The more distant a galaxy the greater in direct

Info icon This preview shows pages 58–60. Sign up to view the full content.

View Full Document Right Arrow Icon
The more distant a galaxy, the greater, in direct proportion, its speed of _______________, as determined by the shift of its spectral lines to the longer (or red) wavelengths. Explanation: Recession. By the 1930's, M.L. Humason and Edwin Hubble had begun to photograph spectra of fainter galaxies and found that in general, the fainter and smaller a galaxy appeared, the higher was its redshift. This was then interpreted to mean that the more distant a galaxy, the higher its speed of recession--in other words, the faster it's moving away from us. This finding is known as the law of red shifts; it is often simply referred to as Hubble's Law. The currently most widely accepted theory for how the universe was formed is the ______ ________ theory. d Explanation: Big Bang. According to the Big Bang theory, the universe started around 12 to 14 billion years ago. There are other theories which have been espoused by big name scientists, but currently the Big Bang theory is the most commonly accepted and well-known explanation for how the universe came to be. In the Big Bang theory, everything originated from a single tiny, infinitely dense and hot and massive point known as a ______________. Explanation: Singularity. Inside of this singularity was contained all of the matter and energy of the universe, which means nothing (not even space) existed outside of it. This singularity then expanded into the universe as we know it today. Note that at the core of each black hole is also thought to exist a singularity. A singularity simply refers to a point of infinite density and infinitesimal (immeasurably small) volume. It is imagined that in a singularity, space and time would become infinitely distorted. There are three main ideas which are seen as supporting evidence by proponents of the Big Bang theory. The first is that according to Hubble's Law, the universe is ______________. Explanation: Expanding. As you recall, Hubble discovered that the light coming from almost all galaxies is redshifted (only about 100 galaxies have been recorded which are blueshifted), which he interpreted to mean that they are moving farther away and that the universe is expanding. This would suggest that at one time the universe was compacted.
Image of page 58

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The second big idea seen to support the Big Bang theory was the discovery of ________ radiation. Explanation: Cosmic Microwave Background (CMB) radiation. In 1948, three scientists Gamow, Alpher, and Herman predicted that based on the idea that the universe started out hot and dense, and proceeded to expand and cool, that there should be some kind of relic radiation left over spread out throughout the universe. In 1965, two radioastronomers, Penzias and Wilson, discovered what is cited today as one of the most compelling pieces of evidence of the Big Bang--microwave radiation with a temperature of about 2.7K that uniformly pervades the entire observable universe. This radiation, known as CMB radiation, is interpreted to be the left over heat from the Big Bang.
Image of page 59
Image of page 60
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern