By Phil Plait August 12, Over the course of three more years, we did it five more times.
This observation was quickly interpreted as galaxies receding from earth. If earth is not in some special, privileged, central position in the universe, then it would mean all galaxies are moving apart, and the further away, the faster they are moving away.
It is now understood that the universe is expanding, carrying the galaxies with it, and causing this observation. Many other observations agree, and also lead to the same conclusion. However, for many years it was not clear why or how the universe might be expanding, or what it might signify.
Based on a huge amount of experimental observation and theoretical work, it is now believed that the reason for the observation is that space itself is expanding, and that it expanded very rapidly within the first fraction of a second after the Big Bang.
This kind of expansion is known as the "metric expansion". In mathematics and physics, a " metric " means a measure of distance, and the term implies that the sense of distance within the universe is itself changing, although at this time it is far too small an effect to see on less than an intergalactic scale.
Hubble space telescope essay modern explanation for the metric expansion of space was proposed by physicist Alan Guth inwhile investigating the problem of why no magnetic monopoles are seen today.
Guth found in his investigation that if the universe contained a field that has a positive-energy false vacuum state, then according to general relativity it would generate an exponential expansion of space.
It was very quickly realized that such an expansion would resolve many other long-standing problems. These problems arise from the observation that to look like it does today, the universe would have to have started from very finely tunedor "special" initial conditions at the Big Bang.
Inflation theory largely resolves these problems as well, thus making a universe like ours much more likely in the context of Big Bang theory. No field responsible for the cosmic inflation has been discovered. However such a field, if found in the future, would be scalar.
The first similar scalar field proven to exist was only discovered in - and is still being researched. So it is not seen as problematic that a field responsible for cosmic inflation and the metric expansion of space has not yet been discovered.
The proposed field and its quanta the subatomic particles related to it have been named inflaton. If this field did not exist, scientists would have to propose a different explanation for all the observations that strongly suggest a metric expansion of space has occurred, and is still occurring much more slowly today.
Overview of metrics and comoving coordinates[ edit ] Main articles: Metric mathematics and tensor To understand the metric expansion of the universe, it is helpful to discuss briefly what a metric is, and how metric expansion works. A metric defines the concept of distanceby stating in mathematical terms how distances between two nearby points in space are measured, in terms of the coordinate system.
Coordinate systems locate points in a space of whatever number of dimensions by assigning unique positions on a grid, known as coordinatesto each point.
GPSlatitude and longitudeand x-y graphs are common examples of coordinates. A metric is a formula which describes how a number known as "distance" is to be measured between two points.
It may seem obvious that distance is measured by a straight line, but in many cases it is not. For example, long haul aircraft travel along a curve known as a " great circle " and not a straight line, because that is a better metric for air travel. A straight line would go through the earth.
Another example is planning a car journey, where one might want the shortest journey in terms of travel time - in that case a straight line is a poor choice of metric because the shortest distance by road is not normally a straight line, and even the path nearest to a straight line will not necessarily be the quickest.
A final example is the internetwhere even for nearby towns, the quickest route for data can be via major connections that go across the country and back again. In this case the metric used will be the shortest time that data takes to travel between two points on the network.
In cosmology, we cannot use a ruler to measure metric expansion, because our ruler will also be expanding extremely slowly. Also any objects on or near earth that we might measure are being held together or pushed apart by several forces which are far larger in their effects.
So even if we could measure the tiny expansion that is still happening, we would not notice the change on a small scale or in everyday life.
On a large intergalactic scale, we can use other tests of distance and these do show that space is expanding, even if a ruler on earth could not measure it.
The metric expansion of space is described using the mathematics of metric tensors.Hubble Space Telescope The most famous space telescope is the Hubble Space Telescope.
Hubble Telescope was launched April 24, and has had more than million observations for 25 years which have changed how we see the universe and is one of the biggest advances in astronomy.
/5(4). Oct 17, · "Gravity" is the most realistic space movie ever. I mean, that Clooney guy looks just like me!
Actually I've been besieged with questions about what I thought about this movie ever since it . In , Edwin Hubble discovered that light from remote galaxies was redshifted; i.e. the more remote galaxies were, the more shifted was the light coming from timberdesignmag.com observation was quickly interpreted as galaxies receding from timberdesignmag.com earth is not in some special, privileged, central position in the universe, then it would mean all galaxies are moving apart, and the further away, the.
Hubble Space Telescope Essay Examples. 8 total results. An Overview of the Stars in the Orion's Belt. 1, words. 3 pages. An Introduction to the History of Space Travel. words. 1 page.
The Features of the Hubble Space Telescope. words. 2 pages. A Report on the Hubble Space Telescope Project. A radio astronomer in British Columbia, Canada has detected one of lowest radio frequency signals ever found to emanate from space and reach the timberdesignmag.comists are baffled by the mysterious and intense Fast Radio Bursts (FRBs) and are actively seeking a more definitive explanation.
Physicist and futurist, Dr. Michio Kaku joins Shepard Smith on FOX NEWS at the forefront of the findings to.
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