The Universe Within Read Online Free Page A

and law student turned astronomer, deployed his enormous newMount Wilson telescope to find one of the stars made famous by Leavitt. This star was special. It wasn’t alone in the sky; it sat inside acloud of gas, known as the Andromeda Nebula. When Hubble applied Leavitt’s ruler to the star, he encountered a stunning fact: the star, in fact the whole nebula that contained it, was farther away from us than anything yet measured. The game changer came from the realization that this object was much more distant than any star in our own galaxy. This nebula was no cloud of gas; it was an entirely separate galaxy light-years from our own. With that observation, the Andromeda Nebula became theAndromeda Galaxy, and the world above our heads became vast and ancient almost beyond description.
    Hubble, using the largest telescope of the day, mapped everything he could see with Leavitt’s variable stars inside. The Andromeda and Milky WayGalaxies were only the tip of the iceberg. The heavens were filled with other galaxies composed of billions of stars. Many of the fuzzy patches of gas seen byobservers for a century or more were really star clusters that lie far beyond our own galaxy. In a scientificage when people were grappling with the age of Earth, then thought to be on the order of 10 million to 100 million years old, the age and size of the universe revealed our planet to be just a minuscule speck in a vast universe composed of innumerable galaxies. These insights emerged as people learned to look at the sky in a new way.
    Hubble applied another technique to measure objects in the sky. This one relied on an essential property of light. Light radiating from a source that is traveling toward us looks more blue than light traveling away, which looks more red. This color shift happens because light shares somefeatures with waves. Individual waves emanating from a source moving closer to you will look more compressed than ones moving away. In the world of color, more closely spaced waves are on the blue end of the spectrum, more separated ones on the red. If Leavitt’s technique was a ruler to measure distance in deep space, then the search for color shifts in light was a radar gun to measure speed.
    With this tool, Hubble found a regularity: stars emitred-shifted light. This could mean only one thing. The objects in the heavens are moving away from us, and the universe itself is expanding. Thisexpansion is not a pell-mell scatter; the heavens are scattering from a common center. Wind things back in time, and all the matter in the sky was at some distant time occupying a central point.
    Not everybody liked this new idea; in fact, some experts hated it. Rival theories for the origin of the universe abounded. A proponent for one of them poked fun at Hubble’s by giving it the moniker “big bang.” Lacking in Hubble’s theory, or in any other for that matter, was direct evidence in the form of a smoking gun.
    The major breakthrough was an incidental by-product of people’s need tocommunicate with one another. With technological innovations in wireless technology and expanding international commerce and collaboration in the late 1950s came a demand fortransmission ofradio, TV, and other signals across the oceans.NASA devised a specialsatellite, code-named Echo 1, for this purpose. Looking like a large shiny metal balloon, it was meant to bounce signals transmitted from one part of Earth to another. The problem with this system was that the signals returning to Earth were often far too weak to interpret.
    Working for AT&T’sBell Laboratories, at the time a utopia for scientists doing creative science,Arno Penzias andRobert Wilson were designing a radar dish to detect the extremely weak microwave signals reflected from NASA’sEcho 1 satellite. They spent a considerable amount of time, money, and expertise to develop a specialized radar dish for the task. Then, in 1962, NASA launchedTelstar, a satellite that doesn’t passively