History Of Cosmology & Astronomy
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, according to The Royal Society . 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, according to Scientific American . 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.
What Is The Universe Real Physics Has Some Mind
Science says the universe could be a hologram, a computer program, a black hole or a bubbleand there are ways to check
The questions are as big as the universe and as old as time: Where did I come from, and why am I here? That may sound like a query for a philosopher, but if you crave a more scientific response, try asking a cosmologist.
This branch of physics is hard at work trying to decode the nature of reality by matching mathematical theories with a bevy of evidence. Today most cosmologists think that the universe was created during the big bang about 13.8 billion years ago, and it is expanding at an ever-increasing rate. The cosmos is woven into a fabric we call space-time, which is embroidered with a cosmic web of brilliant galaxies and invisible dark matter.
It sounds a little strange, but piles of pictures, experimental data and models compiled over decades can back up this description. And as new information gets added to the picture, cosmologists are considering even wilder ways to describe the universeincluding some outlandish proposals that are nevertheless rooted in solid science:
The universe is a hologram
Look at a standard hologram, printed on a 2D surface, and youll see a 3D projection of the image. Decrease the size of the individual dots that make up the image, and the hologram gets sharper. In the 1990s, physicists realized that something like this could be happening with our universe.
The universe is a computer simulation
How Physics Is Used In Universe And Space Science
Physics is integral to space science, because if we don’t understand how our universe works, we can’t begin to explore it. … Understanding the composition of stars and planets and how they form allows astrobiologists to talk competently about the elements that may be present in different parts of the solar system.
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Energy Needs Vs Cleaner Greener Technologies
A growing population requires more energy needs, but the needs of climate change mitigation mean we must do everything we can to reduce our energy consumption. There may seem to be a conflict, and there is to a certain degree, but advances are already being made through applied physics. Batteries, power cells and other energy storage methods are able to store more power than ever before, while our electronic devices get more powerful every day will reducing power consumption. In future, we expect new advances in physics and chemistry to reduce energy consumption further still – from LEDs that emit powerful lights at much lower consumption, but also more efficient solar paneling and electrical vehicles. Physics has helped meteorology and climatology to develop wind turbines, solar physics to develop solar arrays and paneling, and harnessed water physics to develop tidal power, hydroelectricity and other water-based technologies that harness energy from the movement of fluid. It has also developed nuclear power what new technologies lie for the remainder of the 21st century will only build on our growing energy needs for a growing population.
How Astronomers Revolutionized Our View Of The Cosmos
The universe turns out to be much bigger and weirder than anyone thought
In 1835 French philosopher Auguste Comte asserted that nobody would ever know what the stars were made of. We understand the possibility of determining their shapes, their distances, their sizes and their movements, he wrote, whereas we would never know how to study by any means their chemical composition, or their mineralogical structure, and, even more so, the nature of any organized beings that might live on their surface.
Our first hint of the true nature of stars came in 1860, when Gustav Kirchhoff recognized that the dark lines in the spectrum of light coming from the sun were caused by different elements absorbing specific wavelengths. Astronomers analyzed similar features in the light of other bright stars and discovered that they were made of the same materials found on Earthnot of some mysterious fifth essence as the ancients had believed.
But it took longer to understand what fuel made the stars shine. Lord Kelvin calculated that if stars derived their power just from gravity, slowly deflating as their radiation leaked out, then the sun’s age was 20 million to 40 million yearsfar less time than Charles Darwin or the geologists of the time inferred had elapsed on Earth. In his last paper on the subject, in 1908, Kelvin inserted an escape clause stating that he would stick by his estimate unless there were some other energy source laid up in the storehouse of creation.
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What Role Does Nasa Play In Science
In addition to investigating earth science, planetary science, heliophysics and astrophysics, NASA scientists are also dedicated to answering some of humanitys greatest questions.Besides exploring the strange world of space, our science research also helps us adapt to the changing nature of life here on Earth.
Connecting Ultrasmall And Ultralarge
Cosmic questions find answers in fundamental physics. The structure of the Universe was imprinted in its earliest moments, when the Big Bang created conditions so extreme that they challenge our understanding and imagination.
Powerful ideas from the Core, and unification beyond, help us rise to the challenge.
Why is there something rather than nothing? What is the dark matter? Does the Universe undergo violent upheavals, which change its basic character? Is everything we’ve seen only a small part of a vastly larger Multiverse? These are some of the questions we’re wrestling with.
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Telescopes To Help Decode The Cosmos
Astronomy & Physics
5/02/2019By |Jackie Swift,Cornell Research
As humans, we have an insatiable desire to understand the cosmos and our place in it. How did the universe begin and how did it evolve? What is the nature of dark matter and dark energy? How will it all end? These are the most fundamental questions one can ask, says Steve Kang Hoon Choi, Cornell Presidential Postdoctoral Fellow. If we believe greater knowledge betters our lives, then this is what drives us to study the cosmos. Choi’s work is featured in this Cornell Research story.
Choi has been drawn to the night sky and the mysteries it holds since he was in middle school. In the summer of 2018, he came to Cornell as one of the inaugural group of Cornell Presidential Postdoctoral Fellows to work with Michael D. Niemack, professor of physics, and Gordon J. Stacey, professor of astronomy, on new telescope projects that may help shed light on some of the biggest cosmological puzzles.
Read the entire story on Cornell Research.
Searching In The Dark
Particle physicists and astrophysicists both think about dark matter and dark energy. Astrophysicists want to know what made up the early universe and what makes up our universe today. Particle physicists want to know whether there are undiscovered particles and forces out there for the finding.
Dark matter makes up most of the matter in the universe, yet no known particles in the Standard Model have the properties that it should possess, says Michael Peskin, a professor of theoretical physics at SLAC. Dark matter should be very weakly interacting, heavy or slow-moving, and stable over the lifetime of the universe.
There is strong evidence for dark matter through its gravitational effects on ordinary matter in galaxies and clusters. These observations indicate that the universe is made up of roughly 5 percent normal matter, 25 percent dark matter and 70 percent dark energy. But to date, scientists have not directly observed dark energy or dark matter.
This is really the biggest embarrassment for particle physics, Peskin says. However much atomic matter we see in the universe, theres five times more dark matter, and we have no idea what it is.
But scientists have powerful tools to try to understand some of these unknowns. Over the past several years, the number of models of dark matter has been expanding, along with the number of ways to detect it, says Tom Rizzo, a senior scientist at SLAC and head of the theory group.
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Changing Models Changing Ideas
Scientific knowledge is always open to revision. Thechanging models of the cosmos show how scientistsreassess and revise scientific knowledge. Studyingselect primary sources in chronological order canilluminate how ideas of the structure of the universehave developed over time.
A comparison of models from different eras canreveal the gradual shift from an Earth-centereduniverse to a sun-centered solar system, thediscovery of new planets and moons orbiting otherplanets, and eventually the understanding that oursolar system is just one of many in our galaxy.These sources clearly show that ideas changegradually–even once new discoveries are made.Older models of the universe persisted for centurieseven after new evidence contradicted them.Seemingly contradictory ideas about the cosmosstill exist today.
How Does The Sun Help Us Understand The Rest Of The Galaxy
A normal star is the sun.The sun is much closer to us than any other star, so by studying it, we can acquire a more complete understanding of our planet.As we expand our understanding of other stars, we come to know more about the Milky Way.After that, we acquire more knowledge of other galaxies, and we gain more insight into other universes.
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Light And Communication Systems
The collection and sharing of information are of the most essential aspects of any form of scientific development, as they are critical to collaboration. Modern wireless technologies have helped us develop communication systems like the internet and telephone, which have increased the pace and quality of communication to unprecedented levels. And we were able to come about such systems through our increased understanding of light.
How Physics Applies To Environmental Science
No other science can get away from physics because all matter is made up of molecules. As physics is the study of how matter acts and reacts to various forcings and aspects of the world and the universe, physics has massive implications for the environmental sciences.
Climate change: Although few physicists deliberately aim to become climatologists, many today are working on some of the fundamental problems caused by our changing climate and examining potential solutions . The physics of our environment, atmosphere and ocean cycle system temperature rises all dictate a number of things such as the fluid movements of water systems such as oceanic oscillations, and how environments will react to atmospheric chemistry changes. Physics will show how climates will change and the long-term effects on both land and aquatic ecologies.
Renewable energy: The contribution of physics to the environmental sciences is no better demonstrated than in the development of renewable energy. For example, solar panels and solar arrays convert light and heat into electricity through chemical processes that we have identified through physics . Also, physics has been fundamental in developing turbines – the science behind wind farms that also generate electricity. Finally, physics can be used to calculate the amount of energy produced by the processing and burning of biofuel just as it has for fossil fuels.
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More Accurate Estimates Throw Current Models Off
Astronomers have made the most precise measurements to date of the expansion rate of the universe and are now turning to some weird new physics to explain the results.
The study, to be published soon in The Astrophysical Journal, used the Hubble Space Telescope to show that the universe is flying apart faster than expected. The newly-measured rate of expansion doesnt match up with predictions obtained via other methods, which may mean that there is something amiss with our current models of the universe.
The community is really grappling with understanding the meaning of this discrepancy, says Adam Riess, lead author and researcher the Space Telescope Science Institute and Johns Hopkins University, both in Baltimore, US.
The rate of the universes expansion over time is called the Hubble constant. Measurements of the constants value have differed wildly, and over the past decades astronomers have been striving to narrow down its true value.
In this study, astronomers used the Hubble Space Telescope to measure the distances to other galaxies by studying Cepheid variables. This is a class of stars that change their brightness in a predictable way, allowing astronomers to infer their distance from Earth. Cepheid variables have been used to estimate the Hubble constant before, but this time the team looked at Cepheids up to 10 times farther into space, between 6000 and 12,000 light-years away.
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Daniele Malafarina Associate Professor From Nazarbayev University School Of Sciences And Humanities Unpacks Astrophysics For Us In This Insightful Article
For most of history, looking at the cosmos was done with the naked eye, without instruments, and the main purpose of observations were to keep track of the movements of celestial bodies. Astronomy did not tell us anything about the nature of the objects being observed, namely the stars and planets.
Since the time of Galileo, Newton, Kepler, and other pioneers of the scientific revolution, we started looking at the cosmos using instruments and applying the laws of physics to make sense of what the instruments measure. This allowed us to understand what astronomical objects are, how they form and evolve, and this is the core of what astrophysics is: Using the laws of physics applied to observations of phenomena in the universe to understand their nature and evolution.
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S Toward Quantum Gravity In A Realistic Cosmos
- Society of Fellows, Harvard University, Cambridge, MA, USA
Experimental discoveries in the late 1990s established that we live in a Universe undergoing accelerating expansion . Our prevailing understanding of cosmology posits that this accelerating expansion is due to empty space possessing an energy, described by a positive cosmological constant. A positive cosmological constant is a major challenge for quantum gravity theorists to understand. They have had more success with the imagined setting of a negative cosmological constant. While quantum gravity models with a negative cosmological constant do not describe our Universe, they do have a surprising feature: the gravity-filled volume of spacetime can be described by a field theory without gravity, often envisioned as a hologram living on a surface. Inspired by this framework, Yasuaki Hikida from Kyoto University in Japan and colleagues studied a simplified model of an expanding universe and found that it also has holographic properties . Their findings may offer a new direction for theorists trying to build models of quantum gravity with a positive cosmological constant consistent with our own Universe.
Who Is This Course Suitable For
This course is suitable for anyone interested in exploring the biggest questions about the universe.
You may be about to embark on further studies in physics, astrophysics, or cosmology and keen to gain insight into areas you might pursue and to enhance your university application.
Alternatively, you may be a life-long learner, and interested in developing the knowledge and skills required to engage with and understand scientific literature on the subject.
This course has been certified by the CPD Certification Service as conforming to continuing professional development principles. Find out more.
After completing the course, you will be issued with a digital certificate. This can be used as evidence to show during job and university applications, or appraisals.
Mysteries Of Modern Cosmology
Though cosmology has advanced much over the last century, there are still several open mysteries. In fact, two of the central mysteries in modern physics are the dominant problems in cosmology and astrophysics:
- Dark Matter – Some galaxies are moving in a way that cannot be fully explained based on the amount of matter that is observed within them , but which can be explained if there is an extra unseen matter within the galaxy. This extra matter, which is predicted to take up about 25% of the universe, based on most recent measurements, is called dark matter. In addition to astronomical observations, experiments on Earth such as the Cryogenic Dark Matter Search are trying to directly observe dark matter.
- Dark Energy – In 1998, astronomers attempted to detect the rate at which the universe was slowing down … but they found that it wasn’t slowing down. In fact, the acceleration rate was speeding up. It seems that Einstein’s cosmological constant was needed after all, but instead of holding the universe as a state of equilibrium it actually seems to be pushing the galaxies apart at a faster and faster rate as time goes on. It’s unknown exactly what is causing this “repulsive gravity,” but the name physicists have given to that substance is “dark energy.” Astronomical observations predict that this dark energy makes up about 70% of the universe’s substance.