How many earth years would it take to travel to the sun?

The New Horizons space craft set a record at 36,000 miles per hour, the fastest spaceship relative to Earth ever achieved. The sun is 94 million miles away, so if you divide 94 million by 36,000 mph you come up with 2666.67 hours, or 111.111 days. That’s about 3 months and 21 days, round out to 4 months to be safe.

However, you can’t just launch a space ship from Earth directly at the sun and expect to go 36,000 mph. New Horizon’s speed was achieved through slinging around planets, what we call “gravity assist.” Your sun bound space craft would begin slowly and take a very long time to reach the sun.

If it took the Apollo astronauts 3 days to go 250,000 miles to the moon. At that speed it would take just over 3 years to reach the sun.

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How come some things can escape gravity? After all, it’s supposed to pull everything down. Maybe it is density and not gravity.

It is escape velocity, once achieved, that allows us to escape. Here is an image to illustrate the point. Once you achieve escape velocity, gravity gets weaker as the ship goes outward, and it does not cause the ship to return.

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If a tennis ball flies at 99% of light speed, will it be in every location of its trajectory, or will it skip some on its way?

The tennis ball will not appear in every location of it’s trajectory nor will it skip some on it’s way. It will look to us that time on the tennis ball has slowed down.

Time and space are relative. What this means to your question is simply the speed of the tennis ball must be measured in relationship to something else, namely us on Earth.

If the tennis ball is launched from Earth and goes 99% the speed of light from Earth, then microbes and insects on the tennis ball would appear to be moving very slowly. But on the tennis ball, life would go on normally and life on Earth would appear to be going very quickly.

However, on the tennis ball itself, once that speed is achieved, it will appear that the tennis ball is standing still and Earth is moving away very quickly. If you were little and stood on the tennis ball and turned on a beam of light, the light would leave your flashlight at the speed of light in all directions.

Screenshot_2017-04-04_20-31-08How is that possible since light only travels the same speed in a vacuum? Because time slowed down for you, and so light always travels the speed of light, even though you seem to be normal. That’s why space and time are interwoven in the same fabric, what we call spacetime.

The same for us on Earth. We are orbiting the sun, the sun is orbiting the Milky Way center, the whole galaxy is about to collide with Andromeda, etc. etc. But as far as we’re concerned, we’re standing still and light leaves our beams of light at the speed of light.

Near-Earth Asteroid Flyby

Asteroid 2017 FE1 was first observed by Mt. Lemmon Survey on 2017-03-18

It will fly by Earth harmlessly on 2017-06-16 at 22:16 UTC at 39.9 times the distance to the Moon, at a speed (relative to the Earth) of 10.6 km/s.

It is estimated to be 164 – 518 meters in size.
#space#science#Astronomy#astrophysics#asteroids#NEO near Earth objects#physics

Why do aliens always have to look and have similar biology to us?

Exactly! To date, no life has been found on any other planet or meteor. We would really like to find life elsewhere, and the most likely candidates within reach would be the moons of Jupiter and Saturn.

Beyond that you have to go interstellar. Since it would take hundreds or even thousands of years to reach even the nearest stars at the fastest speed we’ve ever achieved in space, interstellar travel is unlikely now or in the future.

Put away Star Trek and Star Wars. Aliens are not visiting us and we are not going to visit them, whatever they may look like.

Have the space missions carried out to date ended up as well as possible, and, for that reason, there haven’t fortunately been any fatalities in space?

The Moon is not as Close as you Think!

Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune could all fit in the gap between the Earth and our Moon with about 4,990 miles to spare

Think of Earth as a basketball and the moon like a tennis ball. How far would you have to place them apart to approximate the distance between the Earth and Moon? Five feet? Ten feet? Twenty feet? Nope! Further even then that! A tennis ball would then have to be about 24 feet from the basketball to be of the proper scale. Farther than most people visualize.

This is how it looks (See image). Kind of surprising. The moon looks bigger to us than that, doesn’t it? Well, no it doesn’t. Our minds eye just makes it look bigger. Hold your thumb out at arms length. The tip of your thumb at that distance more than covers the moon. Still, the moon is the biggest thing in the night sky, and it really stands out much brighter and bigger than all the stars, relatively.

Surprisingly, people really do think the Moon is closer to the Earth than it is. You can see from the photo taking a “mere trip to the Moon” is no easy task!

Here’s a statistic for you! Think how big Jupiter, Saturn, Uranus and Neptune, the gas giants, are in relationship to our tiny Earth.

Yet our Moon is so far from Earth that Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune could all fit in the gap with about 4,990 miles to spare (using the average Earth-moon distance of 238,555 miles).

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