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The big bang and our expanding universe

The big bang and our expanding universe


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The Hubble telescope can see the light from the big bang.My question is if our universe is expanding that would make everything that's in front of our solar system be in the future? And also can Hubble see ahead of our solar system and does the bang big light ends behind our solar system?


There are a couple of misunderstandings here. Let's take one at a time:

The Hubble telescope can see the light from the big bang.

The Hubble Space Telescope (HST) doesn't actually see light from the Big Bang. HST has several instruments on board, both for imaging and spectroscopy, but they all operate in the infrared, optical (i.e. "visible to humans"), and ultraviolet wavelength range. When you mention "light from the Bing Bang", I suppose you're thinking of the cosmic microwave background radiation (CMB), which is light emitted 380,000 after Big Bang. This is "the closest" we can get to Big Bang (yet). HST is unable to detect microwaves; instead we have other telescopes for that, the most recently-launched being Planck.

My question is if our universe is expanding that would make everything that's in front of our solar system be in the future?

The expansion of the Universe is one of the most difficult concepts to get one's head around. But firstly, Big Bang wasn't an explosion, hurling matter outwards from a central point in an otherwise empty Universe. Galaxies, on average, don't travel much through space. Rather, they lie relatively still in space, but space itself expands. The distances between galaxies increase all the time, and previously, before galaxies were formed, the distance between atoms and other particles increased. An often-used analogy - which you shouldn't take too far - is a balloon with dots painted on. The dots are fixed on its surface, and when you blow it up, the distances between the dots increase despite the dots still being fixed.

Secondly, your question seems to confuse space and time. Even if the expansion were an explosion, we would travel through space, and yes, you could say that we travel through time as well, but saying that the future is "everything in front of our Solar system" doesn't really make sense (to me, at least). What's in front of you when you travel through space is just more space; you can look at it before you get there, but that doesn't mean you look into the future (in fact you look at the past, since the light you detect with your eyes has spent some time traveling toward you).

And also can Hubble see ahead of our solar system

It depends what you mean by "ahead". It can definitely see things outside the Solar system. The Solar system consists of one star and it satellites (planets, comets, asteroids, etc.) out of the few hundred billions that make up the galaxy we call the Milky Way. Our Galaxy is itself only one out of at least some hundred billion - and quite possibly infinitely many - galaxies that float around in our Universe. And yes, HST can see many of these. But if by "ahead" you mean "into the future", then the answer is no.

and does the bang big light ends behind our solar system?

As mentioned above, the Big Bang light - or the CMB - was emitted shortly after Big Bang. That means that it has been traveling for 13.8 billion years through space. Light travels one lightyear per year, but since the Universe is expanding, the distance that the CMB has traveled is more than 13.8 billion lightyears; in fact it's some 46 billion lighyears. This is the most distant "thing" we can see, way, way beyond the Solar system which for comparion is of the order of one lightyear large.


The 1st microsecond of the Big Bang

What was the universe like just after the Big Bang? Cosmologists probe basic physics during that earliest time using particle accelerators. The biggest one in the world is the Large Hadron Collider at CERN, a tunnel 17 miles (27 km) in circumference, deep underground beneath the border of France and Switzerland. On May 31, 2021, researchers said they used the Large Hadron Collider to investigate a specific kind of plasma present during the first millionth of a second – aka the first microsecond, or 0.000001 second – of the Big Bang. They said this plasma was the first matter ever to be present in our universe. And, they said, it had liquid-like properties.

The peer-reviewed journal Physics Letters B has published this new work online for its July 10, 2021, issue. You Zhou, together with his student Zuzana Moravcova, both at the Niels Bohr Institute at the University of Copenhagen, performed the work.

Quark–gluon plasma

Plasmas are sometimes called a fourth state of matter after solids, liquids and gases. The plasma in the earliest universe is called a quark–gluon plasma (QGP).

Modern researchers believe it was present in the first 0.000001 second of the Big Bang.

So imagine the state of matter in our present-day expanding universe. Then “run the movie backwards” in your mind, imagining all the galaxies getting closer and closer together as we look back in time. You might see that, during the first microsecond of the Big Bang, everything we know was crushed into an inconceivably small volume.

And perhaps you’ll also see that those first microseconds of our universe were incredibly hot and dense. It’s in this earliest time that we find the quark–gluon plasma. The video below, from Fermilab’s Don Lincoln, has more to say about this particular plasma.

Keep reading, to learn what the scientists at the Niels Bohr Institute learned about it.

Our universe’s 1st microsecond

The quark-gluon plasma (QGP) – present in the first 0.000001 second of Big Bang – didn’t stay around long. After those earliest moments, it disappeared as the universe expanded, becoming less hot and less dense. It’s a triumph of modern science that scientists can study the physics of this plasma using the Large Hadron Collider. Particle physicist You Zhou explained:

We have studied a substance called quark-gluon plasma that was the only matter which existed during the first microsecond of the Big Bang. Our results tell us a unique story of how the plasma evolved in the early stage of the universe.

First the plasma that consisted of quarks and gluons was separated by the hot expansion of the universe. Then the pieces of quark reformed into so-called hadrons. A hadron with three quarks makes a proton, which is part of [the cores of atoms].

These cores are the building blocks that constitute Earth, ourselves and the universe that surrounds us.

He explained how the Large Hadron Collider at CERN enabled researchers to recreate this first matter in history and trace back what happened to it:

The collider smashes together ions from the plasma with great velocity, almost like the speed of light [186,000 miles per second, or 300,000 km per second]. This makes us able to see how the QGP evolved from being its own matter to the cores in atoms and the building blocks of life.

A liquid-like form for the earliest matter

This team of scientists developed an algorithm that showed how the QGP expanded as the microseconds ticked by and the universe as a whole expanded. Their results showed that the QGP used to have a liquid-like form. The scientists said that it:

… distinguishes itself from other matters by constantly changing its shape over time.

For a long time researchers thought that the plasma was a form of gas, but our analysis confirm the latest milestone measurement, where the Hadron Collider showed that QGP was fluent and had a smooth soft texture like water.

The new details we provide is that the plasma has changed its shape over time, which is quite surprising and different from any other matter we know and what we would have expected.

He commented that, though this new work might seem like a small detail, it brings scientists a step closer to solving the puzzle of the Big Bang and of how the universe developed in its first microsecond.

Particle physicist You Zhou. Image via the Niels Bohr Institute at the University of Copenhagen. Zuzana Moravcova is a Ph..D fellow in experimental particle physics at the Niels Bohr Institute. Image via the University of Copenhagen.

Bottom line: Using data produced by the Large Hadron Collider, scientists say that in the Big Bang’s first microsecond quark-gluon plasma took the form of a liquid.


The big bang and our expanding universe - Astronomy

Could we say that the Big Bang is still happening? I mean, isn't the observed expansion of the Universe the Big Bang in action? In other words, if we draw planets, stars, galaxies, star systems on a piece of paper and then crush the sheet into a ball and leave it, it will slowly begin to unfold and this will happen for a while. If we are patient enough we can see the sheet of paper unfolded again, as it was in the first moment.

Ever since the big bang happened our universe has been expanding. As a matter of fact, the continued large-scale expansion of the universe is one of our best arguments for why we know that our universe started from a very small dense state.

But while we continue to see other galaxies flying away from us faster and faster our own milky way galaxy and all the stars, planets, humans and paper balls inside of it are bound by local forces that are far stronger. Our stars and planets hold together by gravity, so while the universe at large will continue to grow on large scales our solar system will stay at the same size. Similarly, humans and paper are held together by electromagnetic forces. So to answer your question: a piece of paper on earth does not expand over time, to see the effects of the big bang we need to observe faraway galaxies.

Thanks for your great question, the expansion of the universe is a fascinating thing to think about since it is so different from our everyday life.


The big bang and our expanding universe - Astronomy

In previous chapters, we explored the contents of the universe—planets, stars, and galaxies—and learned about how these objects change with time. But what about the universe as a whole? How old is it? What did it look like in the beginning? How has it changed since then? What will be its fate?

Cosmology is the study of the universe as a whole and is the subject of this chapter. The story of observational cosmology really begins in 1929 when Edwin Hubble published observations of redshifts and distances for a small sample of galaxies and showed the then-revolutionary result that we live in an expanding universe—one which in the past was denser, hotter, and smoother. From this early discovery, astronomers developed many predictions about the origin and evolution of the universe and then tested those predictions with observations. In this chapter, we will describe what we already know about the history of our dynamic universe and highlight some of the mysteries that remain.

Figure 1. Space Telescope of the Future: This drawing shows the James Webb Space Telescope, which is currently planned for launch in 2018. The silver sunshade shadows the primary mirror and science instruments. The primary mirror is 6.5 meters (21 feet) in diameter. Before and during launch, the mirror will be folded up. After the telescope is placed in its orbit, ground controllers will command it to unfold the mirror petals. To see distant galaxies whose light has been shifted to long wavelengths, the telescope will carry several instruments for taking infrared images and spectra. (credit: modification of work by NASA)


How numbers link universe to universe

But how does one universe transition to another? For the last two years, I have been trying to answer that question from a rigorous mathematical perspective. I apply mathematical techniques from the field of regularization theory within the field of celestial mechanics, and try and see if a cyclic universe is even mathematically possible.

This is done by showing that the equations defining the Big Bang can be rewritten so as to make sense at the moment of the Big Bang. This is necessary, since the equations defining the evolution of the universe after the Big Bang, called the Friedmann equations, break down at the Big Bang itself and make no sense. [Hidden Time in the Art of Ed Belbruno (Photos)]

Regularization theory provides a way for these equations to be rewritten in a new form so they can be defined at the Big Bang. If this is done correctly, then it also provides a way to understand if variation in the parameters defining the universe can be described at and near the Big Bang as time varies. We then say that the Big Bang has been "regularized." Once this is done, then it can be determined if it is mathematically possible for a transition from a big crunch to a Big Bang to occur.

The way the way regularization works is as follows: The Friedmann equations describe the evolution of the universe from the Big Bang as time progresses. They are obtained using Einstein's general theory of relativity and yield values that describe the evolution of several different parameters as time varies. The variables include the Hubble variable, which describes rate of change of the scale of the universe, and the "equation of state," which is the ratio of the pressure and the density of the universe.

There are several others, including the curvature of the universe, which measures the degree to which the universe bends space and time, and the anisotropy, which is a measure of how nonuniform the universe is in different directions. Although there are several parameters of interest, the key ones for my analysis are the Hubble variable and the equation of state. This is because I am concerned with how the universe behaves at and near the Big Bang. The Hubble variable is important since it is related to the scale, or size, of the universe and how that varies. The equation of state is important since it yields values it must have for regularization to be possible. These two variables give a pretty good picture of what is going on.


How the Big Bang Theory Works

Some cosmologists use the big bang theory to estimate the age of the universe. But due to different measurement techniques, not all cosmologists agree on the actual age. In fact, the range spans more than a billion years!

The discovery that the universe is expanding led to another question. Will it expand forever? Will it stop? Will it reverse? According to the general theory of relativity, it all depends on how much matter is within the universe.

It boils down to gravity. Gravity is the force of attraction between particles of matter. The amount of gravitational force one body exerts on another depends upon the size of the two objects and the distance between them. If there's enough matter in the universe, the force of gravity will eventually slow the expansion and cause the universe to contract. Cosmologists would designate this as a closed universe with positive curvature. But if there isn't enough matter to reverse expansion, the universe will expand forever. Such a universe would either have no curvature or negative curvature. To learn more about curvature of the universe, read "Does space have a shape?"

If we are in a closed universe, eventually the entire universe will contract and collapse in on itself. Cosmologists call this the big crunch. Some theorize that our universe is just the latest in a series of universes generated in a cycle of space expanding and contracting.

According to the big bang theory, there's no center of the universe. Every point in the universe is the same as every other point, with no centralized location. This is difficult to imagine, but it's a requirement for a universe that is both homogeneous and isotropic. From our perspective, it seems like everything in the universe is moving away in the manner suggested by the big bang. One alternative theory is that the Earth itself is the center of the universe, which would explain why everything else is moving away. Cosmologists dismiss this theory because it's extremely unlikely that we'd occupy the central point of the entire universe.

There are also some very big questions the big bang theory doesn't address:

  • What happened before the big bang? According to our understanding of science, we can't know. The very laws of science break down as we approach t = 0 seconds. In fact, since the general theory of relativity tells us that space and time are coupled, time itself ceases to exist. Since the answer to this question lies outside the parameters of what science can address, we can't really hypothesize about it.
  • What lies beyond the universe? Again, this is a question science can't address. That's because we can't observe or measure anything that lies outside the boundaries of the universe. The universe may or may not be expanding within some other structure, but it's impossible for us to know either way.
  • What is the shape of the universe? There are many theories about what shape the universe might have. Some believe that the universe is unbounded and shapeless. Others think the universe is bounded. The big bang theory doesn't specifically address the issue.

Not everyone subscribes to the big bang theory. Why do they disagree with the theory, and what are some of the alternate models for our universe? Read on to see what the skeptics say.


Big Bang, beginning of the Universe

The universe, as we see it today, is expanding from a widely accepted theoretical event in spacetime called the Big Bang that occurred approximately 13.7 billion years ago.

We have observed that galaxy clusters, including our own, have been receding from each other. A common analogy applied to our expanding universe is of a spotted balloon being blown up. As the balloon expands, so too does the distance between the spots. This increased distance is obviously and evidently true when applied to the many galaxy clusters within our universe.

We watch the galaxies recede from us and believe ourselves to be stationary however, this is just our relative view of the universe. For example, a galaxy receding from us at a rate of 'x' km/sec would see our galaxy moving away from itself at that same speed. Some galaxies do not recede from each other because their gravity holds them together. These are the galactic groups called 'clusters'.

If another galaxy's speed is increasing with respect to its distance from our own Milky Way, the other galaxy will inevitably reach 'lightspeed' and in effect will no longer be observable. This distance, the boundary of the observable universe, is not the end of the universe itself but is assumed to be somewhere in the region of 15 to 20 billion light-years away, a distance we have yet to penetrate.

In 1929 Edwin Hubble, an American astronomer, discovered that galaxies all around us were receding, because light analyzed from each galaxy was red-shifted (the absorption lines were shifted to the red side of the spectrum, an effect known as the Doppler Effect, indicating that the light sources were moving away our galaxy). Edwin hypothesized that the further the galaxy, the faster its recession from earth this became known as the Hubble Constant (Ho).

The equation for the Hubble Constant (Ho = v/d) is simple in form but extremely hard to specify because the figures are largely inaccurate (v is a galaxy's radial outward velocity i.e. the motion of the galaxy from our line-of-sight, and d is that galaxy's distance from the Earth). An accurate result relies on the precision of the values obtained for v and d (d is the more difficult of the two since reliable distance markers - such as variable stars and supernovae - must be found in galaxies to determine their distances).

Even today an exact figure for the Hubble Constant cannot be agreed upon. Two teams of researchers assigned to finding the Hubble constant have conflicting results. The first team - associated with Allan Sandage of the Carnegie Institutions - has obtained a value of 57 km/sec/Mpc using Type 1a supernovae. The second team - associated with Wendy Freedman of the same Institution - has obtained a value of

70 km/sec/Mpc using Cepheids and the Hubble Space Telescope.

The structure of the universe is not fully known. Does it have any boundaries? Stephen Hawking believes the universe is boundless yet finite in size. One could keep on moving in one direction and eventually end up in the same place. As an analogy, if you walked in a straight line around Earth, you would eventually return to the same point at which you started.


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Stars & Planets Worksheets

Eyewitness Workbook Stars &amp Planets is an activity-packed exploration of the world of space and astronomy.

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The big bang and our expanding universe - Astronomy

Kruesi, L. “Cosmology: 5 Things You Need to Know.” Astronomy (May 2007): 28. Five questions students often ask, and how modern cosmologists answer them.

Kruesi, L. “How Planck Has Redefined the Universe.” Astronomy (October 2013): 28. Good review of what this space mission has told us about the CMB and the universe.

Lineweaver, C. & Davis, T. “Misconceptions about the Big Bang.” Scientific American (March 2005): 36. Some basic ideas about modern cosmology clarified, using general relativity.

Nadis, S. “Sizing Up Inflation.” Sky & Telescope (November 2005): 32. Nice review of the origin and modern variants on the inflationary idea.

Nadis, S. “How We Could See Another Universe.” Astronomy (June 2009): 24. On modern ideas about multiverses and how such bubbles of space-time might collide.

Nadis, S. “Dark Energy’s New Face: How Exploding Stars Are Changing our View.” Astronomy (July 2012): 45. About our improving understanding of the complexities of type Ia supernovae.

Naze, Y. “The Priest, the Universe, and the Big Bang.” Astronomy (November 2007): 40. On the life and work of Georges Lemaître.

Panek, R. “Going Over to the Dark Side.” Sky & Telescope (February 2009): 22. A history of the observations and theories about dark energy.

Pendrick, D. “Is the Big Bang in Trouble?” Astronomy (April 2009): 48. This sensationally titled article is really more of a quick review of how modern ideas and observations are fleshing out the Big Bang hypothesis (and raising questions.)

Reddy, F. “How the Universe Will End.” Astronomy (September 2014): 38. Brief discussion of local and general future scenarios.

Riess, A. and Turner, M. “The Expanding Universe: From Slowdown to Speedup.” Scientific American (September 2008): 62.

Turner, M. “The Origin of the Universe.” Scientific American (September 2009): 36. An introduction to modern cosmology.

Websites

Cosmology Primer: Caltech Astrophysicist Sean Carroll offers a non-technical site with brief overviews of many key topics in modern cosmology.

Everyday Cosmology: An educational website from the Carnegie Observatories with a timeline of cosmological discovery, background materials, and activities.

How Big Is the Universe?: A clear essay by a noted astronomer Brent Tully summarizes some key ideas in cosmology and introduces the notion of the acceleration of the universe.

Universe 101: WMAP Mission Introduction to the Universe: Concise NASA primer on cosmological ideas from the WMAP mission team.

Cosmic Times Project: James Lochner and Barbara Mattson have compiled a rich resource of twentieth-century cosmology history in the form of news reports on key events, from NASA’s Goddard Space Flight Center.

Videos

The Day We Found the Universe: Distinguished science writer Marcia Bartusiak discusses Hubble’s work and the discovery of the expansion of the cosmos—one of the Observatory Night lectures at the Harvard-Smithsonian Center for Astrophysics (53:46).

Images of the Infant Universe: Lloyd Knox’s public talk on the latest discoveries about the CMB and what they mean for cosmology (1:16:00).

Runaway Universe: Roger Blandford (Stanford Linear Accelerator Center) public lecture on the discovery and meaning of cosmic acceleration and dark energy (1:08:08).


How could an explosive Big Bang be the birth of our universe?

A visualization of tiny energy fluctuations in the early universe. Credit: ESA, Planck Collaboration, CC BY

How can a Big Bang have been the start of the universe, since intense explosions destroy everything? – Tristan S., age 8, Newark, Delaware

Pretend you're a perfectly flat chess piece in a game of chess on a perfectly flat and humongous chessboard. One day you look around and ask: How did I get here? How did the chessboard get here? How did it all start? You pull out your telescope and begin to explore your universe, the chessboard….

What do you find? Your universe, the chessboard, is getting bigger. And over more time, even bigger! The board is expanding in all directions that you can see. There's nothing that seems to be causing this expansion as far as you can tell—it just seems to be the nature of the chessboard.

But wait a minute. If it's getting bigger, and has been getting bigger and bigger, then that means in the past, it must have been smaller and smaller and smaller. At some time, long, long ago, at the very beginning, it must have been so small that it was infinitely small.

Let's work forward from what happened then. At the beginning of your universe, the chessboard was infinitely tiny and then expanded, growing bigger and bigger until the day that you decided to make some observations about the nature of your chess universe. All the stuff in the universe—the little particles that make up you and everything else—started very close together and then spread farther apart as time went on.

Our universe works exactly the same way. When astronomers like me make observations of distant galaxies, we see that they are all moving apart. It seems our universe started very small and has been expanding ever since. In fact, scientists now know that not only is the universe expanding, but the speed at which it's expanding is increasing. This mysterious effect is caused by something physicists call dark energy, though we know very little else about it.

Astronomers also observe something called the Cosmic Microwave Background Radiation. It's a very low level of energy that exists all throughout space. We know from those measurements that our universe is 13.8 billion years old – way, way older than people, and about three times older than the Earth.

If astronomers look back all the way to the event that started our universe, we call that the Big Bang.

Many people hear the name "Big Bang" and think about a giant explosion of stuff, like a bomb going off. But the Big Bang wasn't an explosion that destroyed things. It was the beginning of our universe, the start of both space and time. Rather than an explosion, it was a very rapid expansion, the event that started the universe growing bigger and bigger.

This expansion is different than an explosion, which can be caused by things like chemical reactions or large impacts. Explosions result in energy going from one place to another, and usually a lot of it. Instead, during the Big Bang, energy moved along with space as it expanded, moving around wildly but becoming more spread out over time since space was growing over time.

Back in the chessboard universe, the "Big Bang" would be like the beginning of everything. It's the start of the board getting bigger.

It's important to realize that "before" the Big Bang, there was no space and there was no time. Coming back to the chessboard analogy, you can count the amount of time on the game clock after the start but there is no game time before the start—the clock wasn't running. And, before the game had started, the chessboard universe hadn't existed and there was no chessboard space either. You have to be careful when you say "before" in this context because time didn't even exist until the Big Bang.

You also have wrap your mind around the idea that the universe isn't expanding "into" anything, since as far as we know the Big Bang was the start of both space and time. Confusing, I know!

Astronomers aren't sure what caused the Big Bang. We just look at observations and see that's how the universe did start. We know it was extremely small and got bigger, and we know that kicked off 13.8 billion years ago.

What started our own game of chess? That's one of the deepest questions anyone can ask.

And since curiosity has no age limit—adults, let us know what you're wondering, too. We won't be able to answer every question, but we will do our best.

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Watch the video: ESA Euronews: Ήχοι από τη Μεγάλη Έκρηξη (July 2022).


Comments:

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