Direct answer: Cosmologists classify the universe as open, flat, or closed based on spatial curvature. Current cosmic microwave background (CMB) measurements indicate the universe is very close to flat, but small curvature remains observationally allowed. Whether the universe is ultimately finite or infinite cannot be settled by theory alone, since all three curvature types are…
The Einstein Field Equations (EFE) are ten coupled, nonlinear differential equations that describe how matter and energy determine the curvature of spacetime. First published by Albert Einstein in 1915, they form the mathematical core of general relativity, linking spacetime geometry to its energy and matter content through the equation [itex]G_{\mu\nu} = \frac{8\pi G}{c^4} T_{\mu\nu}[/itex]. Key…
Answer: AI, and more specifically machine learning, is already reshaping STEM through faster image and data analysis, automated grading and mastery-learning systems, and accelerated drug discovery in fields like pharma and biotech. Five Physics Forums advisors agree AI will keep expanding into labs, classrooms, and industry, but none expect it to fully replace human instructors,…
Five Physics Forums advisors share contrasting views on artificial intelligence’s effect on STEM fields, jobs, and society. Consensus points: near-term AI will mostly automate rules-based tasks rather than achieve general intelligence, public trust and data bias remain major obstacles, and AI’s biggest impact may come from being invisible and embedded in everyday tools rather than…
Physics Forums advisors expect AI to arrive unevenly across STEM: faster in narrow, well-defined tasks like long-haul trucking routes or lab data analysis, and slower in classrooms and jobs requiring human judgment. Most contributors caution against buzzword-driven adoption and stress that AI’s usefulness depends on whether the underlying problem is genuinely suited to automation. Key…
Today we get to know a little more about Engineering Mentor jrmichler! Tell us a bit about your education and academic years Two years college (UW-Madison) in electrical engineering. Burned out (two semesters of 21 credits, tired of poverty, needed to think some things through), dropped out, joined US Air Force. Four years later, had…
Time to test your science knowledge with a fun 10 question quiz with random questions across all sciences. Difficulty is easy to medium. As always, post your score in the comment thread. Enjoy! Comment Thread
A limit describes the value a function or sequence approaches as its input gets arbitrarily close to a specific point, without requiring the function to be defined at that point. Limits underpin calculus, providing the formal basis for continuity, derivatives, and integrals. When the limit exists, it is written as [tex]\lim_{x \to a} f(x) =…
Experts weigh in: Most revolutionary technologies and discoveries in the next 20 years We asked our Physics Forums science advisors, “What technology or scientific discovery will be the most revolutionary within the next 20 years?” Below are their responses, edited for clarity and readability while preserving each contributor’s original voice. Demystifier “Machine learning will be…
Don’t forget to read Part 1 of this interview. Peak Oil and Future Energy Sources Professor Kaku, what do you think of “peak oil”? How serious is it, and what alternative sources of energy do you think will best provide the world’s needs in the coming decades after fossil fuels start to decline (whether it…
We are happy to present this archived interview with Dr. Michio Kaku, conducted in 2004. Michio Kaku is an American theoretical physicist, futurist, and popularizer of science. He is a professor of theoretical physics at the City College of New York and the CUNY Graduate Center. Kaku has written several books about physics and related…
Time to test your inventions, inventors and patent knowledge. As always there is no prize, so try without Google. Post your score in the comment thread. Good luck!
Tell us about your school years? Part of my story is sad but common. I was a poor student. I didn’t pay attention, and I never did homework even once; until one day when it all flipped. That was the day I first learned about differential equations. Diffy-Q was so much fun, that it completely…
Give us an executive summary on bhobba I was born in Toowong Brisbane Australia 17/11/1955, and was raised in suburbs around Toowong – Toowong itself, Taringa and Indooroopilly. I went to 3 schools: Taringa State School, Toowong High and Indooroopilly High. I now live in Redland Bay Queensland Australia. It is about halfway between Brisbane…
We asked our PF Advisors to tell us what their favorite science or math blog is (other than PF Insights). We also have a physics blog list here. Here are their responses…
Physics Forums is pleased to introduce Niels Tuning. He’s a physicist working as the Run Coordinator for the LHCb experiment at CERN. Apart from the questions below you can learn more about him at his website. Niels Tuning also has an active Twitter account here. About Niels Tuning Already as a child I was fascinated…
We asked our PF Advisors to tell us what academic advice would you tell your 18 year old self. Here are their responses… PF Advisors’ Academic Advice Thanks & Next Steps Thanks to all the PF Advisors that shared their academic advice. We have more questions for them in the near future. Stay tuned for…
We asked our PF Advisors to tell us their most memorable or influential textbook and why. Here are their responses… PF Advisors’ Favorite Textbooks Thanks & Next Questions Thanks to all the PF Advisors that shared their favorite textbook. We have more questions for them in the near future. Stay tuned for another “Ask the…
Adam Becker is an astrophysicist and science writer whose first book, What Is Real?: The Unfinished Quest for the Meaning of Quantum Physics, has just been published. Give us some background on how you got interested in physics and formative youth experiences I don’t remember a time when I wasn’t interested in science. Some of…
Clifford V. Johnson is a professor in the Physics and Astronomy Department at USC. He says, “I mainly work on (super)string theory, gravity, gauge theory and M-theory right now, which lead me to think about things like space-time, quantum mechanics, black holes, the big bang, extra dimensions, quarks, gluons, and so forth.” Clifford V. Johnson…
Let’s see how well you know your science book authors. Some are classic, some modern! Don’t forget to post your score in the comment thread linked at the bottom.
The 2017 August Eclipse really was something special. Fortunately Physics Forums has great photographers and snapped some remarkable shots. Here are a few highlights.
Interview: From Biology to Programming, Sysadmin, and Life in New Mexico What got you interested in biology? I was an amateur naturalist as a kid. I kept collections of all sorts and a small menagerie — much to my mother’s dismay when an anole got loose in the basement. I graduated from college with a…
Time to test your scientist photo recognition skills! As always please post your score in the comment thread at the end. Ready for your next quiz? How well do you know about inventions?
Please give us a bit of background into your educational and professional life. I’m a public school kid through and through. After going to the local high school where I grew up in Westford, Massachusetts, I attended Michigan State University to earn a bachelor’s degree in astrophysics (with several extra classes in Computer Science). From…
Video Q&A: Fraser Cain (Universe Today) Special thanks to Universe Today founder Fraser Cain for this fascinating video Q&A. All questions were provided by members of Physics Forums. The full question list appears below the video. Read the next interview with astronomer Pamela Gay.
We are pleased to introduce Sabine Hossenfelder. Sabine is a theoretical physicist at the Frankfurt Institute for Advanced Studies. She also authors the popular physics blog Backreaction. Interview: Sabine Hossenfelder Reading your blog over the past 6 months or so, one gets a feeling that your views about (particle) dark matter versus modified gravity have…
We have an amazing count of over 320 Insights published at Physics Forums. Now we test to see how much you remember from some of them. If you need a hint feel free to read the corresponding Insight which is linked at the end of the question. Good Luck and remember to read future Insights…
Since the mid 20th century NASA has been a force in aerospace research and programs. Let’s find out just how much you know about it’s history, programs and research. Don’t forget to post your score in the forum thread. No prizes, so don’t Google it. :) Ready for your next quiz? How well do you know…
Give us a little background on Jim Hardy Born and raised in Miami, Florida, to parents with roots in Springfield, Missouri. So at heart I’m a small‑town Midwestern fellow. Miami was small in the 1950s, but it became cosmopolitan and outgrew me. I spent a career working in the nuclear plant south of Miami, so…
Give us a brief history on stevendaryl I was born and raised in the American South, mostly living in Georgia. It’s a Southern tradition, for some reason, for kids to be called by their middle name, so my friends call me “Daryl” even though my first name is “Steven”. I grew up in a family…
Stephen Hawking has been a giant in the science world for decades. He has been a accessible figure with his willingness to reach out to the public in various ways. Time to see how much you know about him. There are no prizes so no Goolging! Post your score in the discussion area. Ready for your…
For those who don’t know the great David Hestenes, he is the inventor of the geometric algebra formalism of physics. Here we go! 1) What is the best application of geometric algebra in theoretical physics that you can think of? In other words, what application shows the power and elegance of geometric algebra best? The…
We are pleased to share with you an interview with PF Science Advisor and one of our founding members: DrChinese Who is DrChinese and share some early experience that got you interested in science. I am a Dallas, Texas, USA boy, now married with grown kids. I got very interested in science at a private…
We are pleased to introduce David J. Griffiths, one of the most successful physics textbook authors. Odds are if you studied physics in college, you’ve used one of his textbooks. We are honored to share some of his insights on quantum mechanics and the academic world. Please give us a background on your educational background…
Summer is almost over, but the fun doesn’t have to stop! Take a look at the photos below and see if you can identify them. Post your score in the comment section. Good luck!
Give us a little background on yourself? I was born in Washington DC, grew up in Texas, bachelor’s in physics from Harvard in 1978 but found a career in system software instead. Son of two law professors and grandson of a third, raised a Quaker although it didn’t stick, keep a small fleet of well-rusted…
We are pleased to introduce Sean Carroll. Sean Carroll is a theoretical physicist at Caltech specializing in cosmology and quantum mechanics. He has a new book, The Big Picture, which addresses “On the Origins of Life, Meaning, and the Universe Itself.” Key Points Sean Carroll grew up near Philadelphia and studied at Villanova University. His…
For ages it has been Earth’s little sister. Find out just how much you know about the Moon and our relationship with it. Please post your score in the comment section. Ready for your next quiz? How well do you know about NASA?
We are pleased to introduce Peter Krautzberger. Peter is a manager for MathJax, the technology behind the display of equations on Physics Forums. “The core of the MathJax project is the development of its state-of-the-art, open source, JavaScript platform for display of mathematics.” Please give us a bit of background on yourself I was born…
DrClaude is a mentor at Physics Forums! What brought you to Sweden from Canada? Life, the Universe, and Everything. While in Canada, I was offered the opportunity to do part of my studies in France. After my Ph.D., I stayed in France for postdoctoral work. I tried getting an academic position in France, but it…
PeterDonis is a Physics Mentor at Physics Forums. About PeterDonis I have been interested in science since childhood. I hold two degrees in Nuclear Engineering (focused on fusion rather than fission), which are effectively degrees in plasma physics. I was also Navy ROTC and served six years in the U.S. Navy after graduation. After that…
Please give us a bit of background on your life and professional experience Life: Born and educated in Italy; I then spent 10 years in the United States and 15 in France. I came to physics late: before that I was more into hippie dreams and even trying to overthrow the Italian government. Professional: In…
Have you been keeping up with reading each PF Insight? Let’s find out! Every question’s answer can be found in a PF Insight. Hint links are included if you need help. Be sure to post your score in the comment area.
Garrett Lisi is a theoretical physicist and Physics Forums member who developed the E8 Theory, a proposed geometric framework for unifying particle physics using the E8 Lie group. He splits his time between physics research in Maui and surfing, and in 2007 his E8 Theory paper drew both mainstream media attention and sharp criticism from…
Can you give us a brief history of berkeman? I grew up in a military family (my dad was an Army colonel), so we moved all over the place when I was a kid, finally settling in Calistoga in the northern part of the Napa Valley, California, for my high school years. Being a military…
Give us a brief history of Borek Note: text below is of a negative pedagogical value, don’t read it if you are younger than 20, attending school or still naïvely hoping for the best. I was born half a century ago, in a galaxy far, far away. So far away our laws were all shifted…
This is a new Interview category for Insights. While I line up some great new interviews I’ll be migrating some previous mentor interviews. ZapperZ is a staff emeritus at Physics Forums Can you give us a brief history of ZapperZ? Without reveal things that are answers to a few of the security questions to my accounts,…
Think you know your famous science quotes? Let’s find out in this 12 question quiz. There are no prizes, so it doesn’t pay to Google. Try your best on your own. Report your score in the comment area at the bottom. Good luck!
Let me introduce you to Andy Resnick, a long time Science Advisor at Physics Forums. Tell us a little bit about how you developed an interest in biophysics That’s a good question, and I’m not sure how to answer. I’ve worked in the ‘in-between space’ for many years- for example, optics is in-between physics and…
This is a new Interview category for Insights. While I line up some great new interviews I’ll be migrating some previous mentor interviews. Doc Al is a physics mentor for Physics Forums Can you give us a brief bio? Okay. It was never easy for me. I was born a poor black child. I remember…
This is a new Interview category for Insights. While I line up some great new interviews, I’ll be migrating some previous mentor interviews. About Russ Watters Russ Watters is an engineering mentor for Physics Forums. Brief bio I’m 37, I live outside of Philadelphia and I have a BS in Mechanical Engineering from Drexel University….
Ice is the solid form of water, and understanding its basic properties (freezing point, density, crystal structure) helps explain everything from why it floats to why polar ice matters for climate. This guide answers eight common questions about ice ahead of the first day of winter, December 22nd. Key Takeaways Water freezes into ice at…
This quiz tests reader knowledge of NASA’s New Horizons mission to Pluto, covering key facts and discoveries reported during the mission’s flyby coverage. Take the quiz below to see how much you remember, then share your score in the comments. Pluto in the News Pluto has been a frequent subject of coverage in recent months,…
Evolution is the process by which populations of organisms change over generations through three interacting mechanisms: random genetic variation, inheritance of traits from parents to offspring, and natural selection, which favors traits that improve survival and reproduction in a given environment. Over long timescales, these mechanisms can cause populations to diverge into new species or…
Eugene Cernan became the last person to walk on the moon on December 11, 1972, during NASA’s Apollo 17 mission, closing out a nine-mission lunar exploration program that ran from 1969 to 1972. Across six successful landings, Apollo astronauts returned 842 pounds of lunar samples, tested crewed deep-space survival under crisis conditions during Apollo 13,…
Isaac Newton (1642-1727) was an English mathematician, physicist, and astronomer widely regarded as one of the most influential scientists in history. His work established the foundations of classical mechanics and calculus. Key Takeaways Isaac Newton lived from 1642 to 1727 and worked as an English mathematician, physicist, and astronomer. Newton is credited with foundational contributions…
The Large Hadron Collider (LHC) is the world’s largest particle accelerator, built by CERN beneath the France-Switzerland border near Geneva. It began operating on 10 September 2008 and is best known for providing experimental evidence of the Higgs boson in 2012. This quiz covers its history, function, safety record, and upcoming upgrades. The LHC officially…
These are some of the best physics blogs, updated regularly, written by some of the top minds. The feeds are updated on page refresh, so bookmark this page and you’ll have a quick overview of all the blog’s latest entries each time you visit here. We also asked our community advisors which physics blogs they recommended….
The periodic table is a chart organizing all known chemical elements by atomic number, electron configuration, and recurring chemical properties. Dmitri Mendeleev created the first widely adopted version in 1869, arranging elements by atomic weight. Since then, chemists have proposed hundreds of alternative layouts, and the table continues to be updated as new elements are…
Richard Feynman won the 1965 Nobel Prize in Physics for his work on quantum electrodynamics and is known for inventing Feynman diagrams, contributing to the Manhattan Project at Los Alamos National Laboratory, and writing “Surely You’re Joking, Mr. Feynman!” This quiz tests specific facts about his career, publications, and teaching approach. Richard Feynman remains one…
Albert Einstein developed the theory of relativity and the mass-energy equivalence formula E=mc², won the 1921 Nobel Prize in Physics for his explanation of the photoelectric effect, and his work underpins technologies such as GPS navigation. This quiz tests specific facts about his life, theories, and scientific legacy. Key Takeaways Albert Einstein won the Nobel…
This piece is intended to have a logical basis but should not be taken as purely factual or legal advice. Outer space law leaves several activities in a legal gray zone: space-based defensive lasers are not clearly banned, satellite broadcasting into another country generally requires that country’s consent, spy satellites are lawful under the Outer…
Bioethics asks how far new biological technologies, such as genetic engineering, cloning, and stem cell research, should be allowed to reshape human life, and it argues that scientific capability alone cannot answer that question. Ethical anchors, public education, and policy must develop alongside the science itself, or profit-driven applications risk outpacing society’s ability to manage…
A solar eclipse is safe to view with the naked eye only during totality, the brief period when the Moon completely covers the Sun. At every other stage — partial phases, annularity, or the run-up to totality — you must use certified solar filters (such as eclipse glasses meeting ISO 12312-2) or an indirect method…
Stellar death outcomes depend on the star’s initial mass: stars below roughly 8 solar masses end as white dwarfs, while more massive stars undergo core collapse, exploding as supernovae and leaving behind neutron stars, pulsars, or black holes. Supernova 1987A, observed on 23 February 1987, confirmed that most explosion energy escapes as neutrinos rather than…
The Physics Forums Crackpot Index is a point-based checklist used to evaluate whether a scientific argument is being made in good faith. Higher point totals indicate more red flags associated with pseudoscience, unfounded theorizing, or bad-faith debate tactics. Compiled by Physics Forums staff and advisors, the list catalogs recurring patterns in formatting, rhetoric, sourcing, and…
Hand-to-hand combat, or close-quarters unarmed fighting, works because good technique applies basic physics — acceleration, force, momentum, and energy — through timing, balance, and efficient movement rather than raw size or strength. Grappling arts rely mainly on leverage; striking arts rely mainly on speed and timing to generate power in tight spaces. Key Takeaways Kinetic…
Meet a Mentor is a biweekly (twice a week) series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Today we meet: Integral Can you give us a brief bio? I am a 2nd generation Oregonian born smack in the middle of the 20th century. My dad came…
Meet a Mentor is a series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Today we meet: D H Give us a brief history of D H I spent my childhood in Minnesota, the first nine years in Minneapolis and the last nine on a farm. I…
Meet a Mentor is a weekly series to help you get to know your wonderful mentors better. Constructive questions and comments are welcome! Today we meet: George Jones Give us a brief history of George Jones. On my mother’s side, my roots in Canada have been traced back to the late 1600s; on my father’s…
Meet a Mentor is a biweekly (twice a week) series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Today we meet: Evo Can you give us a brief bio? I’ve been in love with science as long as I can remember. As soon as I began to…
Meet a Mentor is a fun series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Today we meet: Lisab Give us a brief history of Lisab I didn’t follow the usual education route. I dropped out of school in about 8th grade to hang out with my hoodlum…
Meet a Mentor is a fun series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Today we meet: @Ryan_m_b Give us a brief history of Ryan_m_b I’m in my mid-twenties, spent most of my life living in a small town on the border of the countryside, but…
Meet a Mentor is a series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Today we meet: Mark44 How did you become interested in mathematics? Along about 4th grade I came across an algebra textbook that really fascinated me, with all of its x’s and y’s, and…
Meet a Mentor is a weekly series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Meet the Mentor: jtbell Can you give us a brief history of jtbell? I went to a small, liberal-arts college in a Midwest village in the US. There were only three physics…
Meet a Mentor: DaleSpam Meet a Mentor is a fun series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! About DaleSpam Today we meet: DaleSpam. Give us a brief history of DaleSpam I have moved around a decent amount during my life: Arizona, Indiana, Colorado, Texas, Michigan,…
Meet a Mentor is a fun series to help you get to know your wonderful Mentors better. Constructive questions and comments are welcome! Today we meet: @Chestermiller Give us a brief history of Chestermiller Born January 1942 in Brooklyn, NY. Samuel J. Tilden High School, graduated June 1959 (Captain, Math Team). Cooper Union for the…
Evolution is the scientific theory explaining how species change over generations through mutation, heredity, and natural selection. It is supported by fossil evidence, genetics, comparative anatomy, and direct observation, and it does not require rejecting religious belief, violate the second law of thermodynamics, or depend on random chance alone. Key Takeaways A scientific theory is…
Evolution is supported by multiple independent lines of evidence: the fossil record, comparative anatomy and genetics, vestigial structures, directly observed cases like antibiotic resistance, and the simple logic that variation, inheritance, and selection acting together over generations necessarily produce change in populations. Key Takeaways Fossils arranged by geological age tend to show older forms that…
Digital modeling gear uses digital signal processing (DSP) to approximate the tone and dynamic response of analog amplifiers and effects. Examples include the Fender Cyber-Twin, the Line 6 POD, and the Rocktron Replitone. These devices let guitarists access multiple amp voices and effects in a single compact unit instead of relying on a room full…