## The 18 biggest unsolved mysteries in physics

Profound physics.

In 1900, the British physicist Lord Kelvin is said to have pronounced: "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement." Within three decades, quantum mechanics and Einstein's theory of relativity had revolutionized the field. Today, no physicist would dare assert that our physical knowledge of the universe is near completion. To the contrary, each new discovery seems to unlock a Pandora's box of even bigger, even deeper physics questions. These are our picks for the most profound open questions of all.

Related: Check out the 14 biggest historical mysteries that may never be solved.

Inside you’ll learn about parallel universes, why time seems to move in one direction only, and why we don’t understand chaos.

## What is dark energy?

Next Up: Dark matter (scroll up to see the "Next" button)

## What is dark matter?

## Why is there an arrow of time?

## Are there parallel universes?

Next Up: Matter vs. Antimatter

## Why is there more matter than antimatter?

## What is the fate of the universe?

Next Up: An even stranger concept

## How do measurements collapse quantum wavefunctions?

## Is string theory correct?

Finally: We end with chaos . . .

## Is there order in chaos?

## Do the universe's forces merge into one?

## What happens inside a black hole?

## Do naked singularities exist?

## Violating charge-parity symmetry

## When sound waves make light

## What lies beyond the Standard Model?

## Fundamental constants

## What the heck is gravity, anyway?

## Do we live in a false vacuum?

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Why do magnets have north and south poles?

Dark matter's secret identity could be hiding in distorted 'Einstein rings'

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## 10 mysteries that physics can't answer... yet

## What came before the big bang?

## How does a bicycle stay upright?

## The 7 Biggest Unanswered Questions in Physics

## 1. What is matter made of?

## 2. Why is gravity so weird?

## 3. Why does time seem to flow only in one direction?

## Related First-of-Its-Kind DNA Video Raises Big Question About Molecule of Heredity

4. where did all the antimatter go.

## 5. What happens in the gray zone between solid and liquid?

So a better understanding of this “gray zone” might have important practical applications.

## 6. Can we find a unified theory of physics?

## Related Walls Won't Save Our Cities From Rising Seas. Here's What Will

7. how did life evolve from nonliving matter.

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## Why students still can't solve physics problems after solving over 2000 problems

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Taejin Byun , Gyoungho Lee; Why students still can't solve physics problems after solving over 2000 problems. American Journal of Physics 1 September 2014; 82 (9): 906–913. https://doi.org/10.1119/1.4881606

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This study investigates the belief that solving a large number of physics problems helps students better learn physics. We investigated the number of problems solved, student confidence in solving these problems, academic achievement, and the level of conceptual understanding of 49 science high school students enrolled in upper-level physics classes from Spring 2010 to Summer 2011. The participants solved an average of 2200 physics problems before entering high school. Despite having solved so many problems, no statistically significant correlation was found between the number of problems solved and academic achievement on either a mid-term or physics competition examination. In addition, no significant correlation was found between the number of physics problems solved and performance on the Force Concept Inventory (FCI). Lastly, four students were selected from the 49 participants with varying levels of experience and FCI scores for a case study. We determined that their problem solving and learning strategies was more influential in their success than the number of problems they had solved.

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## 10 Unsolved Problems In Astrophysics That Are Way Too Interesting.

Admin and Founder of ‘The Secrets Of The Universe’ and former intern at Indian Institute of Astrophysics, Bangalore, I am a science student pursuing a Master’s in Physics from India . I love to study and write about Stellar Astrophysics, Relativity & Quantum Mechanics.

Though it has been more than 200 years since astrophysics formally began, what we know is just a drop. The vast ocean of knowledge lays undiscovered before us. I thought of ending this series by writing about some of the major unsolved problems in astrophysics.

Exactly two months ago, we started our journey of exploring the cosmos. We started with the most basic question: What is Astrophysics? We learned some of the basic tools used in this subject: the EM Spectrum , distances in astronomy , the concept of magnitude , the classification of stars , types of redshifts , basics of telescopes , the Hertzsprung Russell Diagram, and so on. Then we studied the structure of Sun , nuclear reactions in stars , stellar evolution , the formation of neutron stars and black holes, types of black holes , quasars , galaxies , nebulae , dark matter , gravitational waves , radio astronomy , and the CMB radiation. We shall now conclude this series by discussing the top 10 unsolved problems in Astrophysics.

Read all the articles of Basics of Astrophysics series here

## Unsolved Problems In Astrophysics

10. tabby’s star.

Tabby’ star, formally known as KIC 8462852, is an F type main-sequence star in the constellation of Cygnus. What brought Tabby’s star in limelight is its anomalous dimming. One of the graphs that shows the maximum dimming of around 22% is given below.

Several hypotheses have been put forward to explain these fluctuations. The first one says that the star is surrounded by an uneven ring of dust. According to NASA, researchers found less dimming in the infrared light from the star than in its ultraviolet light. Any object larger than dust particles would dim all wavelengths of light equally when passing in front of Tabby’s Star. The second hypothesis says that Tabby’s star is surrounded by a cloud of disintegrating comets orbiting the star elliptically. But, the fact that a cloud of a comet can cause dimming up to 22% has cast doubt on this theory.

Another interesting hypothesis says that the dimming might be a result of an alien megastructure. That alien megastructure could be the Dyson swarm, built by civilizations to intercept their star’s light for their energy needs. However, the likelihood of extraterrestrial intelligence being the cause of the dimming is very low

## 9. Origin of Magnetar Magnetic Field

Magnetars are neutron stars with a tremendous magnetic field. The magnetic field of a typic magnetar lies between 1-100 billion Tesla. To bring it to perspective, the maximum magnetic field that can be generated under special laboratory conditions is just a few hundred Tesla. Just like the neutron stars, they are about 20 Km wide and have a mass of 2-3 times that of Sun. This implies they are quite dense. A tablespoon of its material will weigh 100 million tonnes.

The origin of such a strong magnetic field is hypothesized to be a magnetohydrodynamic process in the turbulent, extremely dense conducting fluid that exists before the neutron star settles into its equilibrium position. The magnetic field of a magnetar would be lethal even at a distance of 1000 km due to the strong magnetic field distorting the electron clouds of the subject’s constituent atoms, rendering the chemistry of life impossible. At a distance of halfway from Earth to the moon, a magnetar could strip information from the magnetic stripes of all credit cards on Earth. As of 2010, they are the most powerful magnetic objects detected throughout the universe.

Popular in series:

- How do neutron stars and black holes form?
- The most powerful object in the universe
- Gravitational waves and their importance

## 8. Fast Radio Bursts

Fast Radio Bursts (FRBs) are unresolved (point source-like), broadband (spanning a large range of radio frequencies), millisecond flashes found in parts of the sky. The physical phenomenon that causes these bursts is still a mystery. Possible sources of FRBs are neutron stars, black holes, or extraterrestrial intelligence.

Although the exact origin and cause is uncertain, most are believed to be extragalactic. The first Milky Way FRB was detected in April 2020. The origin of FRBs is still one of the most intriguing unsolved problems in astrophysics.

## 7. Ultra-High Energy Cosmic Rays

The Ultra-High Energy Cosmic Rays (UHECR) are the cosmic rays with unimaginably high energy: greater than exa electron volt (10^18 eV). The Oh My God particle by the University of Utah’s Fly’s Eye experiment on the evening of 15 October 1991 over Dugway Proving Ground, Utah was a shock to astrophysicists.

They estimated its energy to be approximately 3.2×10^20 eV (50 J) —in other words, an atomic nucleus with kinetic energy equal to that of a baseball (5 ounces or 142 grams) traveling at about 100 kilometers per hour (60 mph). The origin of such particles is still a hypothesis. It is one of the major unsolved problems in astrophysics.

## Recommended Book To Start Astrophysics

6. the solar cycle.

The solar cycle is a repeated cycle of solar fluctuations that has a period of 11 years. Every 11 years, the magnetic field of the Sun flips completely. This means that the Sun’s north and south poles switch places. The solar activity is also influenced by this cycle. The beginning of the solar cycle is the solar minimum, with minimum sunspots. Then, in the middle of the cycle, the solar activity reaches its maximum and the number of sunspots also increases.

Giant eruptions on the Sun, such as solar flares and coronal mass ejections, also increase during the solar cycle. These eruptions send powerful bursts of energy and material into space. Understanding the solar cycle is still a great mystery for scientists.

## 5. The Corona Mystery

Another unsolved problem in solar physics is the corona mystery. The corona is the outermost part of the solar atmosphere. It can be seen during a total solar eclipse. The problem is that the corona has a temperature of about a million K while the surface of the Sun, the photosphere, is at about 5,900 K. How can the heat flow from cold to the hot body? How can the most basic law of thermodynamics break down? Is there any other mechanism that is taking place in the corona? If yes, then what is it? Is it the Alfven Waves?

## 4. The Lithium Problem

The lithium problem is an astrophysical problem on the abundance of Li-7 isotope. Minutes after the big bang, the first elements formed. These included hydrogen, helium, lithium, and trace amounts of other elements. The observed composition of the universe is consistent with the big bang model for hydrogen and helium. However, there is a discrepancy when it comes to lithium. The most widely accepted models of the Big Bang suggest that three times as much primordial lithium should exist.

Several solutions have been hypothesized to solve the missing lithium problem. There might be a need for more accurate determination of the abundance of lithium in the universe. The astrophysical solution says that there is an error in calculation. Another possible way to find the remaining lithium is to make corrections in nuclear physics. Incorrect or missing reactions could give rise to the lithium problem.

## 3. Hawking Radiation

The Hawking radiation is electromagnetic radiation that is predicted to be released by black holes due to quantum events near the event horizon.

It is important to recall that for all discovered and localized black holes, this effect is too small to be measured under experimentally achievable conditions. Because of that, Hawking radiation has not been detected yet. In the meantime, physicists are building and analyzing analogous systems.

In September 2010, it was thought that a laboratory-created body, simulating a white hole’s event horizon radiated an optical analog to Hawking radiation, although to this date no official confirmation of the accuracy of this experiment exists. One of the latest predictions also links sonic black holes (for which sound perturbations are analogous to light in a gravitational black hole) to a form of perfect fluid flow that could simulate Hawking radiation. Read about Hawking radiation in our detailed article here.

You may also like:

- How to become an astrophysicist?
- Top 10 astrophysicists in history
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While it is not yet known how and when will Hawking radiation be detected, scientists are diligently working towards this purpose. What happens after such radiation is discovered is also unknown, but one can only hope that it will open a new era when it comes to understanding black holes.

## 2. Galaxy Rotation Curve And Dark Matter

As we studied in detail in the article on the dark universe , A galactic rotation curve is the plot of the orbital rotational velocity of stars versus their distance from the center. Consider the solar system. Mercury orbits the Sun in 88 days while for Neptune, it takes about 165 years. Also, the orbital velocity of planets decreases as we go from Mercury to Neptune. However, this is not true for disk galaxies. Stars revolve around their galaxy’s center at equal or increasing speed over a large range of distances.

This discrepancy has two implications. Either Newton’s laws of classical mechanics aren’t universal or there is an additional matter in the galaxy that isn’t visible to us. This invisible matter is known as dark matter. The discrepancy in the galaxy rotation curves is one of the first evidence of dark matter.

## How was the series?

1. black holes.

One of the most important unsolved problems in Astrophysics is black holes. Black holes first appeared in the solutions of the equations of general relativity. Though a lot of research is taking place in this field, the question is: Do the mathematical black holes predicted by General Relativity really exist, or are they the eternally collapsing objects?

Also watch: What is string theory?

The scientific community is divided into two sects: one which says that the black holes observed are the ones that are predicted by GTR, having a singularity while others say that they aren’t the mathematical black holes but are eternally collapsing objects. There are many observed facts that the former cannot explain. One of them is the strength of the magnetic field. How can black holes produce such a strong magnetic field when the only source is the particles of the accretion disk. You can find peer-reviewed research papers on the Eternally Collapsing Objects here .

The model of eternally collapsing objects instead of black holes accounts for many observed facts and is thought to be a better model. But still far away from being accepted worldwide.

These were some of the major unsolved problems in astrophysics.

## Author’s Message

This concludes the Basics of Astrophysics series. These 30 articles were one of the most challenging projects taken up by us. It took us a lot of time to design, write, and share this series with you. Squeezing such a vast topic into just 30 easy to understand articles was difficult. I am glad that the series received a great response worldwide. One of the basic purpose to bring such a series was to tell the importance of physics in this field. I also wanted to shed light on the vastness of the subject. People think that Astrophysics is all about the glamorous topics, the ones popular in science fiction. But no, there is much more and these 30 articles are proof.

Though the series is ending, the journey will continue. Our team will be back with another educational series like this one. Keep visiting us.

Hello Rishab, this article was very interesting and informative. And I also came to know about many windows that are open in the research field. I really enjoyed reading your article on basics of astrophysics. thank you .

Dear Rishab, I have thoroughly enjoyed reading your articles. A big compliment for the effort you have put into it, especially the Q&A videos provided a lot of extra information. I am a complete amateur to this field of science (also 63 years old, studied shipbuilding when I was younger and I am not going to take up physics/mathematics again to become an astrophysicist) but it was a nice journey to freshen up or learn about new topics you and your co-writers presented in these articles. All I have to do now is to dive deeper into the theory by exploring all the pingbacks that you linked to in the comment sections. A lot more interesting reading material lies ahead of me, thanks again!

[…] 10 unsolved problems in Astrophysics […]

[…] Read Now […]

[…] 10 unsolved problems in astrophysics […]

I am a curious student right now studying in 12th science. I am very interested in Astronomy (i.e. everything related to space for me?) from always. I am reading all your articles and always excited to know more. Thank you for all this.?

This is really a good article. I’m a student from Kolkata, India pursuing my B.Sc. physics from Calcutta University and dream of doing cosmology in the future I like your blog very much. And I’m also trying have a blog of my own here https://naturescience234.blogspot.com

i read this and i am shocked how they dont even introduce us to basic astrophysics in high school

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## How to Solve Any Physics Problem

Last Updated: December 20, 2022

wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 23 people, some anonymous, worked to edit and improve it over time. This article has been viewed 304,259 times. Learn more...

Baffled as to where to begin with a physics problem? There is a very simply and logical flow process to solving any physics problem.

## Community Q&A

## Video . By using this service, some information may be shared with YouTube.

- Many people report that if they leave a problem for a while and come back to it later, they find they have a new perspective on it and can sometimes see an easy way to the answer that they did not notice before. ⧼thumbs_response⧽ Helpful 247 Not Helpful 46
- Try to understand the problem first. ⧼thumbs_response⧽ Helpful 185 Not Helpful 49
- Remember, the physics part of the problem is figuring out what you are solving for, drawing the diagram, and remembering the formulae. The rest is just use of algebra, trigonometry, and/or calculus, depending on the difficulty of your course. ⧼thumbs_response⧽ Helpful 113 Not Helpful 34

- Physics is not easy to grasp for many people, so do not get bent out of shape over a problem. ⧼thumbs_response⧽ Helpful 98 Not Helpful 24
- If an instructor tells you to draw a free body diagram, be sure that that is exactly what you draw. ⧼thumbs_response⧽ Helpful 87 Not Helpful 24

## Things You'll Need

- A Writing Utensil (preferably a pencil or erasable pen of sorts)
- Calculator with all the functions you need for your exam
- An understanding of the equations needed to solve the problems. Or a list of them will suffice if you are just trying to get through the course alive.

## You Might Also Like

- ↑ https://iopscience.iop.org/article/10.1088/1361-6404/aa9038
- ↑ https://physics.wvu.edu/files/d/ce78505d-1426-4d68-8bb2-128d8aac6b1b/expertapproachtosolvingphysicsproblems.pdf
- ↑ https://www2.southeastern.edu/Academics/Faculty/rallain/scaleup/problem_solving.html
- ↑ https://www.brighthubeducation.com/science-homework-help/42596-tips-to-choosing-the-correct-physics-formula/

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## Physics Problems with Solutions

## Physics Problems with Solutions and Tutorials

Physics problems with solutions and tutorials with full explanations are included. More emphasis on the topics of physics included in the SAT physics subject with hundreds of problems with detailed solutions. Physics concepts are clearly discussed and highlighted. Real life applications are also included as they show how these concepts in physics are used in engineering systems for example. HTML 5 apps designed for desktop, iPad and other tablets, are also included to explore interactively physics concepts. These apps "get" you closer to the physics concept you wish to understand.

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## 10 Hard Math Problems That Continue to Stump Even the Brightest Minds

Maybe you’ll have better luck.

For now, you can take a crack at the hardest math problems known to man, woman, and machine. ✅ More from Popular Mechanics :

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There is a function, called the Riemann zeta function, written in the image above.

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## What does is really mean to say that a 3-body problem is not solvable? [duplicate]

- 1 $\begingroup$ Related: Why does the three-body problem have no solution? More on 3-body problem . $\endgroup$ – Qmechanic ♦ Apr 12, 2022 at 14:13
- 3 $\begingroup$ TLDR, "solve" means, "find a closed form expression for the motion of the bodies." A numerical simulation of their motion doesn't count as a "solution." $\endgroup$ – Solomon Slow Apr 12, 2022 at 15:06

## 4 Answers 4

See Why does the three-body problem have no solution?

The three-body problem is a special case of the n-body problem. Unlike two-body problems, no general closed-form solution exists,[1] as the resulting dynamical system is chaotic for most initial conditions, and numerical methods are generally required.

- 4 $\begingroup$ Now, whether you get the correct solution is another question, particularly since numerical methods have limited precision, and slightly different initial conditions lead to that chaos thing... $\endgroup$ – Jon Custer Apr 12, 2022 at 13:43
- $\begingroup$ So the point is that numerical solutions exist, but no one has yet found an analytical solution? $\endgroup$ – Solidification Apr 12, 2022 at 13:45
- $\begingroup$ @JonCuster Good point! $\endgroup$ – Andrew Apr 12, 2022 at 13:47
- 1 $\begingroup$ @Solidification I would think that the "yet" is in the realm of "impossible". $\endgroup$ – anna v Apr 12, 2022 at 13:49
- $\begingroup$ @Solidification Basically. Although (a) as Jon points out, the numerical solutions are very hard, and (b) it's not just that no one has found analytical solutions yet, it's that the solutions are known to have properties (chaos) that are extremely hard to represent analytically (like annav says, 'extremely hard' here probably means impossible to write a closed form expression in terms of simple functions). $\endgroup$ – Andrew Apr 12, 2022 at 13:49

There has been always discussion about what is called solvable in the community.

- $\begingroup$ If I'm not wrong, the equation $\ddot{x}=-\sin x$ is exactly solvable (in terms of elliptic integrals). $\endgroup$ – Solidification Apr 12, 2022 at 14:28
- 1 $\begingroup$ @Solidification afaik, special functions like those are not generally considered "closed form", wikipedia actually has a nice table of what's included in each category en.wikipedia.org/wiki/… $\endgroup$ – llama Apr 13, 2022 at 5:01

## It is Solvable...

Why is it not possible to solve the differential equations on a computer with adequate initial conditions?

## ...In the Integers

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## Not the answer you're looking for? Browse other questions tagged newtonian-mechanics newtonian-gravity computational-physics differential-equations three-body-problem or ask your own question .

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## Tips, tricks, lessons, and tutoring to help reduce test anxiety and move to the top of the class.

## 10 Math Equations That Have Never Been Solved

By Kathleen Cantor, 10 Sep 2020

## 1. The Riemann Hypothesis

Equation: σ (n) ≤ Hn +ln (Hn)eHn

- Where n is a positive integer
- Hn is the n-th harmonic number
- σ(n) is the sum of the positive integers divisible by n

## 2. The Collatz Conjecture

## 3. The Erdős-Strauss Conjecture

## 4. Equation Four

Equation: Use 2(2∧127)-1 – 1 to prove or disprove if it’s a prime number or not?

Looks pretty straight forward, does it? Here is a little context on the problem.

## 5. Goldbach's Conjecture

Equation: Prove that x + y = n

## 6. Equation Six

Equation: Prove that (K)n = JK1N(q)JO1N(q)

- Where O = unknot (we are dealing with knot theory )
- (K)n = Kashaev's invariant of K for any K or knot
- JK1N(q) of K is equal to N- colored Jones polynomial
- We also have the volume of conjecture as (EQ3)
- Here vol(K) = hyperbolic volume

## 7. The Whitehead Conjecture

## 8. Equation Eight

## 9. The Euler-Mascheroni Constant

Equation: y=limn→∞(∑m=1n1m−log(n))

## 10. Equation Ten

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Posted in Mathematics category - 10 Sep 2020 [ Permalink ]

## 11 Comments on “10 Math Equations That Have Never Been Solved”

Maybe only, if you know meaning of this three symbols up writen and connected together.

8.539728478 is the answer to number 10

8.539728478 is the answer to number 10 or 8.539734221

The sum of π and e is equal to π + e = 3.14159 + 2.71828 = 5.85987.

In conclusion, the sum of π and e is equal to 5.85987, which is an algebraic number.

n = 5 3n + 1 = 3(5) + 1 = 16 n = 16/2 = 8 n = 8/2 = 4 n = 4/2 = 2 n = 2/2 = 1 n = 1/2 = 0.5

If n is equal to 4, the sequence of values will be: n = 4 3n + 1 = 3(4) + 1 = 13 n = 13/2 = 6.5

n = 6 3n + 1 = 3(6) + 1 = 19 n = 19/2 = 9.5

If n is equal to 4, the sequence of values will be:

n = 4 3n + 1 = 3(4) + 1 = 13 n = 13/2 = 6.5

n = 9 3n + 1 = 3(9) + 1 = 28 n = 28/2 = 14 n = 14/2 = 7 n = 7/2 = 3.5

n = 3 3n + 1 = 3(3) + 1 = 10 n = 10/2 = 5 n = 5/2 = 2.5

n = 2 3n + 1 = 3(2) + 1 = 7 n = 7/2 = 3.5

As we can see, the sequence of values becomes repetitive

σ(5) ≤ H5 + ln(H5)eH5 15 ≤ 2.28 + 0.83 * 2.28^2.28 15 ≤ 4.39

Since 15 is less than or equal to 4.39, the equation holds true for this specific value of n.

Now we can use the fact that n, a, b, and c are positive integers to make some observations:

4abc = 4 * 1 * 1 * 2 * 3 * 5 = 120

Some possible factorizations are:

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by Complexity Science Hub Vienna

## Hypothetical scenarios

Multidimensional, hard to change.

Journal information: Communications Physics

Provided by Complexity Science Hub Vienna

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