Why we have to rethink the age of the Universe

[Leongsam]

Webb Telescope Finds Evidence of Massive Galaxies That Defy Theories of the Early Universe​

The six “universe breakers” appear much larger than what scientists thought was possible at that time

Teresa Nowakowski

Daily Correspondent
February 24, 2023

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Images of the six objects thought to be massive galaxies from the early universe NASA, ESA, CSA, I. Labbe (Swinburne University of Technology). Image processing: G. Brammer (Niels Bohr Institute’s Cosmic Dawn Center at the University of Copenhagen)


Astronomers have identified what appear to be six massive galaxies from the infancy of the universe. The objects are so massive, that if confirmed, they could change how we think of the origins of galaxies.

The findings, published Wednesday in Nature, use data from the James Webb Space Telescope’s infrared-sensing instruments to picture what the universe looked like 13.5 billion years ago—a time when it was just 3 percent of its current age.

Just 500 to 700 million years after the big bang, the potential galaxies were somehow as mature as our 13-billion-year-old Milky Way galaxy is now.

The mass of stars within each of these objects totals to several billion times larger than that of our sun, according to the research. One of them in particular might be as much as 100 billion times our sun’s mass. For comparison, the Milky Way contains a mass of stars equivalent to roughly 60 billion suns.

“You shouldn’t have had time to make things that have as many stars as the Milky Way that fast,” says Erica Nelson, an astrophysicist at the University of Colorado Boulder and a co-author of the study to Lisa Grossman of Science News. “It’s just crazy that these things seem to exist.”

Researchers expected to find only very small, young galaxies this early in the universe’s existence. How these “monsters” were able to “fast-track to maturity” is unknown, says Ivo Labbé, an astrophysicist at Swinburne University of Technology in Australia and the study’s lead researcher, in an email to Marcia Dunn of the Associated Press.

According to most theories of cosmology, galaxies formed from small clouds of stars and dust that gradually increased in size. In the early universe, the story goes, matter came together slowly. But that doesn’t account for the massive size of the newly identified objects.

“The revelation that massive galaxy formation began extremely early in the history of the universe upends what many of us had thought was settled science,” says Joel Leja, an astronomer and astrophysicist at Penn State and a co-author of the study, in a statement. “We’ve been informally calling these objects ‘universe breakers’—and they have been living up to their name so far.”

Emma Chapman, an astrophysicist at the University of Nottingham in England who was not involved in the research, tells the Guardian’s Hannah Devlin that these findings, if confirmed, could change how we conceive of the early universe. “The discovery of such massive galaxies so soon after the big bang suggests that the dark ages may not have been so dark after all, and that the universe may have been awash with star formation far earlier than we thought,” she tells the publication.

Still, it might not be time to rewrite cosmology just yet: The researchers say it’s possible some of the objects could be obscured supermassive black holes, and that what appears to be starlight in the images could actually be gas and dust getting pulled in by their gravity.

“The formation and growth of black holes at these early times is really not well understood,” Emma Curtis-Lake, an astronomer at the University of Hertfordshire in England who was not part of the study, explains to Science News. “There’s not a tension with cosmology there, just new physics to be understood of how they can form and grow, and we just never had the data before.”

To verify their findings, the researchers could take a spectrum image of the objects they’ve pinpointed. This would help reveal how old they are. Galaxies from the early universe appear to us as very “redshifted”—meaning the light they emitted has been stretched out on its long journey to Earth. The higher the redshift value, the more the light has been stretched and the more distant and aged the galaxy is. With spectroscopy, scientists could determine whether their potential galaxies, or “high-redshift candidates,” are as old as they appear, or if they are just “intrinsically reddened galaxies” from a more recent time, says Ethan Siegel, a theoretical astrophysicist who was not involved in the study, to CNET’s Eric Mack.

While Leja agrees that more observations are needed to confirm the findings, he notes in the statement, “Regardless, the amount of mass we discovered means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought. Even if we cut the sample in half, this is still an astounding change.”

 

[Leongsam]

space.com

No, the Big Bang theory is not 'broken.' Here's how we know.​

Paul Sutter

7–9 minutes

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The first publicly released science-quality image from NASA's James Webb Space Telescope, revealed on July 11, 2022, is the deepest infrared view of the universe to date. (Image credit: NASA, ESA, CSA, and STScI)

The James Webb Space Telescope, not even finished with its first full year of observations, has delivered some real stunners. But amid the breathtaking images and unprecedented findings, there was a puzzling claim: that the telescope had detected galaxies in the incredibly young universe. Those galaxies were so massive and appeared so early that they, the headlines claimed, "broke" the Big Bang model of cosmology.

The claim went viral, but as with many things on the internet, it's simply not true.

Now, there's more research to back up the Big Bang. Recently, researchers took a more careful look at the data and determined that the distant galaxies discovered by the James Webb Space Telescope are, indeed, perfectly compatible with our modern understanding of cosmology.

Related: The James Webb Space Telescope never disproved the Big Bang. Here's how that falsehood spread.


Relive the James Webb Space Telescope launch on its anniversary!

The James Webb Space Telescope launched on Dec. 25, 2021. Since then it has delivered some of the most amazing imagery and data on our universe to date. Credit: NASA

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The potential problem with distant galaxies isn't that they exist. In fact, the modern formulation of the Big Bang theory, called ΛCDM cosmology (the Λ stands for dark energy, and CDM is short for "cold dark matter"), predicts galaxies to appear in the very young universe. That's because billions of years ago, there were no galaxies, or even stars, at all. When our universe was much smaller and much denser than it is today, everything was much more uniform, with only tiny density differences appearing here and there randomly.

But over time, those density differences grew, with the slightly denser pockets pulling more material onto them. Over hundreds of millions of years, those pockets formed into the first stars, and eventually grew to become the first galaxies.

In fact, one of the main goals of the Webb telescope was to discover and characterize those first galaxies, so finding galaxies in the incredibly young universe is a point in favor of the Big Bang theory, not against it.

Breaking space news, the latest updates on rocket launches, skywatching events and more!

So what's the conflict, then? The apparent tension came about because of the estimated masses of those galaxies. Several were quite large — well over 10^10 solar masses. That is still much smaller than the Milky Way, but for the early universe, they are quite gigantic.

The researchers who discovered these galaxies estimated that their large masses put them in tension with many models of galactic formation and evolution. At the extreme end, the researchers claimed that it might even be possible for no galaxy formation model within the ΛCDM framework to create such large galaxies so quickly.

James Webb Space Telescope's first deep field image is mind-boggling

The first deep field image captured by the James Webb Space Telescope is of galaxy cluster SMACS 0723. [Biden unveils James Webb Space Telescope's ultradeep view of the universe](https://www.space.com/james-webb-space-telescope-first-photo-biden) Credit: NASA, ESA, CSA, and STScI | mash mix: Space.com Music: Tranquil Dawn by Amber Glow / courtesy of http://www.epidemicsound.com
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A matter of some debate​

But those claims hinged on measuring a precise distance to those galaxies — an incredibly difficult task at these extreme distances. For the record-breaking galaxies that could be tension with cosmological models, the researchers relied on something called a photometric redshift, which fits a rough light spectrum of a galaxy to a model to estimate a distance.

That method is notoriously unreliable, with simple effects — like excess dust surrounding the galaxies — making them appear more distant than they really are.
To accurately judge if the Big Bang is in trouble, a new team of researchers used Webb to identify galaxies with a much more precise and reliable method of determining distance, known as spectroscopic redshift. This technique identifies the spectral lines of known elements emitted by the galaxies and uses them to measure the redshift, and thereby the distance, to the galaxies.

Using this more accurate technique, the team found a sample of four galaxies. All those galaxies were just as distant as the previously identified galaxies, but they had confirmed, reliable distances. However, these galaxies had much smaller masses: around 10^8 and 10^9 solar masses.
So the question then became, does ΛCDM allow for these smaller galaxies to exist at such a young age in the history of the universe, or does the tension remain?

In come the simulations​

Building galaxies is no easy task. While pen-and-paper mathematics can allow cosmologists to chart the overall history and evolution of the cosmos within the ΛCDM model, galaxy formation involves the complex interplay of many kinds of physics: gravity, star formation and supernova explosions, dust distribution, cosmic rays, magnetic fields and more.

Accounting for all these interactions requires the use of supercomputer simulations that take the raw, primal state of the universe as it was billions of years ago and follow the laws of physics to build artificial galaxies. That's the only way to connect what we see in the real world (galaxies) with the fundamental parameters of the ΛCDM model (like the amount of normal and dark matter in the cosmos).

The simulations allowed the researchers to play around with many kinds of models. If no models could generate galaxies of that mass at that age, then ΛCDM would be in trouble.

Thankfully, there were no such problems. The appearance of galaxies with 10^8 solar masses in the early universe was no sweat for ΛCDM, the team explained in their research paper, which has been submitted to The Astrophysical Journal Letters and is available as a preprint via arXiv.

As usual, this isn't the final answer. Astronomers may yet confirm the distance to a very large galaxy in the early universe that may force us to rethink our understanding of galaxy formation, and maybe even the ΛCDM cosmological model. In science, it's always important to keep an open mind. But the exaggerated claims made from the early Webb data aren't enough to worry about yet.

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Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: [email protected].

Paul M. Sutter is an astrophysicist at SUNY Stony Brook and the Flatiron Institute in New York City. Paul received his PhD in Physics from the University of Illinois at Urbana-Champaign in 2011, and spent three years at the Paris Institute of Astrophysics, followed by a research fellowship in Trieste, Italy, His research focuses on many diverse topics, from the emptiest regions of the universe to the earliest moments of the Big Bang to the hunt for the first stars. As an "Agent to the Stars," Paul has passionately engaged the public in science outreach for several years. He is the host of the popular "Ask a Spaceman!" podcast, author of "Your Place in the Universe" and "How to Die in Space" and he frequently appears on TV — including on The Weather Channel, for which he serves as Official Space Specialist.

 

[Truthspeak]

Space is hoax

 

[laksaboy]

This book tells you all you need to know. It tells you about the origins of life, the world and the universe. Its text is freely available online.

Japan (Ja-Pan) is the remnant piece of land of the sunken Pan continent.

 

[Leongsam]

How old is the universe exactly? A new theory suggests that it's been around for twice as long as believed​

by Rajendra Gupta, The Conversation





Galaxy NGC 6822, neighbouring the Milky Way galaxy, being studied to learn more about stars and dust in the early universe. Credit: NASA/James Webb Space Telescope


Early universe observations by the James Webb Space Telescope (JWST) cannot be explained by current cosmological models. These models estimate the universe to be 13.8 billion years in age, based on the big-bang expanding universe concept.


My research proposes a model that determines the universe's age to be 26.7 billion years, which accounts for the JWST's "impossible early galaxy" observations.

Impossible early galaxies refer to the fact that some galaxies dating to the cosmic dawn—500 to 800 million years after the big bang—have disks and bulges similar to those which have passed through a long period of evolution. And smaller in size galaxies are apparently more massive than larger ones, which is quite the opposite of expectation.

Frequency and distance​

This age estimate is derived from the universe's expansion rate by measuring the redshift of spectral lines in the light emitted by distant galaxies. An earlier explanation of the redshift was based on the hypothesis that light loses energy as it travels cosmic distances. This "tired light" explanation was rejected as it could not explain many observations.




The redshift of light is similar to the Doppler effect on sound: noises appear to have higher frequency (pitch) when approaching, and lower when receding. Redshift, a lower light frequency, indicates when an object is receding from us; the larger the galaxy distance, the higher the recessional speed and redshift.

An alternative explanation for the redshift was due to the Doppler effect: Distant galaxies are receding from us at speeds proportional to their distance, indicating that the universe is expanding. The expanding universe model became favored by most astronomers after two astronomers working for Bell Labs, Arno Penzias and Robert Wilson, accidentally discovered cosmic microwave background (CMB) radiation in 1964, which the steady-state model could not satisfactorily explain.

The rate of expansion essentially determines the age of the universe. Until the launch of the Hubble Space Telescope in the 1990s, uncertainty in the expansion rate estimated the universe's age ranging from seven to 20 billion years. Other observations led to the currently accepted value of 13.8 billion years, putting the big-bang model on the cosmology pedestal.



A NASA animation showing how light from distant galaxies is stretched by the expansion of the universe.
Limitations of previous models

Research published last year proposed to resolve the impossible early galaxy problem using the tired light model. However, tired light cannot satisfactorily explain other cosmological observations like supernovae redshifts and uniformity of the cosmic microwave background.

I attempted to combine the standard big-bang model with the tired light model to see how it fits the supernovae data and the JWST data, but it did not fit the latter well. It did, however, increase the universe's age to 19.3 billion years.

Next, I tried creating a hybrid model comprising the tired light and a cosmological model I had developed based on the evolving coupling constants proposed by British physicist Paul Dirac in 1937. This fitted both the data well, but almost doubled the universe's age.

The new model stretches galaxy formation time 10 to 20 fold over the standard model, giving enough time for the formation of well-evolved "impossible" early galaxies as observed.

As with any model, it will need to provide a satisfactory explanation for all those observations that are satisfied by the standard cosmological model.

Mixing models​

The approach of mixing two models to explain new observations is not new. Isaac Newton considered that light propagates as particles in his theory of light, which prevailed until it was replaced by the wave theory of light in the 19th century to explain diffraction patterns observed with monochromatic light.


A galaxy estimated to be as young as 500 million years old, making it one of the youngest galaxies seen. Credit: NASA/ESA Hubble Space Telescope
Albert Einstein resurrected the particle-like nature of light to explain the photoelectric effect—that light has dual characteristics: particle-like in some observations and wave-like in others. It has since become well-established that all particles have such dual characteristics.

Another way of measuring the age of the universe is to estimate the age of stars in globular clusters in our own galaxy—the Milky Way. Globular clusters include up to a million stars, all of which appear to have formed at the same time in the early universe.

Assuming all galaxies and clusters started to form simultaneously, the age of the oldest star in the cluster should provide the age of the universe (less the time when the galaxies began to form). For some stars such as Methuselah, believed to be oldest in the galaxy, astrophysical modeling yields an age greater than the age of the universe determined using the standard model, which is impossible.

Einstein believed that the universe is the same observed from any point at any time—homogeneous, isotropic and timeless. To explain the observed redshift of distant galaxies in such a steady-state universe, which appeared to increase in proportion to their distance (Hubble's law), Swiss astronomer Fritz Zwicky, proposed the tired light theory in 1929.

New information​

While some Hubble Space Telescope observations did point towards the impossible early galaxy problem, it was not until the launch of JWST in December 2021, and the data it provided since mid-2022, that this problem was firmly established.

To defend the standard big-bang model, astronomers have tried to resolve the problem by compressing the timeline for forming massive stars and primordial black holes accreting mass at unphysically high rates.

However, a consensus is developing towards new physics to explain these JWST observations.

 

[Truthspeak]

Globetards loved theory. They cannot differentiate between theory and real science. To them, creating a hypothesis is a form of science

 

[Leongsam]

Globetards loved theory. They cannot differentiate between theory and real science. To them, creating a hypothesis is a form of science

Science is nothing but a never ending series of hypotheses formulated to explain an observation in the physical world.

A hypothesis will be fit for purpose for a while till an observation comes along that defies convention. A new hypothesis is then needed to incorporate this new finding.

EG Newton described gravity as a force and this was universally accepted till Einstein came along and "proved" that gravitational force was actually a curvature in space time.

 

[Truthspeak]

Science is nothing but a never ending series of hypotheses formulated to explain an observation in the physical world.

A hypothesis will be fit for purpose for a while till an observation comes along that defies convention. A new hypothesis is then needed to incorporate this new finding.

Real science is about observations and execution of experiments. Creating hypothesis without any scientific evidence is not science but cult science aka scientism

 

[Truthspeak]

Science is nothing but a never ending series of hypotheses formulated to explain an observation in the physical world.

A hypothesis will be fit for purpose for a while till an observation comes along that defies convention. A new hypothesis is then needed to incorporate this new finding.

EG Newton described gravity as a force and this was universally accepted till Einstein came along and "proved" that gravitational force was actually a curvature in space time.

Objects fall due to its density against the medium surrounding the objects. There is no gravitational force, this is why the sheeple fell for the scam.

 

[Leongsam]

Real science is about observations and execution of experiments. Creating hypothesis without any scientific evidence is not science but cult science aka scentism

Yes science does involve observations and confirming the observations via a series of experiments that are able to reproduce these observations but ultimately a hypothesis has to be put forward to explain what is being observed and equations formulated that fit the observations and are able to predict an outcome given a set of parameters.

ALL scientific equations are hypotheses but they serve us well till something comes along to break things. The science is never settled.

 

[Truthspeak]

Yes science does involve observations and confirming the observations via a series of experiments that are able to reproduce these observations but ultimately a hypothesis has to be put forward to explain what is being observed and equations formulated that fit the observations and are able to predict an outcome given a set of parameters.

ALL scientific equations are hypotheses but they serve us well till something comes along to break things. The science is never settled.

If a hypothesis cannot be concluded using scientific methods, then that is not a science to begin with. That is an opinion, assumption or agenda used to indoctrinate the masses

 

[Leongsam]

If a hypothesis cannot be concluded using scientific methods, then that is not a science to begin with. That is an opinion, assumption and agenda to indoctrinate the masses

There should never be conclusions in science. This is what has happened with the climate change baloney which claims that the science is "settled" so that taxes can be imposed and riches collected.

Science is nothing more than an ongoing journey towards a goal of greater understanding. There is no such thing as a complete understanding. Only our creator can claim that.

 

[Truthspeak]

There should never be conclusions in science. This is what has happened with the climate change baloney which claims that the science is "settled" so that taxes can be imposed and riches collected.

Science is nothing more than an ongoing journey towards a goal of greater understanding. There is no such thing as a complete understanding. Only our creator can claim that.

There is a conclusion to science. For example, no matter how long you have observed, the sun will always rise from the east. For water,

 

[Leongsam]

There is a conclusion to science. For example, no matter how long you have observed, the sun will always rise from the east. For water,

View attachment 201625

These are layman observations based on the limited observational ability of the human eye. However at microscopic and quantum level all these observations are no longer valid. Molecular and sub atomic forces come into play.

 

[Truthspeak]

These are layman observations based on the limited observational ability of the human eye. However at microscopic and quantum level all these observations are no longer valid. Molecular and sub atomic forces come into play.

View attachment 201626

If one don’t understand the physics of large mass of water, they can refer to your example and get themselves misled with their science.

 

[Leongsam]

If one don’t understand the physics of large mass of water, they can refer to your example and get themselves misled with their science.

View attachment 201627

When you add an extra dimension the earth is indeed flat. In fact the whole universe is flat.


https://www.space.com/34928-the-universe-is-flat-now-what.html

The Universe Is Flat — Now What?​

News
By Paul Sutter
published December 8, 2016

The Hubble Space Telescope accumulated approximately 555 hours of exposure time to capture this Hubble eXtreme Deep Field image. The area shown represents a seemingly empty patch of sky about the width of a toothpick when held at arm's length. The picture contains only two foreground stars (indicated by surrounding spikes). Every other object is a galaxy. The most distant galaxies' light is reddened by the expansion of the universe. We're seeing light that left them 13.2 billion years ago. (Image credit: NASA)

Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI Science Center. Sutter is also host of Ask a Spaceman, RealSpace, and COSI Science Now.
Spoiler alert: The universe is flat. But there's a lot of subtlety packed into that innocent-looking statement. What does it mean for a 3D object to be "flat"? How do we measure the shape of the universe anyway? Since the universe is flat, is that…it? Is there anything else interesting to say?

Oh yes, there is.

Walk the line​

First, we need to define what we mean by flat. The screen you're reading this on is obviously flat (I hope), and you know that the Earth is curved (I hope). But how can we quantify that mathematically? Such an exercise might be useful if we want to go around measuring the shape of the whole entire universe. [The History & Structure of the Universe (Infographic)]
One answer lies in parallel lines. If you start drawing two parallel lines on your paper and let them continue on, they'll stay perfectly parallel forever (or at least until you run out of paper). That was essentially the definition of a parallel line for a couple thousand years, so we should be good.
Let's repeat the exercise on the surface of the Earth. Start at the equator and draw a couple parallel lines, each pointing directly north. As the lines continue, they never turn left or right but still end up intersecting at the North Pole. The curvature of the Earth itself caused these initially parallel lines to end up not-so-parallel. Ergo, the Earth is curved.
The opposite of the Earth's curved shape is a saddle: on that surface, lines that start out parallel end up spreading apart from each other (in swanky mathematical circles this is known as "ultraparallel"). [I explore the possible shapes of the universe in this video.]

Get the Space.com Newsletter​

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The shape of the universe depends on its density. If the density is more than the critical density, the universe is closed and curves like a sphere; if less, it will curve like a saddle. But if the actual density of the universe is equal to the critical density, as scientists think it is, then it will extend forever like a flat piece of paper. (Image credit: NASA/WMAP Science team.)
So there you have it: You can measure the "flatness" of a structure just by watching how parallel lines behave. In our 3D universe, we could watch beams of light: If, say, two lasers started out perfectly parallel, then their long-term behavior would tell us important things.

Flat as a (big) pancake​

Remember that measuring the shape of the universe is a question for cosmology, the study of the entire universe. And in cosmology, nobody cares about you. Or me. Or solar systems. Or black holes. Or galaxies. In cosmology we care about the universe only at the very largest scales; small-scale bumps and wiggles are not important for this question.

The universe has all sorts of deformations in space-time where it varies from the perfectly flat. Any place where there's mass or energy, there's a corresponding bending of space-time — that's General Relativity 101. So a couple light beams would naturally collide inside a wandering black hole, or bend along weird angles after encountering a galaxy or two.

Click here for more Space.com videos...




But average all those small-scale effects out and look at the big picture. When we examine very old light — say, the cosmic microwave background — that has been traveling the universe for more than 13.8 billion years, we get a true sense of the universe's shape. And the answer, as far as we can tell, to within an incredibly small margin of uncertainty, is that the universe is flat.

There is no spoon​

Well, that settles that. But this article isn't over yet, which means there's more to the story.

Have you ever asked yourself if there's a difference between a cylinder and a sphere? More than likely not, but it's never too late to try new things.

Take out your piece of paper with two parallel lines on it. Go ahead, dig it out of the trash. Wrap one end around to meet the other, making a cylinder. Carefully observe the parallel lines — they remain parallel, don't they? That's because cylinders are flat.

You heard it here first: Cylinders are flat.

There's an important distinction between geometry, the behavior of parallel lines, and topology, the way a space can get all twisted up. While the geometry of the universe is very well measured (again, it's flat), the topology is not. And here's a bonus fact: not only can we not determine the topology of the universe from observations, but there are also no laws of physics that predict or restrict the topology.

With your 2D piece of paper, you can connect the ends a few different ways. Connect one of the dimensions normally and you have a cylinder. Flip one edge over before connecting and you've made a Mobius strip. Connect two dimensions, the top to the bottom and one side to the other, and you have a torus (aka a donut).

In our 3D universe, there are lots of options — 18 known ones, to be precise. Mobius strips, Klein bottles and Hantzsche-Wendt space manifolds are all non-trivial topologies that share something in common: if you travel far enough in one direction, you come back to where you started. In the case of flipped dimensions, when you come back to your starting point, you'll find yourself upside down without having tried to do so at all. [Watch: Explaining the Shape of the Universe.]

Of course we've looked to see if our universe is connected like this; we don't see any copies of galaxies, and we don't see the cosmic microwave background intersecting itself. If the universe is pretzeled-up, it's on scales far, far larger than what we can observe.

So don't get too excited by possibility of living in a real-life version of the "Asteroids" game — which, as you now know, is played on the surface of a donut.

Learn more by listening to the episode "What's the shape of the universe?" on the Ask A Spaceman podcast, available on iTunes and on the Web at http://www.askaspaceman.com. Thanks to Greg S. and Michael W. for the questions that led to this piece! Ask your own question on Twitter using #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter.

 

[Truthspeak]

When you add an extra dimension the earth is indeed flat. In fact the whole universe is flat.


https://www.space.com/34928-the-universe-is-flat-now-what.html

The Universe Is Flat — Now What?​

News
By Paul Sutter
published December 8, 2016

The Hubble Space Telescope accumulated approximately 555 hours of exposure time to capture this Hubble eXtreme Deep Field image. The area shown represents a seemingly empty patch of sky about the width of a toothpick when held at arm's length. The picture contains only two foreground stars (indicated by surrounding spikes). Every other object is a galaxy. The most distant galaxies' light is reddened by the expansion of the universe. We're seeing light that left them 13.2 billion years ago. (Image credit: NASA)

Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI Science Center. Sutter is also host of Ask a Spaceman, RealSpace, and COSI Science Now.
Spoiler alert: The universe is flat. But there's a lot of subtlety packed into that innocent-looking statement. What does it mean for a 3D object to be "flat"? How do we measure the shape of the universe anyway? Since the universe is flat, is that…it? Is there anything else interesting to say?

Oh yes, there is.

Walk the line​

First, we need to define what we mean by flat. The screen you're reading this on is obviously flat (I hope), and you know that the Earth is curved (I hope). But how can we quantify that mathematically? Such an exercise might be useful if we want to go around measuring the shape of the whole entire universe. [The History & Structure of the Universe (Infographic)]
One answer lies in parallel lines. If you start drawing two parallel lines on your paper and let them continue on, they'll stay perfectly parallel forever (or at least until you run out of paper). That was essentially the definition of a parallel line for a couple thousand years, so we should be good.
Let's repeat the exercise on the surface of the Earth. Start at the equator and draw a couple parallel lines, each pointing directly north. As the lines continue, they never turn left or right but still end up intersecting at the North Pole. The curvature of the Earth itself caused these initially parallel lines to end up not-so-parallel. Ergo, the Earth is curved.
The opposite of the Earth's curved shape is a saddle: on that surface, lines that start out parallel end up spreading apart from each other (in swanky mathematical circles this is known as "ultraparallel"). [I explore the possible shapes of the universe in this video.]

Get the Space.com Newsletter​

Breaking space news, the latest updates on rocket launches, skywatching events and more!
Contact me with news and offers from other Future brandsReceive email from us on behalf of our trusted partners or sponsors
By submitting your information you agree to the Terms & Conditions and Privacy Policy and are aged 16 or over.

The shape of the universe depends on its density. If the density is more than the critical density, the universe is closed and curves like a sphere; if less, it will curve like a saddle. But if the actual density of the universe is equal to the critical density, as scientists think it is, then it will extend forever like a flat piece of paper. (Image credit: NASA/WMAP Science team.)
So there you have it: You can measure the "flatness" of a structure just by watching how parallel lines behave. In our 3D universe, we could watch beams of light: If, say, two lasers started out perfectly parallel, then their long-term behavior would tell us important things.

Flat as a (big) pancake​

Remember that measuring the shape of the universe is a question for cosmology, the study of the entire universe. And in cosmology, nobody cares about you. Or me. Or solar systems. Or black holes. Or galaxies. In cosmology we care about the universe only at the very largest scales; small-scale bumps and wiggles are not important for this question.

The universe has all sorts of deformations in space-time where it varies from the perfectly flat. Any place where there's mass or energy, there's a corresponding bending of space-time — that's General Relativity 101. So a couple light beams would naturally collide inside a wandering black hole, or bend along weird angles after encountering a galaxy or two.

Click here for more Space.com videos...




But average all those small-scale effects out and look at the big picture. When we examine very old light — say, the cosmic microwave background — that has been traveling the universe for more than 13.8 billion years, we get a true sense of the universe's shape. And the answer, as far as we can tell, to within an incredibly small margin of uncertainty, is that the universe is flat.

There is no spoon​

Well, that settles that. But this article isn't over yet, which means there's more to the story.

Have you ever asked yourself if there's a difference between a cylinder and a sphere? More than likely not, but it's never too late to try new things.

Take out your piece of paper with two parallel lines on it. Go ahead, dig it out of the trash. Wrap one end around to meet the other, making a cylinder. Carefully observe the parallel lines — they remain parallel, don't they? That's because cylinders are flat.

You heard it here first: Cylinders are flat.

There's an important distinction between geometry, the behavior of parallel lines, and topology, the way a space can get all twisted up. While the geometry of the universe is very well measured (again, it's flat), the topology is not. And here's a bonus fact: not only can we not determine the topology of the universe from observations, but there are also no laws of physics that predict or restrict the topology.

With your 2D piece of paper, you can connect the ends a few different ways. Connect one of the dimensions normally and you have a cylinder. Flip one edge over before connecting and you've made a Mobius strip. Connect two dimensions, the top to the bottom and one side to the other, and you have a torus (aka a donut).

In our 3D universe, there are lots of options — 18 known ones, to be precise. Mobius strips, Klein bottles and Hantzsche-Wendt space manifolds are all non-trivial topologies that share something in common: if you travel far enough in one direction, you come back to where you started. In the case of flipped dimensions, when you come back to your starting point, you'll find yourself upside down without having tried to do so at all. [Watch: Explaining the Shape of the Universe.]

Of course we've looked to see if our universe is connected like this; we don't see any copies of galaxies, and we don't see the cosmic microwave background intersecting itself. If the universe is pretzeled-up, it's on scales far, far larger than what we can observe.

So don't get too excited by possibility of living in a real-life version of the "Asteroids" game — which, as you now know, is played on the surface of a donut.

Learn more by listening to the episode "What's the shape of the universe?" on the Ask A Spaceman podcast, available on iTunes and on the Web at http://www.askaspaceman.com. Thanks to Greg S. and Michael W. for the questions that led to this piece! Ask your own question on Twitter using #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter.

This happens when sheeple no longer using their eyes to discern information. They rely on an authority for information and get themselves brainwashed with the information provided. They don’t even demand for any scientific evidence and accountability from the authorities anymore

 

[Truthspeak]

Covid-19 is an example of sheeple no longer using their eyes to discern information. They thought that the information provided by the government is science lol

 

[Leongsam]

This happens when sheeple no longer using their eyes to discern information. They rely on an authority for information and get themselves brainwashed with the information provided. They don’t even demand for any scientific evidence and accountability from the authorities anymore

The human eye is one of the least reliable devices on earth. Your eyes lie to you daily.

 

[Truthspeak]

The human eye is one of the least reliable devices on earth. Your eyes lie to you daily.

If you would like to think human eye is one of the least reliable devices on earth, you should not even bring up about the creator.