Earth Definition and 1000 Threads

An asteroid that will be the largest during the year 2021 is expected to pass by about two million kilometers from Earth without the risk of colliding with it, but this astronomical event will allow scientists to study this celestial body more closely. This asteroid is called “2001 FO32”, and...

Well, okay, I should say: what does Newtonian gravitation look like in a ##2+1## dimensional Newtonian universe? Consider a flat Earth, i.e. a region ##\mathcal{E} = \{ (x,y): x^2 + y^2 \leq R \}## with mass density ##\rho##, then for ##r > R## a natural guess for the gravitational field seem...

If the Earth did not rotate, would one side always face the sun and the opposite side always be in darkness? Or would a day be six months, and a night be six months? Or something else?

The Earth's circumference at the equator is 24,901 miles, or 40.075 million meters. It rotates completely once a day or in 86400 seconds. The speed of sound is 343 m/s and the Earth moves at the equator at 40.075 million m/86400 s = 463.831019 m / s which is clearly faster than the speed of...

I know how to solve this using work energy theorem but how can one solve it starting from the fact that net force is centripetal? My attempt was "this means we only need an "anticentripetal" force of same magnitude, but centripetal force does 0 work hence new force also 0 work to counter it"...

I first began to identify the various events in the problem. I call the rocket ##S'## and the Earth ##S##. Sending signal Tail signal reflection Head signal reflection Tail signal return Head signal return For the Earth I know that: ##t_4 = T## ##t_5 = T + \Delta T## Since the two events...

Will the supernova explosion of Betelgeuse influence the Earth's climate and temperature or even the sun in any significant way?

It is recently claimed that between 1800 and 800 million years ago, Earth was flat. This is supposedly indicated by lack of minerals that should have formed in mountains´ roots. However, from that period, there are rocks formed in orogeny - mountain forming processes. For example Grenvillean...

Perseverance's successful landing has scared up some UFO conspiracists online. I used to be like them and I was into Charles Forte as well, encouraged by people who should have known better (yes I AM looking at you Arthur C. Clarke) until I realized I just really wanted to believe rather than...

I have a question : If we consider the change in g due to distance from the Earth core; then y=distance from earth’s core t=time G=gravitation constant M=Earth’s mass k=GM $$y^2(t)=\frac{k}{y(t)^2}$$ If we consider air resistive force as proportional to speed squared, then: m=falling object...

If we think about the forces acting on an object at the surface of the Earth, these forces would be the weight force (mg) pulling downwards and the normal force (N) acting upwards . If the Earth were to stop rotating, then according to Newton's first law the forces must balance, meaning the net...

Take for example earth. Earth has angular momentum about its own axis. However, if we ignore the orbital portion, the angular momentum of the Earth relative to the sun's axis is the same. Another example is the spinning bike wheel/person holding it in a chair. It has angular momentum about its...

In this case, γ = 1/√(1-v^2/c^2) = √(1-0.6^2) = 0.8 However, I'm not sure if time observed by Earth is proper time or moving time. The definition of proper time in my textbook states that it is 'the time measured in a frame of reference where the events occur at the same points in space. I'm...

There may be too much absorption and distortion by the atmosphere of the faint images when viewed from Earth.

Hello All On mid-winter's day, where is the darkest place in the northern hemisphere, and at what time? I'm assuming no moon, no northern lights, and no local light pollution. Would it be at the North Pole? best regards ... Stef

I passed O level Physics in 1983 and loved it but went down the arts route. Over the last 5 years or so I re-kindled my interest and have been reading a lot e.g. Hawkings, Al Khalili, Rovelli etc. I am still struggling with various things that relativity throws up. For example I understand...

Hello everyone, happy holidays! Y/day i googled that question (see title), and i found no clear answer, and I was really suprised, So I had to investigate my self, this is a super basic question, Let me know if i got this right: Earth R: 6,371 km Moon R: 1,737.1 km d1: 384,400 km (center to...

I have several questions related to gravity. I first need to know if gravity decreases at a steady rate for very 1 mile higher up we go?

So, I decided to do Fg=ma I tried 25(9.8)=1.62m m= mass However, when i did it i got a mass of 151 but when i put it into its separate equations, the fg is not 25x larger so fg=ma fg=151(9.8) = 1479.8and then fg=ma fg=151(1.62)= 244.62 but 1479.8/244.62 is not 25 it ends up being 6.05...

The upcoming conjunction of Jupiter & Saturn has got me thinking. I wonder if it has ever been observed (and hopefully photographed) of one planet's disc even partially taking over another's. I have seen a photo of Saturn doing this with the Moon, but I don't think I've ever seen one of a pair...

Hello, i'm doing a project where the goal is to get the relative position of a space object to the earth, roughly. Basically, i want to say that this object is currently e.g. above New York. The data for any given space object that i have is (It's sourced from an NASA API). The specific...

when electron is moving around it like it accelerate and so it create magnetic field. and when mass accelerate it create gravity radiation , we also know that the gravity is not actuall force and it just change the time so when the Earth move in 4 direction it change it path becuase time change...

I tried to solve the problem in 2 ways, first using lagrangian mechanics and second by putting a rotating reference frame on the initial take-off point. However I cannot be sure if the equations of motion for the two solutions came out the same. A-) Equations of motion from Lagrangian...

I started by finding the main events: Sending the first message Receipt the first message Sending the second message Receipt the second message Now, what we know is the time by ##S'## (comoving frame with the spaceship) ##T_1'## and ##T_2'## remaining to arrive to the Earth measured at...

Disclaimer: I'm not actually sure which acceleration is proper and which is coordinate, and I can't recall the source for the half-remembered equation. I spent some time going through my bookmarks, but it was to no avail. Sorry about that. So, general relativity removes the idea of gravity as...

I know I need to solve for acceleration as I am not on Earth and I am assuming I should create a distance vs. time graph. But overall I am unsure what to do. Please help been stuck on this for a while.

Does the Earth flip on its axis? I know the magnetic field will flip every 200,000 years or so but I am asking about the entire earth. I have made a model of an Earth by drilling 2 perpendicular holes in a pool cue ball, filling them with lead and spinning it in a cushion of compressed...

a. V=-GM/r V=-6.67*10^-11*6.0 x 10^24/6.4 x 10^6 V grav = -62531250 ~ -62.5M Jkg^-1 b. To find the gravitational potential 200 km above the surface of the Earth; r=6.4 x 10^6 +2*10^5 m=6.6*10^6 V grav=-6.67*10^-11*6.0 x 10^24/6.6*10^6 V grav= -60636363 ~ -60.6 M Jkg^-1 Can I check that it is...

Which appeared first on Earth, animals or plants? Also, which appeared on land first?

Hey everyone, lately I read a german newspaper article about an Asteroid which passed Earth in a very small distance (asteroid 2020 QG, distance of closest approach was about 2950 km). Here is another link about this event written in English: Article about 2020 QG (Businessinsider.com). As far...

I had read somewhere that this value is 130 °F at sea level (and thus the 134 °F one at Death Valley back in 1913 is suspect). Is there some paper that explains how this figure was derived?

Apologies in advance if this has been touched before. If the Earth has 81 times the mass of the Moon, why the Moon has 1/6 of the gravity of the Earth?

I bought a fun gadget from China. It's a model of Earth levitating in a magnetic field. I filmed it in operation to share with my friends, but I thought I would share it on PF too :smile:. I bought it online here. Film clip: I speak Swedish in the clip, and what I'm saying is this: "...

I'm trying to better understand the physics of how Earth ground works. In circuit analysis and other electronic courses they usually present a conceptual picture like below where the Earth is viewed as a path that completes a circuit? In this conceptual view, the current travels on the...

My solutions (attempts) : a> w=v/r | r=6.35x10^6m | therefore V=7.04x10^-5 m/s b> speed of rotation is faster at the equator than the pole as w=v/r. As w remains constant, as r increases towards the pole V has to decrease. c> F = W - R d> Stuck here. I presume that I have to use the equation...

I understand that there are a few of these still out there that have basically become Earth-crossing asteroids. It would seem that they wouldn't be as bright as the recent Chelyabinsk meteor.

I have two 30x10mm2 Earth busbars in switchboard, both are placed on insulators, but connected through various parts of switchboard (ground terminal, rails, door, mounting plate...) What is the minimal conductor cross section allowed for connecting this two busbars directly?

A Problem is posed for a flight from Melbourne to Cairns. Using the formula for rotational speed at latitude - 1) The latitude of Melbourne is approx 38 degrees south with a rotation velocity of 820 miles/hr 2) The latitude of Cairns is approx 17 degrees south with a rotation velocity of 994...

Let's suppose a solar electron moving directly towards Earth's equator at a high speed. This electron meets Earth's magnetic field, which points to the north, at a distance ten times the Earth's radius, where magnetic field is almost uniform. Which will be the direction this electron describes...

Could a hybrid airship like spacecraft ever so slowly shed speed using Mars' atmosphere while remaining low orbit while buoyant enough to serve as a glider?

We have 2 different formulas for escape velocity. and . If we look at the first formula we see that escape velocity is inversely proportional to the square root of Radius of Earth. While in the second formula, escape velocity is directly proportional to the square root of Radius of Earth. We...

Specifically he homes in on the multiverse and the 10^500 number that crops up. Basically he ends up saying that the whole concept of the multiverse virtually renders any TOE into pointless oblivion. So with this in mind I was wondering if I could also use the multiverse as an explanation for...

When you ground something in electrostatics, the potential of that body becomes the potential of the Earth once equilibrium has been reached. In this context, it is usually taken that the Earth is at 0V. There are two possibilities for this. Either the constant of integration is chosen such that...

I've read here the following: "Currently, the Moon is moving away from Earth at a rate of 4 cm (1.5 inches) per year. In 50 billion years, if the Earth and Moon are not engulfed by the Sun, they will become tidelocked into a larger, stable orbit, with each showing only one face to the other"...

Are there any elements found in space but not on Earth?

I read (in "The View From The Center") that Jupiter protects the Earth from collision with large space rocks, asteroids, etc. What I can't get out of my mind is that could it also cause collisions. A large rock (initially not heading for Earth) could be put on a different path by Jupiter's...

In my textbook, the effective force of a particle on a rotating frame is given as below: The diagram is: What I do not understand is the expression for Rf dotdot, which is given as below: According to the book, an arbitary vector Q can be expressed as: So Rdotdot w.r.t fixed frame can be...

Does the negative terminal of a battery have a negative charge due to having a surplus of electrons? If so, then why do the surplus electrons from the negative terminal of the battery not discharge to the human body or Earth (which have a neutral charge) when touched?...thereby causing the...

a) Speed of the spaceship is 0,5 light years/year. Time that it take to travel to the star system, according to the twin on Earth, is: 4,37/0,5 ¨¨¨¨=8,74 years. Total travel time is 17,5 years b) time dilation formula gives to= 15 years is this correct?

The ISS includes a very fancy running machine which astronauts use to maintain fitness. Several astronauts have run Marathons at the same time as the earthly race (London, Boston etc) and, while there have been many press reports of these runs, none has given any indication as to how hard it is...