THE UNIVERSE OR DECREASING ACCELERATION IS THE EXPANSION RATE PRESENTED BY: JAKE DOTTS & JESS MYERS

NEWTON’S CONTRIBUTIONS For a long time, it has been widely accepted that the universe is expanding. Isaac Newton claimed that every object was attracted to each other because of the law of gravity — yet if this were the case, everything in the universe would collide with one another. ISAAC NEWTON

EINSTEIN’S CONTRIBUTIONS ALBERT EINSTEIN Einstein figured out that gravity is due to the curvature of space time, and he applied this theory to cosmology (the study of the origin and development of the universe). This created a dynamic equation correlating the reaction of gravity with that of the curvature of the universe. However, he made a great error in thinking that the universe was static — that is, that it was unchanging in its entirety.

SLIPHER’S CONTRIBUTIONS VESTO SLIPHER However, between 1912 and 1922, Vesto Slipher made an important discovery: the wavelengths of light spectra are systematically redshifting. This means that the light from objects shifts to longer wavelengths, allowing for the measurement of distance between the observer and the object due to Einstein’s equations involving gravity.

HUBBLE’S CONTRIBUTIONS EDWIN HUBBLE Lastly, in 1929 Hubble figured out that the redshift of an object correlates directly with an increasing linear function — that is, distance between objects seemed to be increasing. The universe was currently expanding. However, the notion was that this expansion was not increasing, but rather decreasing — indeed the universe was still getting bigger, but less and less with time.

PRESENT PIONEERS In 2011, the Nobel Prize in Physics was divided amongst three scientists: Saul Perlmutter receiving half of the awards credit, while Brian P. Schmidt, and Adam G. Riess split the remained. The award was received for their discovery of proof that the universe is not only expanding, but is indeed accelerating positively in size. SAUL PERLMUTTER BRIAN P. SCHMIDTADAM G. REISS

In Einstein’s equation relating gravity to the curvature of spacetime, two more crucial components were added: one of pressure, and one of density. This negative gravitational pressure causes things to repel from one another, while the density (if high enough) would cause things to attract one another. EINSTEIN’S MISSING LINK ALBERT EINSTEIN

The Nobel-winning scientists were on a mission to figure out whether or not the energy density of the universe was increasing, and thus continuing to expand space, or whether it was decreasing, and would lead to an eventual collapse in the future. They measured this by studying the redshift of distant stars, which can chart out a map of the history of the universe’s expansion. Upon doing this, they discovered that the universe was not expanding at a decelerating rate, but rather that it was accelerating exponentially with the passing of time. MAP OF OUR UNIVERSE’S REDSHIFT PATTERNS REDSHIFT MAPPING

In addition, they discovered that the density factor was reliant on something known as dark energy — this is the stuff in space that is dark in color, and has an energy because it has a pressure; this is the “nothingness” that one often thinks of, the total blackness surrounding galaxies and points of light. Because this energy fills in the gaps left by the expanding universe, it continues to be a constant fixture in space — and thus allows the universe to expand outward at an ever- increasing rate. DARK ENERGY OUR DARK UNIVERSE

The discovery that the universe is constantly accelerating does not have any immediate impacts. However, it brings up one very crucial and important realization: there is no time in the relatively near future, or perhaps ever, when the universe will buckle in on itself. If this were to happen the universe would become a dimensionless singularity. This process if referred to as the Big Crunch. IMPACT OF DISCOVERY THE BIG CRUNCH

INCREASING ACCELERATION Before, when the universe was thought to be slowly decelerating, the idea of a collapsing universe was very real and had to be dealt with. Now, there is no such fear — the dark energy continues to be a constant within the realms of space, and as a result, the curvature of space time is constant. The universe will continue to get larger and more expansive, doubling every 10 billion years. OUR UNIVERSE