Recent Posts

Archive

Tags

When your Standing Still, How Fast are you Really Going???


Everything is relative. Your ideas of reality are based on your perception. You perception is limited by your senses and your ability to concentrate on any given moment of the day. We have all had the experience of that moment of clarity and time seems to slow down and our perception of that event seems crystal clear. Or those times when we are bored and waiting for that pot to boil and time seems to take forever. But what about those moments when we are still and quite and just open to what's going on around us? Some people refer to this as meditation or prayer. But are we really still? It seems that we are, relative to everything around us. We seem to be our own center. We are the Axis Mundi of our perception. But is this perception real? Is a still point on earth a reality?

This idea has no basis in reality. The universe is always moving. If you can change your relative position to the earth and look down you would quickly notice that things are not so still, and if you add in the element of time, or the 4th dimension that we all live within, then things become very wild.

So lets begin with the premise that we are standing still and break it down to the constant levels of movement around us. Moving from the closest to the most distant, we will explore the types of motion that we never feel or perceive.

Where You Live

When thinking of your spot in space there are three things that come quickly to mind. The ground that your standing on, the rotation of the Earth and its orbit around the sun. These are all concepts that we learn about growing up. But is Terra Firma really so firm?

The picture above is a great graphic that quickly sums up the motion of plate tectonics. The measurements in the map are in centimeters in the arrow's direction over the course of a year. If you spend a few seconds studying it, you can see that each plate moves in different directions and at different speed. So to figure out how fast you're moving, you have to find the spot where you live.

I live on the North American plate, so I am moving at about 2.3 centimeters a year or about an inch (if your an inches person - I won't judge). If you're in South America, you might be cruising along at about 11 centimeters or 4.4 inches a year. I'm sure your not impressed...yet. You never notice this movement because it so slow and inertia holds you in place. The only time you might realize the earth's actually moving is in an earthquake if it has enough energy (over a 2.0 on the Richter scale) to notice it. Most people are so busy doing their own thing, it usually has to get over a 3.0 for anyone to take notice.

Now the interesting thing about plate tectonics is that the Earth is recycling herself. Much of the rock that was at the surface when the earth formed has slid back down into the mantle and been replaced by younger crust and top soil. In a few billion years, the earth your standing on today will be inside the mantle somewhere surrounded by lava (Luckily, there is a very low probability you will be here to see it).

Upping one step in movement from the tectonic plate your standing on, the next speed vector to consider is the rotation of the earth. But again, it relative to where your standing on our little blue globe. Hopefully you're not a flat-earth people as this will all seem wrong, but then again, you probably don't read this many words at once.

I happen to live in Michigan (USA) so looking at the chart above, I'm rotating at about 1300 km/hr (808 Miles p/hr). Interestingly, if you happen to be at the precise geographic North or South Pole, your standing there, while your feet rotate 360 degrees every day, but you have no movement in regards to the earth's rotation. At the equator, the widest part of the globe and the fastest in tangental movement, your spinning at 1650 km/hr or about 1025 Mp/hr. Astoundingly, this is 460 meters per second! Now were getting warmed up.

Right now, I am sitting in my chair moving at about 808 Miles p/hr and thinking that this is actually faster than the speed of sound. Its at about 767 mph (343 meters per second), give or take temperature and air density. Why are you not constantly not experiencing sonic booms? Because its relative... If you go out side and run as fast as you can,

(AS FAST AS I CAN - YES) your breaking the speed of sound without sweating it. The reason why we don't experience the sonic boom is because the air molecules that generate the sonic boom, when the sound barrier is broken, are also traveling along with you at the same speed. So to create that sonic boom you have to add your velocity to the ambient air velocity to successfully create the sonic boom. A sonic boom is created by sound getting tied up in the gases in a compression wave, and is not just a function of speed.

As mentioned above, the next factor in figuring out your still velocity in the universe is the orbit of the earth around the sun. Most of us realize that the year is 365.25 days and that's the time it takes to go around the sun in one orbit to arrive back at where we started (only relative to the sun!). So how do you figure out the speed of the earth moving in orbit?? We'll its pretty straight forward once you know some distances and a bit of math.

The average distance from the Earth to the Sun is about 149,600,000 km. (Astronomers call this an astronomical unit, or AU for short.) Therefore, in one year, the Earth travels a distance of 2×π×(149,600,000 km). This means that the speed is about: speed = 2×π×(149,600,000 km)/(1 year)

and if we convert that to more meaningful units (knowing that there are, on average, about 365.25 days in a year, and 24 hours per day) we get: speed = 107,000 km/h (or, if you prefer, 67,000 miles per hour). In seconds that's 18.5 miles a second or 30.22 km/s. Hmm... that seems pretty crazy fast.

What's that in relation to a bullet fired from a gun? Well upon looking it up, a .22 caliber bullet travels at around 800 Miles p/h out of a standard rifle, and converting to feet that's 1173 f/s. Paltry compared to earth's velocity! You are literally speeding around the sun at over 80 times the speed of a bullet. No wonder a small meteor the size of a small car can do so much damage when it hits the earth.

To sum up the first part so far...

Your Speed sitting perfectly still equals:

(Speed of plate tectonic +/-) + (Speed of rotation of earth based on your position) + (Speed of earth's orbit)

But wait, does the sun move? Turns out it does. It is orbiting the center of our galaxy the Milky Way.

Galactic Orbit

The Milky Way galaxy is about a 100 light years across. A light year is the distance that light travels in a earth year's time. Its a big number. Light moves at a velocity of about 300,000 kilometers (km) each second. So one light-year is equal to 9,500,000,000,000 kilometers or about 5,903,026,326,255 miles. Almost 6 trillion miles! A number that is completely unfathomable.

With many years of careful study, scientists have determined that our sun is about 27,000 light years from the center of the galaxy and is rotating around it on approximately a 230 million year orbit. Earth and its neighbors don't orbit within the plane of the galaxy but are instead tipped by about 63 degrees."It's almost like we're sailing through the galaxy sideways and the speed of the sun around the galactic core can easily be figured out using the same math as before.

Now we talked about the earth moving at 80 times the speed of a bullet, but these numbers are much, much bigger.

The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the center of the Milky Way Galaxy. Estimates of the length of one orbit range from 225 to 250 million terrestrial years. To cut to the chase, the Solar System is traveling at an average speed of 828,000 km/h (230 km/s) or 514,000 Miles p/h (143 Miles/s) within its trajectory around the galactic center. The earth is stuck to the sun by gravity and travels right along with it. That speed corresponds to approximately one 1300th of the speed of light.

Just sitting still were talking 143 miles a second. It seems that we all have a need for speed without even realizing it. But there's still more.

Galactic Movement

What about the galaxy? We know that we circle around it's center, but does the galaxy move?

Turns out this is a very hard question to answer, but yep, it does. But how the heck do you figure that out?? In order to figure out speed, you need to have some kind of a frame of reference outside of what your looking at defining. Its that relative position thing. So how can we figure out how fast a whole galaxy moves?

As we discussed the different speeds of our planet so far, we always needed to ask, "Compared to what are you measuring this motion?" In your chair, your motion compared to the walls of your room is zero. Your motion compared to the Moon or the Sun, on the other hand, is quite large. When we talk about your speed going around the Galaxy, we measure it relative to the center of the Milky Way. Now we want to finish up by looking at the motion of the entire Milky Way Galaxy through space.

The Flash of the Big Bang

To understand the reference to our galaxy's speed, we have to think a little bit about the Big Bang, the enormous explosion that was the beginning of space, time, and the whole universe. Right after the Big Bang, the universe was full of energy and very, very hot. In fact, for the first few minutes, the entire universe was hotter than the center of our Sun. It was an unimaginable chaos of energy and subatomic particles, slowly cooling and sorting itself out into the universe we see today.

At that early time, the energy in the universe was in the form of gamma rays, waves of energy like the visible light we see, but composed of much shorter waves with higher energy. Today on Earth, it takes a nuclear bomb to produce significant amounts of gamma rays. But back then, the whole universe was filled with them. You can think of these gamma-rays as the "flash" of the Big Bang, just like fireworks or a bomb can produce a flash of light, the Big Bang resulted in a flash of high energy gamma rays. But these gamma rays were everywhere in the universe. They filled all of space, and as the universe grew (expanded), the gamma rays expanded with it.

When people first think about the expansion of the universe, they naturally think of other expansions they have experience with. I prefer the balloon analogy, as it fits pretty well to the universe's expansion. But the expansion of the universe is not like any other expansion. When the universe expands, it is space itself that is stretching. The galaxies in the universe are moving apart because space stretches and creates more distance between them.

What does this mind-stretching idea of stretching space mean for our gamma rays? The gamma rays are waves of energy moving through space. As space stretches, the waves that are in space must stretch too. Stretched gamma rays are called x-rays. So as the universe expanded, the waves of energy filling space stretched out to become less energetic (cooler) x-rays. As the universe continued to expand, the same waves became ultra-violet light. Later they became visible light, but there were no eyes in the hot compressed universe to see them yet. (Think of the waves of energy in the expanding universe as cooling down and getting less energetic as the wavelengths were stretched out.)

Today, some 12 to 15 billion years after the Big Bang, there has been a lot of stretching. Space has expanded quite a bit. The flash of the Big Bang has stretched until it is now much longer, lower energy waves – microwaves and other radio waves. But the waves have stretched with the space they occupy, and so they still fill the universe, just the way they did at the time of creation.

Astronomers call the collection of all these stretched waves the cosmic background radiation or CBR. Physicists back in the late 1940's predicted that there should be such a background, but since no one had the equipment to find it, the prediction was forgotten. Then, in the mid 1960s, two scientists working for Bell Laboratories, Arno Penzias and Robert Wilson, accidentally discovered the CBR while helping to get communications satellite technology going for the phone company.

Moving through the CBR

What, you might be asking yourself, does all this have to do with how fast we are moving? Well, astronomers can now measure how fast the Earth is moving compared to this radiation filling all of space. (Technically, our motion causes one kind of Doppler Shift in the radiation we observe in the direction that we are moving and another in the direction opposite. This causes the light to red shift or blue shift depending where you look.)

Put another way, the CBR provides a "frame of reference" for the universe at large, relative to which we can measure our motion. From the motion we measure compared to the CBR, we need to subtract out the motion of the Earth around the Sun and the Sun around the center of the Milky Way. The motion that's left must be the particular motion of our Galaxy through the universe!

And how fast is the Milky Way Galaxy moving? The speed turns out to be an astounding 1.3 million miles per hour (2.1 million km/hr)! We are moving roughly in the direction on the sky that is defined by the constellations of Leo and Virgo. We are being pulled towards an area of space deemed "The Great Attractor", which is an area occupied by a large number of galaxies. This dense region of space is occupied by over a hundred million billion suns spread across 100,000 galaxies. The extra gravity in this super cluster of galaxies pulls the Milky Way (and many neighbor galaxies) in that direction.

In the end

So the next time someone in your family or group of friends calls you "lazy for just sitting there", or "look how quiet and still everything is", remark – actually we are whirling about at 1.3 million MPH in an elaborate cosmic dance. We are space travelers going .0019 the speed of light while just sitting here. (Let me know if this get you an interesting reply.)

Other thoughts...

Time Travel...

While it is a concept that's firmly entrenched in modern culture, you can quickly see how traveling a few seconds back ro forward in time will be a catastrophically bad outcome if your time machine cannot travel in through space as well. Just moving a few seconds back in time would leave you stranded in the vacuum of space watching the earth a few hundred miles away. Any calculations in time will also have to include the calculation of space in all the ways details here, plus including the co-efficient of expansion of the universe to arrive in precisely the correct spot. Any miscalculation out to .000000000000001 could leave you trapped inside a wall or underneath the ground. I am guessing this would cause an explosion as the electron shells of all the billions of atoms occupying the congruent space would have to reconcile this. Bad frowny face.

What are we fighting over?

We are constantly fighting over spots of the Earth we want. Sacred places are often a major reason. Once you realize that that sacred spot was only there while the special person or event happened and it has long since moved away from its point of origin, its a bit silly to declare a spot to be special. Get over it. Put up a memorial and move on.

Orbits

There is really no such thing as a circular orbit. They are all spirals or helixes. Once you put time into the mix and see that everything is moving in a direction all the time, the circular orbit becomes a spiral as the sun or galaxy moves through space. (Sun and Earth shown here - you can extrapolate the rest.)

Speed Key:

  • The Earth's orbital speed around the Sun: 30 km/s (108,000 km/h, ~70,000 mph)

  • The Sun's orbital speed around the Galaxy: ~200 km/s (720,000 km/h, 450,000 mph)

  • The speed of the ground beneath your feet, as a result of the Earth's rotation: 1000 km/h (600 mph) at the latitude of Sheffield (53 degrees); it goes up to 1670 km/h (1000 mph) at the equator

  • The speed of light: 300,000 km/s (1.08 billion km/h, 670 million mph)

  • The speed a rocket needs to attain to escape the Earth's gravity: about 8 km/s (5 miles/second, 29000 km/h, 18000 mph)

  • The speed a rocket needs to attain to escape the Sun's gravity, starting from Earth orbit: about 45 km/s (i.e. about 15 km/s in addition to Earth's orbital speed)

  • The speed a rocket needs to attain to reach the Sun: about 30 km/s, because it needs to cancel out Earth's orbital speed - so it is about twice as hard, in terms of speed needed, to reach the Sun as it is to reach the outer planets (about 4 times as hard in energy terms, because energy is proportional to speed squared)

Sources:

1. http://www.dailygalaxy.com/my_weblog/2016/02/solved-the-great-attractor-mystery-hundreds-of-previously-unknown-galaxies-discovered-hidden-behind-.html

2. Wikipedia (various articles

3. https://astrosociety.org/edu/publications/tnl/71/howfast.html

©2017 by Brad Zylman