How Do We Get to Mars?

This is the kind of question, “How do we get to Mars?” that normally would take a lot of discussion and involve a whole lot of mathematics.

I’m going to try to explain it simply and to the best of my limited ability.

Mars is in orbit around the sun. Earth is in orbit around the sun. Earth, being closer to the sun, orbits faster. Mars orbits more slowly. So you have to wait until the two planets are lined up to launch, which happens about every 2 years or so. But it’s not a straight shot out to Mars. Everything works following the rules of orbital mechanics.

Essentially, we launch a spacecraft from Earth into a highly elliptical orbit around Earth. This orbit is so elliptical, that it extends all the way out to the orbit of Mars. You time it so just as this spacecraft reaches it’s farthest point from Earth before beginning it’s return journey, Mars comes along in it’s orbit. The spacecraft meets up with Mars.

Transferring of orbit. A Martian bound spacecraft launches from Earth in an Elliptical orbit, catching up to Mars at the moment when Mars goes by in it’s own orbit around the sun.

The image above from the Jet Propulsion Laboratory website of NASA illustrates how this transfer of an elliptical orbit from Earth catches up to Mars. This process takes about 9 months for a spacecraft like this to reach Mars, and can be accomplished only about once every 2 years.

How often do all of the planets repeat their exact positions? For example, how often would the planets be just as they were on any given date/time, like a birthday or historic event?

by Wayne Boyd Studied Physics (college major) & Psychology (college major) at St. Mary’s University, San Antonio, TX

You see, each planet orbits the sun at different speeds. Those planets orbiting closest to the sun, like Mercury and Venus, orbit faster. Further out from Earth, Mars takes about 2 years to orbit the sun. Further out, Jupiter, Saturn, Uranus and Neptune all take progressively longer. Then the sun itself is orbiting the galactic center once every 250 million years, and the Milky Way galaxy is moving toward the Andromeda Galaxy at about 67 miles per second. So no planet will ever be in the exact position it was before, ever. The first image shows the planets orbiting the sun in relationship to our own solar system. The second image shows the planets orbiting our sun in relationship to the sun orbiting the galactic center of the Milky Way Galaxy.

Why aren’t humans drilling into the center of the Earth?

by Wayne Boyd

I’m a hypothetical billionaire, so let’s discuss financing this project and the chances of success, what we’ll need to get it done, and so forth. Theoretically, it would seem possible.

At the south pole the earth is 12,715 and a half miles in diameter, or about 7900 miles to the center, but at the equator the diameter is 12,756.32 kilometers or 7,926.41 miles to the center. The earth is thicker at the equator and it would take a deeper hole to drill from there. We can make a drill 12.7 miles shorter if we drill from Antarctica. So let’s start drilling there.

From Antarctica, our drill will need to be 3,950.5 miles long to reach the center of the Earth. That’s 300 miles longer than the distance between New York and Paris.

To build a drill like that we’ll have to use a modular design. We’ll start with a shorter drill bit and keep making it longer as we drill deeper until it reaches 3,950.5 miles long.

The drill would need to be really thick and made of some really strong stuff to get through granite and just generally tough layers of rock. A drill tip with diamond heads is probably the way to go. As we drill down, the bit will get dull from time to time and we’ll have to pull the whole drill bit out to replace the head. That might have to be done several times a day.

Can you imagine being 2,000 miles deep at some point and have to pull the whole bit out to replace the head? Sounds like a logistic problem that might slow us down.

Eventually, at some depth or other, we’re going to encounter molten rock. In the core itself is molten iron. Our drill bit will melt. All that trouble for nothing.

It doesn’t sound practical to drill to the center-most point of the earth by drilling from anywhere.

How would life be for us if we were to colonize a super-Earth, assuming the planet is not too far from ours?

by Wayne Boyd – Philosopher, blogger, published author

I don’t know why I’d want to move over to that planet. I’d rather keep working to make things better on this planet. Also, I imagine it might be pretty expensive to move, then I have to buy some land and a house over there, make new friends, and so on. Too much trouble for me.

So to answer your question “How would life be for us if we were to colonize a super-Earth” I would think some people would migrate over there and some people or most people would stay here. I mean, people already have their lives set up here, why move over there?

How big is the Moon compared to the Sun and Earth?

by Wayne Boyd

This is an interesting question. I’m going to answer it with illustrations.

In answer to “How big is the Moon compared to the Sun and Earth?” I’m going to give you some illustrations that will put all of this into perspective. First, let’s look at a comparison of our Moon with Pluto and other dwarf planets in our solar system. Here’s a picture to illustrate.

So here you can see our Moon is quite large! In fact, it’s so large, it’s bigger than all of the known dwarf planets in our solar system, including Pluto!

Even though the Moon is bigger than Pluto, it’s not big compared to Earth. Here’s the comparison of that.

So the moon is relatively small compared to our big Earth. But when you bring the Sun into the mix, then you have to understand that Earth itself is not very big. In fact, the Sun is so big it dwarfs even Jupiter. Here’s the image of that comparison:

So to sum up, our Moon is big compared to Pluto and other dwarf planets in our solar system, but small compared to Earth. Earth itself is like a pebble of sand compared to the size of our Sun. Fortunately for us, the sun is also a long way away, and therefore looms the same relative size as the Moon in our sky.

I hope that sheds some light on the subject! Thanks for asking a cool question.

How come if we flew to the Moon, nobody ever tried to fly underneath the Earth to see what’s really down there?

Hehehe….. Did someone actually tell you nobody has ever flown around the earth pole to pole?

That’s why you should check your facts before believing conspiracy theories! A good place to start is by going to to do your fact checking.

Not only do some satellites pass “underneath the Earth” to see what’s really down there, so have many airplanes. Furthermore, people live down there, past that “wall of ice” at the South Pole.

Here’s a picture of what it looks like for real.

Why is the Moon not being pulled into the Earth from gravitational forces? Is the Moons mass stopping gravity from pulling it any further?

The Moon is being pulled toward the Earth, but it’s forward momentum causes it to miss Earth each time it goes around by a wide margin. This is called an orbit.

However, let it be known that because the oceans slosh around on Earth as it rotates about it’s axis (these are called ocean tides), the speed of Earth’s rotation is gradually slowing down. Billions of years ago a day on Earth was only about 8 hours, and now it continues to slow down. We compensate this twice a year by adding leap-seconds as needed.

This slowing of the earth’s rotation causes the moon to drift further away from us every year by about 1.5 inches, so eventually the Moon will escape Earth altogether and drift away.

It will never crash into Earth.

The Universe is a very big thing…

If you were on the ISS, would the view of the stars be completely clear with the lack of atmospheric distortion and light pollution? If so why aren’t there more pictures of it from their pov?

You don’t understand cameras, do you? Well, a quick lesson then. In cameras (other than cell phone cameras), there’s a thing called aperture. When there’s a bright light the aperture has to be small, to let less light in, so you can photograph something like the Earth. This avoids overexposure of the bright objects in your photo. In space, this blacks out the stars.

However, if like the Hubble Telescope, you just look away from Earth at the stars, you see a whole lot more of them than we can see here on Earth.

Here’s a photo taken of the Hubble Telescope from the point of view of the Space Shuttle Discovery. Notice, because the Earth is so bright, we don’t see any stars.

The Hubble Space Telescope (HST) floats gracefully above the blue Earth after release from Discovery’s robot arm after a successful servicing mission.

On the other hand, since the Hubble Telescope points away from the bright light source coming from Earth, we can capture images like these.

Why have humans never been back to the Moon after 1972?

By Richard Muller, Prof. Physics UC Berkeley, author “Physics for Future Presidents”

There never was much value in going to the Moon in the first place, so there was no good reason to return.

When J.F. Kennedy proposed we go to the moon by the end of the 1960s, his goal was to raise American spirits, to return us to a belief that we could win in a competition with the surging Soviet Union (which was not only beating us in space, but even in the Olympics!).

When Kennedy died, I think we were determined to get to the Moon in the now sacred deadline of the late 1960s, to fulfill Kennedy’s dream.

Scientists liked the Moon shot, primarily (this is my observation, not based on a careful poll) because it injected a lot of money into science in space. If the same money had been made available for science in space, but not involving human transport, then most scientists would have favored unmanned experiments, including unmanned exploration of the Moon. It made much more financial sense, but most people (especially at NASA) believed that without the human involvement, the public would not support high levels of spending.

Once we met Kennedy’s goals, of restoring the US spirit and self confidence, then the financial considerations took over. There simply is not much value added by putting men on the Moon; arguably, there is much science value lost. (Science experiments that have to be man-safe are far more expensive.) On the other hand, you’ll notice that not a lot of money has been spent on sending robots to the Moon. Some, and they’ve done some remarkable things, but not the many billions that go along with a man shot.

Instead, we have spent our resources with unmanned exploration of the solar system, with truly spectacular results. We’ve discovered that every moon of every planet appears to be different from every other moon! (That’s only a slight exaggeration.) The great glory of NASA in the last few decades has been its unmanned program. In comparison, the Space Station has accomplished very little. (Again, that is my personal evaluation.)

How Far Can we Drill into the North Pole?

You do realize that there is no solid land over the North Pole, right? There’s ice floating on the ocean, and the ice sheet moves around as it floats. Underneath the ice there is the ocean.

Therefore, to drill into the North Pole you could just drill a hole through the ice until you hit water, or go to the bottom of the ocean and start drilling on the ocean floor.

There’s no specific reason to do so, however, and doing so would be pretty fruitless.

The North Pole has been reached by walking, by ice-breaker ship and by airplane. In the image below, a woman traveling on the Russian nuclear icebreaker Yamal holds a sign marking the North Pole, however, because the ice drifts, the sign also drifted away from the pole.

Sadly, there’s no Santa at the North Pole.