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Wondering what the March 2014 story about the Big Bang theory means for our knowledge of our universe? Or why you're suddenly reading about "inflation" in a story about astrophysics? And just what are "cosmic ripples"?

x

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Wondering what the March 2014 story about the Big Bang theory means for our knowledge of our universe? Or why you're suddenly reading about "inflation" in a story about astrophysics? And just what are "cosmic ripples"? x

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New idea for a calendar
Bradley
http://www.popularmechanics.com/science/archaeology/a24195/case-for-a-new-calendar-12017/

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New idea for a calendar

http://www.popularmechanics.com/science/archaeology/a24195/case-for-a-new-calendar-12017/

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Crash course is a very helpful educational Chanel on YouTube. Science is one of their specialties. This is Sofia.

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Crash course is a very helpful educational Chanel on YouTube. Science is one of their specialties. This is Sofia.

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gfghghghghhG

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The Big Bang, Cosmology part 1: Crash Course Astronomy #42

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Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly its expanding also allows us to run the clock backwards 14 billion years to the way the universe began - with a bang.

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Pretty cool image that I found on the interwebs about the history of the universe
- Jordan

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In Depth Article about Nucleic Acids (Ciara)

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In Depth Article about Nucleic Acids (Ciara)

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Discussion of DNA & RNA for organic chemistry students

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Molly
https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy

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Spencer

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- H. Hansen 😊

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Welcome to the Physics library!

Physics is the study of matter, motion, energy, and force. Here, you can browse videos, articles, and exercises by topic. We keep the library up-to-date, so you may find new or improved material here over time.

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Physics library | Science | Khan Academy

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Physics the study of matter, motion, energy, and force.

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Apr 22, 2010 ... Most of these aquatic species are tied together through the food web. ... Countless billions of one-celled organisms, called phytoplankton, saturate sunlit upper- ocean waters worldwide. ... The next level of the marine food chain is made up of animals that feast on the sea's abundant plant ...

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Olivia

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Joanna

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Perimeter Institute for Theoretical Physics

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Cosmology 1 - The Basics of the Universe

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A primer on cosmology . . . KEY POINTS Matter - Atoms -- electrons, protons, neutrons - Protons and neutrons made of quarks - Things get crazy: antimatter, quark varieties, neutrinos Four Fundamental Forces - Gravity - Electromagnetic force - Strong nuclear force - Weak nuclear force REFERENCES The material for the cosmology lectures was drawn from the following books: - Paul Davies, Cosmic Jackpot (Houghton Mifflin, 2007).

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String theory with basic and advanced links

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String theory with basic and advanced links

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Halle
http://superstringtheory.com/cosmo/

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Austin

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Intro to Cosmology. There are a lot of great links in this article to check out too!

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Intro to Cosmology. There are a lot of great links in this article to check out too!

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Josiah

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Snapshot from a computer simulation of the formation of large-scale structures in the universe, showing a patch of 100 million light-years and the resulting coherent motions of galaxies flowing toward the highest mass concentration in the center.

Credit: ESO

Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. According to NASA, the definition of cosmology is "the scientific study of the large scale properties of the universe as a whole."

Cosmologists puzzle over exotic concepts like string theory, dark matter and dark energy and whether there is one universe or many (sometimes called the multiverse). While other aspects astronomy deal with individual objects and phenomena or collections of objects, cosmology spans the entire universe from birth to death, with a wealth of mysteries at every stage.

Humanity's understanding of the universe has evolved significantly over time. In the early history of astronomy, Earth was regarded as the center of all things, with planets and stars orbiting it. In the 16th century, Polish scientist Nicolaus Copernicus suggested that Earth and the other planets in the solar system in fact orbited the sun, creating a profound shift in the understanding of the cosmos. In the late 17th century, Isaac Newton calculated how the forces between planets - specifically the gravitational forces - interacted.

The dawn of the 20th century brought further insights into comprehending the vast universe. Albert Einstein proposed the unification of space and time in his General Theory of Relativity. In the early 1900s, scientists were debating whether the Milky Way contained the whole universe within its span, or whether it was simply one of many collections of stars. Edwin Hubble calculated the distance to a fuzzy nebulous object in the sky and determined that it lay outside of the Milky Way, proving our galaxy to be a small drop in the enormous universe. Using General Relativity to lay the framework, Hubble measured other galaxies and determined that they were rushing away from the us, leading him to conclude that the universe was not static but expanding.

In recent decades, cosmologist Stephen Hawking determined that the universe itself is not infinite but has a definite size. However, it lacks a definite boundary. This is similar to Earth; although the planet is finite, a person traveling around it would never find the "end" but would instead constantly circle the globe. Hawking also proposed that the universe would not continue on forever but would eventually end.

Launched in November 1989, NASA's Cosmic Background Explorer (COBE) took precise measurements of radiation across the sky. The mission operated until 1993.

Although NASA's Hubble Space Telescope is probably best known for its astounding images, a primary mission was cosmological. By more accurately measuring the distances to Cepheid variables, stars with a well-defined ratio between their brightness and their pulsations, Hubble helped to refine measurements regarding how the universe is expanding. Since its launch, astronomers have continued to use Hubble to make cosmological measurements and refine existing ones.

Thanks to Hubble, "If you put in a box all the ways that dark energy might differ from the cosmological constant, that box would now be three times smaller," cosmologist Adam Riess of the Space Telescope Science Institute said in a statement. "That's progress, but we still have a long way to go to pin down the nature of dark energy."

NASA's Wilkinson Microwave Anisotropy Probe (WMAP) was a spacecraft that operated from 2001 to 2010. WMAP mapped tiny fluctuations in the cosmic microwave background (CMB), the ancient light from the early universe, and determined that ordinary atoms make up only 4.6 percent of the universe, while dark matter makes up 24 percent.

"Lingering doubts about the existence of dark energy and the composition of the universe dissolved when the WMAP satellite took the most detailed picture ever of the cosmic microwave background," said cosmologist Charles Seife in the journal Science.

The European Space Agency's Planck space mission ran from 2009 to 2013 and continued the study of the cosmic microwave background.

The ESA is currently developing the Euclid mission, which should fly by the end of the decade. Euclid will study dark matter and dark energy with greater precision, tracing its distribution and evolution through the universe.

"At the heart of the mission is one of the billion pound questions of physics," the ESA's David Parker said in a statement.

Some researchers think concentric ring patterns in measurements of the cosmic microwave background are evidence of a universe that existed before our own was born in the Big Bang.

Credit: Roger Penrose and Vahe Gurzadyan

What came before the Big Bang?
Because of the enclosed and finite nature of the universe, we cannot see "outside" of our own universe. Space and time began with the Big Bang. While there are a number of speculations about the existence of other universes, there is no practical way to observe them, and as such there will never be any evidence for (or against!) them.

Where did the Big Bang happen?
The Big Bang did not happen at a single point but instead was the appearance of space and time throughout the entire universe at once.

If other galaxies all seem to be rushing away from us, doesn't that place us at the center of the universe?
No, because if we were to travel to a distant galaxy, it would seem that all surrounding galaxies were similarly rushing away. Think of the universe as a giant balloon. If you mark multiple points on the balloon, then blow it up, you would note that each point is moving away from all of the others, though none are at the center. The expansion of the universe functions in much the same way.

How old is the universe?
According to data released by the Planck team in 2013, the universe is 13.8 billion years old, give or take a hundred million years or so. Planck determined the age after mapping tiny temperature fluctuations in the CMB.

"Patterns over huge patches of sky tell us about what was happening on the tiniest of scales in the moments just after our universe was born," said Charles Lawrence, the U.S. project scientist for Planck, in a statement.

Will the universe end? If so, how?
Whether or not the universe will come to an end depends on its density - how spread out the matter within it might be. Scientists have calculated a "critical density" for the universe. If its true density is greater than their calculations, eventually the expansion of the universe will slow and then, ultimately, reverse until it collapses. However, if the density is less than the critical density, the universe will continue to expand forever. [More: How the Universe Will End]

Which came first, the chicken...er, the galaxy or the stars?
The post-Big Bang universe was composed predominantly of hydrogen, with a little bit of helium thrown in for good measure. Gravity caused the hydrogen to collapse inward, forming structures. However, astronomers are uncertain whether the first massive blobs formed individual stars that later fell together via gravity, or the mass came together in galaxy-sized clumps that later formed stars.

Additional reading:

Follow Nola Taylor Redd at @NolaTRedd, Facebook, or Google+. Follow us at @Spacedotcom, Facebook or Google+.

Further resources:

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Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. According to NASA, the definition of cosmology is "the scientific study of the large scale properties of the universe as a whole."

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Pretty good example of the scientific method at work in a cosmological setting

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Pretty good example of the scientific method at work in a cosmological setting

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Blaze

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Five years ago, the Nobel Prize in Physics was awarded to three astronomers for their discovery, in the late 1990s, that the universe is expanding at an accelerating pace.

Their conclusions were based on analysis of Type Ia supernovae - the spectacular thermonuclear explosion of dying stars - picked up by the Hubble space telescope and large ground-based telescopes. It led to the widespread acceptance of the idea that the universe is dominated by a mysterious substance named 'dark energy' that drives this accelerating expansion.

Now, a team of scientists led by Professor Subir Sarkar of Oxford University's Department of Physics has cast doubt on this standard cosmological concept. Making use of a vastly increased data set - a catalogue of 740 Type Ia supernovae, more than ten times the original sample size - the researchers have found that the evidence for acceleration may be flimsier than previously thought, with the data being consistent with a constant rate of expansion.

The study is published in the Nature journal Scientific Reports.

Professor Sarkar, who also holds a position at the Niels Bohr Institute in Copenhagen, said, "The discovery of the accelerating expansion of the universe won the Nobel Prize, the Gruber Cosmology Prize, and the Breakthrough Prize in Fundamental Physics. It led to the widespread acceptance of the idea that the universe is dominated by "dark energy" that behaves like a cosmological constant - this is now the "standard model" of cosmology."

"However, there now exists a much bigger database of supernovae on which to perform rigorous and detailed statistical analyses. We analysed the latest catalogue of 740 Type Ia supernovae - over ten times bigger than the original samples on which the discovery claim was based - and found that the evidence for accelerated expansion is, at most, what physicists call "3 sigma". This is far short of the "5 sigma" standard required to claim a discovery of fundamental significance."

According to Professor Sarkar, "An analogous example in this context would be the recent suggestion for a new particle weighing 750 GeV based on data from the Large Hadron Collider at CERN. It initially had even higher significance - 3.9 and 3.4 sigma in December last year - and stimulated over 500 theoretical papers. However, it was announced in August that new data shows that the significance has dropped to less than 1 sigma. It was just a statistical fluctuation, and there is no such particle."

There is other data available that appears to support the idea of an accelerating universe, such as information on the cosmic microwave background - the faint afterglow of the Big Bang - from the Planck satellite.

However, Professor Sarkar said. :All of these tests are indirect, carried out in the framework of an assumed model, and the cosmic microwave background is not directly affected by dark energy. Actually, there is indeed a subtle effect, the late-integrated Sachs-Wolfe effect, but this has not been convincingly detected."

"So it is quite possible that we are being misled and that the apparent manifestation of dark energy is a consequence of analysing the data in an oversimplified theoretical model - one that was in fact constructed in the 1930s, long before there was any real data. A more sophisticated theoretical framework accounting for the observation that the universe is not exactly homogeneous and that its matter content may not behave as an ideal gas - two key assumptions of standard cosmology - may well be able to account for all observations without requiring dark energy. Indeed, vacuum energy is something of which we have absolutely no understanding in fundamental theory.," Professor Sarkar said.

Professor Sarkar added: "Naturally, a lot of work will be necessary to convince the physics community of this, but our work serves to demonstrate that a key pillar of the standard cosmological model is rather shaky. Hopefully this will motivate better analyses of cosmological data, as well as inspiring theorists to investigate more nuanced cosmological models. Significant progress will be made when the European Extremely Large Telescope makes observations with an ultrasensitive "laser comb" to directly measure over a ten to 15-year period whether the expansion rate is indeed accelerating."

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Doubts Raised That Universe Is Expanding At An Accelerating Rate

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Five years ago, the Nobel Prize in Physics was awarded to three astronomers for their discovery, in the late 1990s, that the universe is expanding at an accelerating pace. Their conclusions were based on analysis of Type Ia supernovae - the spectacular thermonuclear explosion of dying stars - picked up by the Hubble space telescope and large ground-based telescopes.

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https://www.grc.nasa.gov/www/k-12/airplane/thermo.html

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Logan

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Logan

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Pretty good article that is an advanced/in-depth insight into energy flow
Logan

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The Habitable Planet Unit 4 - Ecosystems // Online Textbook

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Teacher resources and professional development across the curriculum

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Good pic of pathway of energy through an ecosystem

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Good pic of pathway of energy through an ecosystem

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Logan