Events Definition and 366 Threads

Edit: I'm leaving the original post as is, but after discussion I'm not confused over coordinate time having a physical meaning. I was confused over a particular use of a coordinate time difference to solve a problem, in which a particular coordinate time interval for a particular choice of...

This is an interesting story. I have a couple of friends with kids who need to wear quieting earphones in most public situations, and this seems like a nice way to help families be able to broaden the events that they can attend together. It will be interesting to see if it catches on as a...

1. Which organization or group of organizations is it the responsibility of to detect and track worrisome asteroids? I believe NASA and the USAF track such bodies if I'm not mistaken, but how many others are there? Who is "best" at it, or most relied-upon for spotting and cataloging them? 2...

Suppose someone randomly went to Starbucks Monday thru Saturday between 8:00 AM and 10:AM. Suppose one Tuesday in May they purchased a drink and the credit card transaction occurred at 9:14:12 AM. What are the odds that person could randomly return on a Wednesday in July and purchase a drink...

I have six events with known probabilities ##p_1, ..., p_6##. Find the probability of two or more of these events occurring together? I can't think of a clever way to calculate this without using the problematic "or" is addition rule, but using that rule I get the required probability is P(2 or...

The dude in this video appears to say that "space" (ie a coordinate system that does not involve time ) describes where an event happened but not when. To describe when and where an event happened you need both space and time so if I don't care "when" an event took place, only "where"...

A questionnaire survey on the use of SNS was conducted for students at A University. As a result, we got the following: ##55\%## using Twitter , ##53\%## using Facebook , ##20\%## using Twitter and facebook both, ##19\%## use both Facebook and Instagram. ##76\%## use at least Twitter and...

Popular science: https://phys.org/news/2019-05-scientists-early-moment-megaquake.html https://advances.sciencemag.org/content/5/5/eaav2032 Image courtesy University of Oregon. 15 seconds into a massive event, there is data to support the concept of a warning of a coming massive event. Data...

I'm doing some exercises about special relativity and one of them asks to find the speed in an arbitrary frame of reference (1) in such a way that it perceives two events at the same time that didn't happen simultaneously in other frame of reference(2). Is it correct to state that if the...

From today's news: https://arstechnica.com/information-technology/2019/04/gps-rollover-event-on-april-6-could-have-some-side-effects/ There is an entire class of risks that I could label "infrequent events". The mother of all of them was Y2K. (Y2K bad consequences were avoided via massive...

P. O’Hare et al. Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. https://www.pnas.org/content/early/2019/03/05/1815725116 https://www.sciencenews.org/article/one-strongest-known-solar-storms-blasted-earth-660-bc Extreme solar events, proton events, are not common...

I attended an interesting talk the other day about supernova archeology, and the discovery of strong evidence that Earth was showered with debris from a nearby supernova ~60-300 light years, about 2 to 3 Mya. The evidence is the presence of 60Fe in deep ocean crust at multiple sites, as well as...

In Lee Smolins book Time Reborn he discusses simultaneous events and says events that are far from each other we find that there is no absolute ordering that all observers can agree on. For some observers the two events may be simultaneous for other observers one event may be in the past of the...

Homework Statement Definition: A union of events A,B,C, . . . is an event consisting of all the outcomes in all these events. It occurs if any of A,B,C, . . . occurs, and therefore, corresponds to the word “or”: A or B or C or ... (Figure 2.1a). Homework EquationsThe Attempt at a Solution I'm...

It has been proposed that the gravitational wave events GW170809 and GW170814 , named after their date (5 days difference) were actually a single one which appeared twice and magnified due to gravitational lensing. Both events have very similar parameters and come from the same area in the sky...

Let's say I have a service that publishes events, like eo ("Bought 100 shares of AAPL") e1 ("Bought 100 shares of T") e2 ("Sold 500 shares of TSLA") and there exist stateful services subscribing to the events and whose state depends on the events being processed successfully and in the correct...

Homework Statement Why is it that the probability of getting a queen in my second draw given that the first card was a spade, independent events? What if the first card drawn was the queen of spades? Homework Equations P(A and B)=P(A)P(B)

Homework Statement "Do there exist any event spaces with just six elements?" Homework EquationsThe Attempt at a Solution Suppose ##F_1## is an event space with a non-trivial event ##A##. Then ##F_1=\{∅,A,A^c,Ω\}##. So ##inf(|F_1|) = 4##, since if you remove any of these events, ##F_1## is no...

What do ‘events’ refer to when collisions occur at the LHC. The Higgs Boson was found from a blip in the graph of Events vs Energy at about 125Gev. It shows an excess of events at this energy. But what events are in excess and why does this indicate the existence of a particle?

In looking at this light cone diagram, I'm focusing on the part in purple. I'm interested to know if mathematics reveals the exact potential difference in time perceived by observers of three events as they shift between their different planes of simultaneity. This makes more sense using this...

Hi all, I have a few questions regarding the issue of independence. Many thanks in advance. ##\textbf{1}## If I find that some events ##A, B, C## obey the following formula $$P(A \cap B \cap C ) = P(A)P(B)P(C)$$ it does not necessarily mean that a) they are mutually independent and b) ##A##...

Homework Statement "If ##A_1,...,A_m\in O## and ##k\in ℕ##, show that the set of points in ##Ω## (the sample space) which belong to exactly ##k## of the ##A_i## belongs to ##O## (the previous exercise is the case when ##m=2## and ##k=1##)." Homework Equations Event space: O ##O\neq ∅##...

Hi Imagine we have a lottery, with chance of winning 1 in 1000 (1/1000). I have made computer simulations in order to find confidence levels for winning. At 1000 bought lottery tickets, the confidence of winning is 64.1% and 2000 bought lottery tickets the confidence of winning is 87.1% By...

"Why 2 equally-likely events has each a probability of 0.5 ?" If i explain this saying that is due to the frequences as N goes to infinity, I'm saying a tautology cause it's implied in the definition of probability. So, going to a deeper level, why the probabilities of each of 2...

Okay, so I was watching this YouTube video: Which says that there is no universal chronological order of events. Different observers may have a different order of events and both would be correct. What I wanted to try and understand (in layman terms), is this purely down to how long it takes...

Hey! :o Let $A,B,C$ be independent events. I want to show that $A^c, B^c, C^c$ are independent. We have the following: \begin{align*}&P(A^c\cap B^c\cap C^c)=1-P(A\cup B\cup C)\\ & =1-\left [P(A)+P(B)+P(C)-P(A\cap B)-P(A\cap C)-P(B\cap C)-P(A\cap B\cap C)\right ] \\ & = 1-\left...

I want to do some research on the subject. What sorts of things should I look into? Not looking for religious comments on uncaused causes. ;)

The final question in my homework says: Assume the balls in the box are numbered 1 through 8, and that an experiment consists of randomly selecting 3 balls one after another without replacement. What probability should be assigned to the event that at least one ball has an odd number? I have...

I'm currently stuck on a question that involves conditional probability with 3 events. This is a concept that I'm having the most trouble grasping and trying to solve in this subject. I am not sure how to start this problem. The Question: Given that P(A n B) = 0.4, P(A n C) = 0.2, P(B|A)=0.6...

Does light exist between events? [mod: unapproved source] The above perspective will resolve a lot of paradoxes in QM. Is the above view viable or is it untenable? Are there any evidence to show that photons exist in flight? Are there any evidence of photon trajectories?

I'm reading "Bang!", by Brian May, Patrick Moore and Chris Lintott. On page 40, they say: "So one [observer] may believe A preceded B by a minute, and another that A and B were simultaneous, it is impossible for any observer to see B preceding A. Hence cause and effect are preserved..." But in...

Hey! :o I am looking the following exercise: A medium-sized company has $n = 3$ manufacturing departments. Faults in the production process can occur in these departments. We have the following events: \begin{align*}&A=\{"\text{All departments work without faults}"\} \\ &B=\{"\text{ no...

another couple of M6 events from my seismograph M 6.3 - 36km SSW of Putre, Chile M 6.7 - Bouvet Island region on my seismogram below, the P arrival for the M6.3, Chile event is approx 0652UT the P arrival for the M6.7, Bouvet Is event is approx 1907UT cheers Dave

Homework Statement Hi, I have this question that I've been pondering for a while, I keep flipflopping on what I think is right. I only need help on the last part on whether the events are independent or not, the rest of the text is backstory to the question. I know for events to be independent...

I understand when two observer one at rest wrt Earth and the other in motion wrt earth, two events cannot happen at the same time to both the observer. So, is it, the moment, the observer which was in motion comes to rest wrt earth, would two events now, at once happen at the same time, to both...

I just spent some time on Wikipedia, learning about Schumann resonance, and had a question: How does the Schumann resonance relate to thunderstorms? Is there a direct relationship between the Schumann resonance and the lightning activity; the number of lightning events per second for example...

https://www.nature.com/articles/s41598-017-05796-x Abstract: Milnesium is a tardigrade. They can resist severe dessication, extreme heat, and extreme cold.

Homework Statement Homework EquationsThe Attempt at a Solution Distance between events w.r.t. Earth frame, De = | (1/2)w(t+Γ)2 - 350 - (1/2)wt2 | = 242 m Distance between events w.r.t. train frame, Dt =350 m , correct? As w.r.t. train frame , the train is not moving. But, a person on...

Are there any events in reality, or is everything a continuous process? If events exist, do they have precise beginnings and ends? When a photon hits an electron, is that an event? Does that "event" have a beginning and an end? Could the big bang be considered the only event? Can there be any...

Suppose there are two independent experiments taking place \left\vert \Phi\right\rangle =\alpha _{1}\left\vert \phi _{1}\right\rangle +\beta_{1}\left\vert \phi _{2}\right\rangle and \left\vert \Psi \right\rangle=\alpha _{2}\left\vert \psi _{1}\right\rangle +\beta _{2}\left\vert...

The experiments that have been done to demonstrate that entangled particles are correlated (or anti-correlated) have been designed so that Alice and Bob's measurement events are intentionally space-like separated. Thus demonstrating that the "ghostly action at a distance" is supraluminal or...

My general question is: What is the angular power spectrum C_{l,N,ω} of N weighted (weight ω_i for event i) events from a full sky map with distribution C_l? I'm interested in: Mean of C_{l,N,ω}: <C_{l,N,ω}> Variance of C_{l,N,ω}: Var(C_{l,N,ω}) The question is important, since we observe in...

First I am not sure if this is the correct place to post this thread, but the thread will be about optics, quantum physics and special relativity, so it is a mixed subject. Please watch this video first: This technology allows capturing videos at mind blowing 1 trillion fps, which allows us...

Homework Statement This excresice is supposed to help you understand the basic operations of sets, later used in probability. I am given the following phrases and have to write them in using mathematics. Given three events A, B and C, which belong to sample space S, calculate the following...

Homework Statement Observer O at the origin of a coordinate system is at rest relative to two equidistant space stations located at x=+3.00×10^6km (station A) and x=−3.00×10^6km (station B) on the x axis. In reference frame O, station A sends out a light pulse at t = 0 (event 1) and station B...

Hello PF, I built a small application which I figured some users here may be interested in. The app aggregates news and events in the space industry, allows you to view launch schedules, track the space station, and more. It's called Luna and an early version is available on the Play Store...

The CBC is reporting a drastic rise in international student applications to Canadian universities. University of Toronto applications, for example, are up by over 80%. Many are speculating that this is due to uncertainty generated by the recent actions of the new American president and...

I am interested in your opinion with regards to expectation values of low likelihood events in QM. For example, Boltzmann brains are suggested as a problem in cosmology despite their probability being extremely miniscule. Is it realistic to expect Boltzmann brains and other low probability...

Hi, I am a little "confused" of how to treat a problem stating: suppose you expect 1.25 background (SM) events from one measurement. During one particular measurement, you observe 5 events. What's the probability that you discovered new physics? The standard/basic way to go about it is to...

Sorry for my ignorance... still trying to get to grips... If a lady in the middle of a moving train sends out beams to the front and back of the train. They reflect off mirrors back to her and arrive simultaneously because she can't do an experiment to give away that she is moving forward...