that Rayleigh scattering tends to occur in all directions, but Mie scattering varies with scattering angle. What this means is that longer wavelengths (reds) tend to scatter more uniformly, while shorter wavelengths (blues) tend to scatter at slight angles. This means that blue light tends to be deflected less than red light. This means Mars can have a dusty red daytime sky, and a blue sunset.

Mie scattering does occur on Earth as well, but since Mie scattering is less efficient than Rayleigh scattering it’s never strong enough to give us a blue sunset. It can (rarely) produce a blue moon. The most widespread incidence of modern history occurred after the eruption of Krakatoa in 1883, which sent so much ash into the atmosphere it produced brilliantly red sunsets and visibly blue moons all across the globe for nearly two years. As a result, the phrase “once in a blue moon” came to mean a rare occurrence.

Earth and Mars: the Sun.

Original: One Universe at a Time.

RIDE THE SKY (Live at Sweden Rock 2015)

Ride the sky - Lucifer's Friend (live 2015)

Ride the sky - Live version at Sweden Rock 2015 [ATTENTION: PLAY AT 1.25 SPEED].

Ride the sky

Travelling this dark world, leaving light behind

Seeing things I shouldn't see

New eyes I got to find

Mars Venus and stars shaking their heads at me

No more todays - tonight I'll be riding the sky

          Hey world look out I'm coming

          Friends pass me by and you saw me humming

          Mars Venus and stars shaking their heads at me

          No more todays - tonight I'll be riding the sky

          Tonight ride the sky, tonight ride the sky

                    The smile on his face turn me to stone

                    The words that he spoke wouldn't leave me alone

                    Mars Venus and stars shaking their heads at me

                    No more todays tonight I'll be riding the sky

                    Tonight ride the sky, tonight ride the sky,

                    Tonight ride the sky

                    Tonight ride the sky...

Lucifer's Friend is a German hard rock band, formed in Hamburg in 1970 by guitarist Peter Hesslein, singer John Lawton, bassist Dieter Horns, keyboardist Peter Hecht, and drummer Joachim Reitenbach. The group was noted as early practitioners of heavy metal and progressive rock, they also incorporated elements of jazz and fusion into their music, especially in their fourth album Banquet of 1974. Furthermore heavy metal, the band has been cited, too, as one of the pioneers of doom metal, helping to define both genres due to their heavy sound and dark oriented lyrics of their acclaimed debut Lucifer's Friend of 1970.

Ride the sky - Original version 1970.

Ride the sky - Live version 70's.

Ride the sky - 1994 new studio version.

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MATEMÁTICA (GIF)

Para entender melhor a matemática de uma maneira diferente.

Teorema de Pitágoras

Conceito de Radiano (razão entre o comprimento de um arco e o seu raio)

Triângulo de Pascal

How to create an elipse - Como criar uma elipse

Ângulos exteriores de polígono

Seno e Cosseno (1)

Seno e Cosseno (2)

Seno e Cosseno (3)

Aplicação de Seno e Cosseno

Cosseno derivada do Seno

Pi (π = 3,14159)

Logaritmos

Matriz transposta

How to create a parabola - Como criar uma parábola

Tangente

Curva de largura constante para fazer furos quadrados

Dobra Miura

Triângulo de Sierpinsk

Transformando coordenadas cartesianas em coordenadas polares

Um hiperboloide composto por linhas retas (1)

Um hiperboloide composto por linhas retas (2)

Soma de Riemann é a área aproximada sob uma curva

Propriedades reflexivas da elipse

Phi (ϕ = 1,618)

Toro

Asteroide (1)

Asteroide (2)

Roda de Aristóteles

Cardioide

Deltoide catacáustico

Teorema de Fontené

Teorema Griffith

Evolução de espiral logarítmica

Círculos de McCay

FONTE: https://www.oficinadanet.com.br/post/14648-37-gifs-pra-aprender-matematica-parte-1

PLACAS TECTÔNICAS DA AUSTRÁLIA

O movimento das placas tectônicas da superfície da Terra fez a Austrália mudar de lugar. O país está sendo deslocado para o norte e sua posição nos mapas e GPSs terá de ser corrigida.

Movimentação das placas tectônicas da Austrália.

As placas tectônicas que estão sob a Austrália se movimentam com bastante velocidade, deslocando o país para o norte cerca de 6,85 centímetros a cada ano, com uma micro rotação em sentido horário. Essas movimentações acontecem com muita velocidade de acordo com os padrões geológicos.

Devido a essas movimentações as longitudes e latitudes da Austrália serão reconfiguradas.