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Space. M104b_peris2048.jpg (2048×1410) The Carl Sagan Portal. The Planetary Society. 0.10-bortle.jpg from NASA Astrobiology. NASA Spitzer Space Telescope. Interactive 3D model of Solar System Planets and Night Sky. The Scale of the Universe. Scale of Universe - Interactive Scale of the Universe Tool. Large-scale structure of the Universe‬‏ HubbleSite - Out of the ordinary...out of this world. Cell Size and Scale. Some cells are visible to the unaided eye The smallest objects that the unaided human eye can see are about 0.1 mm long.

Cell Size and Scale

That means that under the right conditions, you might be able to see an ameoba proteus, a human egg, and a paramecium without using magnification. A magnifying glass can help you to see them more clearly, but they will still look tiny. Smaller cells are easily visible under a light microscope. It's even possible to make out structures within the cell, such as the nucleus, mitochondria and chloroplasts. To see anything smaller than 500 nm, you will need an electron microscope. How can an X chromosome be nearly as big as the head of the sperm cell? No, this isn't a mistake. The X chromosome is shown here in a condensed state, as it would appear in a cell that's going through mitosis. A chromosome is made up of genetic material (one long piece of DNA) wrapped around structural support proteins (histones). Adenine The label on the nucleotide is not quite accurate.

Carbon. Alien Earths Online - Astronomy Picture of the Day. Discover the cosmos!

Astronomy Picture of the Day

Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2015 January 3 Apollo 17: A Stereo View from Lunar Orbit Image Credit: Gene Cernan, Apollo 17, NASA; Anaglyph by Patrick Vantuyne Explanation: Get out your red/blue glasses and check out this awesome stereo view of another world. The scene was recorded by Apollo 17 mission commander Eugene Cernan on December 11, 1972, one orbit before descending to land on the Moon. Tomorrow's picture: ringside Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)NASA Official: Phillip Newman Specific rights apply.NASA Web Privacy Policy and Important NoticesA service of:ASD at NASA / GSFC& Michigan Tech.

Watch the Program (full-screen) The Elegant Universe: Part 3 PBS Airdate: November 4, 2003 NARRATOR: Now, on NOVA, take a thrill ride into a world stranger than science fiction, where you play the game by breaking some rules, where a new view of the universe pushes you beyond the limits of your wildest imagination.

Watch the Program (full-screen)

This is the world of "string theory," a way of describing every force and all matter from an atom to earth, to the end of the galaxies—from the birth of time to its final tick, in a single theory, a "Theory of Everything. " Our guide to this brave new world is Brian Greene, the bestselling author and physicist. BRIAN GREENE (Columbia University): And no matter how many times I come here, I never seem to get used to it. NARRATOR: Can he help us solve the greatest puzzle of modern physics—that our understanding of the universe is based on two sets of laws that don't agree?

NARRATOR: Resolving that contradiction eluded even Einstein, who made it his final quest. S. BRIAN GREENE:The atmosphere was electric. Astronomy Magazine - Interactive Star Charts, Planets, Meteors, Comets, Telescopes. Gateway to the Universe of X-ray Astronomy! The Universe in Colour.