Evidence for the Big Bang

planck-attnotated-580x372The Big Bang Theory has been the dominant cosmological model for over half a century. According to the theory, the universe was created approximately 14 billion years ago from an extremely hot, dense state and then began expanding rapidly. After the initial expansion, the Universe cooled and began to form various subatomic particles and basic elements. Giant clouds of these primordial elements later coalesced through gravity to form stars, galaxies, and eventually planets.

And while it has its detractors, most of whom subscribe to the alternate Steady State Theory – which claims that new matter is continuously created as the universe expands – it has come to represent the scientific consensus as to how the universe came to be. And as usual, my ol’ pal and mentor in all things digital, Fraser Cain, recently released a video with the help of Universe Today discussing the particulars of it.

big_bangAddressing the particulars of the Big Bang Theory, Cain lists the many contributions made over the past century that has led this so-called theory to become the scientific consensus has come to exist. They are, in a nutshell:

  1. Cosmic Expanion: In 1912, astronomer Vesto Slipher calculated the speed and distance of “spiral nebulae” (galaxies) by measuring the light coming from them. He determined most were moving away. In 1924, Edwin Hubble determined that these galaxies were outside the Milky Way. He postulates that the motion of galaxies away from our own indicates a common point of origin.
  2. Abundance of Elements: Immediately after the big bang, only hydrogen existed and compressed into a tiny area of space under incredible heat and pressure. Like a star, this turned hydrogen into helium and other basic elements. Looking out into the universe (and hence back in time) scientists have found that great distances, the ratios of hydrogen to basic elements is consistent with what is found in star’s interiors.
  3. Cosmic Microwave Background (CMB) Radiation: In the 1960’s, using a radiotelescope, Arno Penzias and Robert Wilson discovered a background radio emission coming from every direction in the sky, day or night. This was consistent with the Big Bang Theory, which predicted that after the Big Bang, there would have been a release of radiation which then expanded billions of light years in all directions and cooled to the point that it shifted to invisible, microwave radiation.
  4. Large Scale Structure: The formation of galaxies and the large-scale structure of the cosmos are very similar. This is consistent with belief that after the initial Big Bang, the matter created would have cooled and began to coalesce into large collections, which is what galaxies, local galactic groups, and super-clusters are.

These are the four pillars of the Big Bang Theory, but they are no means the only points in its favor. In addition, there are numerous observational clues, such as how we have yet to observe a stars in the universe older than 13 billion years old, and fluctuations in the CMB that indicate a lack of uniformity. On top of that, there is the ongoing research into the existence of Dark Matter and Dark Energy, which are sure to bear fruit in the near future if all goes well.

big_bang1In short, scientists have a pretty good idea of how the universe came to be and the evidence all seems to confirm it. And some mysteries remain, we can be relatively confident that ongoing experimentation and research will come up with new and creative ways to shed light on the final unknowns. Little reason then why the Big Bang Theory enjoys such widespread support, much like Evolution, Gravity, and General Relativity.

Be sure to check out the full video, and subscribe to Universe Today for additional informative videos, podcasts, and articles. As someone who used to write for them, I can tell you that it’s a pretty good time, and very enlightening!

Powered by the Sun: New Film Increases Solar Efficiency

sun_magneticfieldWith every passing year, solar power is getting cheaper and more efficient. And with every development that brings costs down and increases electrical yields, the day that it comes to replace fossil fuels and coal as the primary means of meeting our power needs gets that much closer. And with this latest development, this changeover may be coming sooner than expected.

It comes from North Carolina State University where researchers have developed a new system for strengthening the connections between stacked solar cells which could allow cells to operate at concentrations of up to 70,000 suns while minimizing wasted energy. This is especially good news seeing as how stacked cells are already an improvement over conventional solar cells.solar_panelStacked solar cells are made up of several cells that are placed one on top of the other, an arrangement that allows up to 45 percent of the absorbed solar energy to be converted into electricity. This is a significant improvement over single-junction solar cells which have a theoretical maximum conversion rate of 33.7 percent, and is made possible by the fact a stack formation prevents heat from being lost between panels.

The team at NCSU discovered that by inserting a very thin film layer of gallium arsenide into the connecting junction of stacked cells, they can eliminate energy loss ever further. The idea was inspired by the fact that cells typically start to break down at the connection junctions once they reach concentrations of 700 suns. With the addition of gallium arsenide in these spots, the connections become stronger, and all without sacrificing absorption.

solar_cell1Dr. Salah Bedair, a professor of electrical engineering at NCSU and senior author of the paper on this research:

Now we have created a connecting junction that loses almost no voltage, even when the stacked solar cell is exposed to 70,000 suns of solar energy. And that is more than sufficient for practical purposes, since concentrating lenses are unlikely to create more than 4,000 or 5,000 suns worth of energy.

At the moment, this technology is geared towards large scale solar power operations. Stacked cells are usually used in conjunction with optical concentration devices, such as Fresnel lenses, and mounted on a dual-axis solar trackers that keep the cell facing the Sun’s rays during daylight. So basically, we’re not likely to be seeing this technology available for local use. But it would be surprising if domestic consumers weren’t likely to benefit from it all the same.

solar_cell_galliumAs Dr. Bedair explained, the adoption of the technology will mean lower costs for the energy industry, and smaller arrays which will mean less land that needs to be set aside for use:

This [system] should reduce overall costs for the energy industry because, rather than creating large, expensive solar cells, you can use much smaller cells that produce just as much electricity by absorbing intensified solar energy from concentrating lenses. And concentrating lenses are relatively inexpensive.

What’s more, gallium arsenide is not exactly cheap to produce at the time. However, with constant refinements being made in industrial production processes, we can expect the cost of these to come down as well. As with everything else with solar power and renewable energy, its only a matter of time…

Source: gizmag.com