# QuestionQuestion about Kepler's 2nd Law

#### Jennarosity

Hello All,

Brand new here and super excited to geek out with you all about all things Space

I was doing some research regarding the upcoming Mars Perseverance launch tomorrow (yay!)

Came across Kepler's 2nd Law of Motion which seems to indicate that the planetary orbital speed changes with respect to the planet's distance from the Sun.

Also noted that the orbit for Earth is elliptical, not perfectly circular, so in this theory Earth would indeed encounter orbital speed changes along our yearly tour around the Sun.

This is where I am lost and seeking some clarity: if the speed changes, why don't we then feel Earth moving? My understanding was that we humans only feel changes in velocity (direction or speed), which is why when the car is moving a constant rate we hardly feel motion, but if there is a turn or acceleration or deceleration, we feel it. Then again, I suppose any point at which the direction of Earth changes in the elliptical orbit would count as a "velocity" change as well by that token.

What puzzle piece am I missing? Am I just overthinking it? Please help a gal out. It will haunt me until I solve this universal mystery.

Thanks in advance and have a stellar day

#### IG2007

##### "Don't criticize what you can't understand..."
Hello All,

Brand new here and super excited to geek out with you all about all things Space

I was doing some research regarding the upcoming Mars Perseverance launch tomorrow (yay!)

Came across Kepler's 2nd Law of Motion which seems to indicate that the planetary orbital speed changes with respect to the planet's distance from the Sun.

Also noted that the orbit for Earth is elliptical, not perfectly circular, so in this theory Earth would indeed encounter orbital speed changes along our yearly tour around the Sun.

This is where I am lost and seeking some clarity: if the speed changes, why don't we then feel Earth moving? My understanding was that we humans only feel changes in velocity (direction or speed), which is why when the car is moving a constant rate we hardly feel motion, but if there is a turn or acceleration or deceleration, we feel it. Then again, I suppose any point at which the direction of Earth changes in the elliptical orbit would count as a "velocity" change as well by that token.

What puzzle piece am I missing? Am I just overthinking it? Please help a gal out. It will haunt me until I solve this universal mystery.

Thanks in advance and have a stellar day
Well, you are overthinking it. Please don't mind. I don't mean to mean or rude.

Well, we encounter orbital speed changes along our yearly tour around the Sun. But, the thing is, we have the same speed as the Earth. The Earth moves, we move, both of us move in the same speed. And, as Einstein said in his Relativity theories,two objects having same speed and direction will not feel that they are moving in relative to each other. So, here you go, you are answered. Because of the same reason, we don't feel the Earth's rotation as well.

Have a good day!

dfjchem721

#### Helio

What we experience is acceleration, which is what is required to change our orbital speed. Our fastest orbital speed is when we are closest to the Sun (perihelion) and our slowest is when we are farthest from the Sun (aphelion). The speed difference is only about 5% and it takes 6 months for that difference to occur. Consider how fast a carnival ride must change your velocity from one direction to another for you to feel the difference.

Another way to consider it. When you travel toward the north pole, the radius of the Earth gets smaller but the rotation period (1 day) is still the same. Thus your body will encounter a couple of changes in acceleration. One component is that you will be moving at a reduced speed eastward (if you are going north). Another is that you aren't being flung outward as the centrifugal force acting on you by the Earth's spin is less. But these changes require travel time and even jets aren't fast enough to cause our senses to note a change.

IG2007

#### Geomartian

Keplerās second law is a mathematical description of an observation. Keplerās second law is a way to describe and predict planetary orbits without understanding what causes them. Newton recognized the force of gravity but he didnāt know what caused it.

Einstein got part of the way there but critical observations were kept from him.

The current textbooks on gravitation and particle theory will be used to start fires ten years from now. They will be considered a cruel joke and a dead end.

2020 will be the year we leave the dark ages (or WWIII starts). I am not choosy.

Practice your maniacal laughter so that the other Arkham chorus members donāt shoot you for being out of tune. Physicists get both a red pill and a blue pill each day.

#### Catastrophe

##### "There never was a good war, or a bad peace."
Errrrrr, . . . . . . yes, and Kepler's Second Law?

#### Helio

Einstein got part of the way there but critical observations were kept from him.
What restrictions were placed on him?

The current textbooks on gravitation and particle theory will be used to start fires ten years from now. They will be considered a cruel joke and a dead end.
Not likely. Newtonian physics still dominates all engineering schools.

#### Geomartian

He was missing the direct clock comparisons (leading and lagging of earths orbit) and the hard data on the diurnal gravitational or S2 term. You can physically spot the radical perturbations by doing direct satellite continuous measurements as they approach and cross the terminator and elliptical plane. Right angles to the Sun and along Earthās motion.

You wonāt find the missing observations either. You will find equations that will describe something like it except that those equations donāt mean anything. They put a bunch of terms together that look sort of close as long as you donāt have access to a long interval of āuncorrectedā data readings.

The happy ending part is that the wings have fallen off the conspiracy and it is expected to crash in flames at any moment.

The Newtonian physics is descriptive and for most uses accurate. The gravitational texts describing the causes of gravity will be considered some form of mathematical rye ergot delusion. Einstein isnāt responsible for how his theories were misused.

The unification of gravitational theory with particle theory will destroy both the Standard Model and Quantum Theory. A usable form of the Unified Theory has existed for some time now. And No, I donāt have it. Right now, the people who do have the Unified Theory wish they had made better choices.

#### iwnt2kw

I think I have your answer And it's an answer that no one knows about (of) And that is As you know that the sun spins as well as all the planets Well this is caused by the sun's internal pressures and chemical reactions And so forth (atoms , molocules , ect) And I believe that when the sun was formed That a body (of matter) passing by either caused it to ignite And or if it was already burning Then hit the sun and started its spinning motion Or it also could have been (just time) Because when the sun s spins It causes funnels , of heat and cold As it let's off it's light (and heat) and this travels out in a (again) spinning kind of motion As the sun constantly moves around (round and round) And this causes vortexes that not only pull along all of the other planets But also because of the sun's poles (magnetic , gravity) And it's heat Plus the coldness of space And as heat is radiated in an outward direction from the sun And of course We also know that coldness tends to displace it (the heat) This is what causes the planets to turn As the heat and coldness passes around the planets This is what causes them to turn Off course only those that are close enough Will benefit from other factors as well But also the negative and the positive polarities given off by the sun These effects have also contributed to the magnetizing of the planets as well as keeping them stuck in their orbital paths around the sun (this explaination pretty much applies to the whole universe , even black holes) And as for your question We notice the earths shift In the changing of the seasons When the earth tilts And I think , that it is believed that there is a possible dark body (a black hole planet) out side of our solar system That is the cause for our pole shift in the seasons Every year at the same place in our solar system because I think that they assume that this might be where this heavenly body might be located Which gives us a tug At the same point in time every year