A while back I did a page on the Speed of the Earth through the Galaxy. Wanted to find out how fast an Armchair Astronaut was going sitting at his
computer...
So I figured it would be a good exercise in space navigation... Since Pegasus is working on a saucer, I figured sooner or later we will need a
navigator so we will take applications...
Now a lot of the numbers are approximate as I found them... HEY if I had exact figures I wouldn't need to hire a navigator
I am sure as we go someone will add corrections
What is the Speed of the Earth?
This page deals with the actual speed of the Earth moving through space. There are many directions of travel and various speeds that have to be taken
into consideration.
Why is this of importance? For any discussion on the posibility or the probabiliy of space flight dealing with interstellar flight, it is necessary to
have this data.
Imagine for a moment that you have a faster than light or warp capable star ship...
Considering the speed at which the Earth moves, even a short mission away from Earth would result in the planet being millions of miles away from the
point of origin at the time you left. NASA calculations to reach a simple point like the Moon require enormous calculations and pin point accuracy.
Any small error left uncompensated would result in Astronauts missing the Earth on return.
Motion, Speed and Direction of Travel of Earth Through Space
Or
"How the Hell Do I Calculate the Way Home"
Disclaimer:The following figures are approximate values for demonstration only! Please DO NOT use them to calculate actual flight paths. We are not
responsible for people getting "Lost in Space".
Consider yourself sitting at your computer on a chair...How fast are you moving?
1. The Earth "wobbles" on its polar axis. This motion is not relevant (IMO) to the calculations needed to return to earth from interstellar space
as it is an "in situ" motion, but it exists.
2. The Earth revolves [spins] on its axis. For these calculations we will use the equator with a circumference of approx. 25,000 miles. One rotation
of Earth is approx. 24 hours. Again this is "in situ" motion so not relevant to space travel, but adds to our "stationary chair" model
25000/24 =1041.7 MPH
3. The Earth is orbiting the Sun once a year. The circumference of the Earth's orbit is approx. 607.6 million miles [or 940 million kilometers].
One year is approx. 365 days
365 days X 24 = 8760 hours
607,600,000/8760 = 69,360.73 MPH
So far we have basically 3 Directions of Motion [Wobble, Spin and Orbit] and a combined speed of 1041.70 + 69,360.73 = 70,402.43 MPH for a person
sitting in a chair at the Equator.
[Note: We will do the actual vector calculations at the end]
The following source gives more detail and a more precise calculation based on your latitude and more exact figures. Anyone dizzy yet? A little motion
sickness perhaps?
NASA - What is the speed of the Earth?
imagine.gsfc.nasa.gov...
When you take into account the three-dimensional picture of the Sun's movement through our Milky Way Galaxy, things get very complicated.
4. The sun [and hence the solar system] is moving towards the constellation Hercules, namely to the star Lambda Herculis at 12 miles per second [or 20
kilometers per second] which is 43,200 MPH
5. The Solar system is also moving upwards, at 90 degrees to the plane of the Milky Way, at 4.34 miles per second or 15,624 MPH. But we are actually
leaving the Galaxy, out about 50 light years now and will be moving out to 250 light years before it reverses. Details of the mechanics of this are
explained in the link below.
We also crossed the Galactic plane 2 million years ago.
6. The Solar system is orbiting around the Galaxy at an "estimated" speed of 124 miles per second [or 200 kilometers per second] which is 446,400
MPH. The way that figure has been calculated can be found at the link below.
Stanford University - What is the speed of the Solar System?
solar-center.stanford.edu...
This is where finding our way home becomes difficult, as we do NOT have an actual true figure for this calculation. The further out we go, taking into
account the various motions and speed, the more difficult it becomes to get precise calculations ergo the more room for error. Until we can actually
go and measure the distances, a "best guess" is all we have. Over the past few decades these values have been revised several times, and are
constantly being added to today.
From an Astronomer's point of view this is not a problem, as they are merely observing from Earth and can fix their calculations when they get new
data… no harm done… just reprint the maps.
BUT from a spaceship pilot point of view…touring just within our own galaxy… the problems are enormous.
From a navigator's point of view, we can leave out the "wobble" and the Earth's rotation as those movements are "in place". For later
calculations we could also leave out the Earth orbiting the Sun, because if we can make it back to the Sun, I am sure we can locate Earth.
So our "armchair Astronaut" is now moving through 6 different directions and a combined speed of approximately 574,585 MPH
69,361 MPH Spin and Orbit
43,200 MPH Towards Lambda Herculis
15,624 MPH Perpendicular to Galactic Plane
446,400 MPH Orbiting the Galactic Center [or Galactic Spin Rate]
-------------------
574,585 MPH Speed of Earth within Our Galaxy
So for every hour you are away from the solar system, your planet is moving half a million miles, and in several directions…
Now if you want to leave the galaxy add another 1,339,200 MPH to the calculations. This is the speed the galaxy is moving through the universe. But
THEN you really get into difficulties pin pointing you reference point. Details can be found here…
So you see… the propulsion unit is the least of your worries….
You better have a REALLY GOOD NAVIGATOR.
NASA - What is the Speed of our Galaxy?
helios.gsfc.nasa.gov...
YOU ARE HERE
Oh and about that vector calculation thing? …
--------------Forget it I have a headache! …
----------------------------Go ask a rocket scientist! ...
WANTED: ROCKET SCIENTIST...
JOB: Provide Accurate measurements and vector details for the Scientific Explanation
PAY: The Satisfaction that comes from sharing your knowledge.