How would we know if there’s intelligent life on the planet?

 This answer is re-quoted with my permission (from my own website). Take it as a rather interesting answer to your interesting question!

Breaking news. Astrophysicists have discovered a new planet within the “Goldilocks” region orbiting a yellow dwarf star and believe it is teaming with life, thus putting to rest the age-old question: “Is there life on other planets?”

The planet appears to be similar to our own in size and has an atmosphere primarily of oxygen and nitrogen. However, don’t plan on visiting the new world anytime soon. Not only is it many light years away, but microbial life floating in the wind would be a death trap without a spacesuit since we have never developed evolutionary immunity against them.

Observations suggest the surface of the planet is mostly submerged under salt-water oceans which themselves are full of aquatic life of all sizes. The areas that rise above the oceans, approximately 25% of the planet surface, are covered with plant life which provide food for many of the animals that live there.

Evidence indicates the dry land areas are inhabited mainly by germs and insects, however quadrupeds and bipeds live among them. The bipeds appear to be polluting their own air and water due to advanced industrial revolution. Great cities have arisen all over the land and the bipeds appear to have launched satellites and probes into space. Unfortunately, they quarrel and kill each other and share no common interests with their environment.

The planet is located inside the neighboring Milky Way Galaxy, which can be seen from our own Andromeda Galaxy with the naked eye in the night sky, and appears brilliant when seen through even modest telescopes.

Tentatively the planet, has been named “Earth” and due to the circumstances may be barren of all life within a few thousand years. It has been classified as dangerous for habitation and the search for intelligent life on other worlds continues.

Why don’t we see the hidden face of the moon? Is this because the moon rotation is perfectly synchronized with Earth?

You are correct. The moon is synchronized with Earth, although not perfectly. There is a wobble which I’ll show you below.

The “face on the moon” means that some people see what looks like a face on the side of the moon we can see. It’s not on the far side, but the side we see.

Here is a picture of the moon with the “face” outlined that people call the “face on the moon.” It is not meant to be comical (though it looks funny), but outlines the moon features people imagine look like a face.

More below the picture.

Now, here’s a comparison of the near and far side of the moon taken by a satellite we placed in orbit around the moon. On the left is the familiar side of the moon we see facing Earth. On the right is the side we never see from Earth because it faces away from us. This shows the moon is tidally locked with Earth so that one side always faces us. More below.

And finally, here’s an animation that shows that the moon isn’t perfectly synchronized with Earth, as you put it (scientifically it’s called “tidally locked”), but wobbles quite a bit from full moon to full moon. Due to this wobble, sometimes you can get a peak of what’s on the far side. You’ll also notice the moon gets larger and smaller in the animation. This variation happens because the moons orbit is slightly elliptical around us, so sometimes it’s a little closer and looks bigger, and sometimes a little further and looks smaller. A full moon when the moon is closest is called a supermoon.

moon-wobble

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

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).

Solar_System_3

Solution to Joe Drops the Ball

In two previous blog posts about Newton’s Cannon and Joe Drops the Ball I posed the question: If falling objects go faster and faster, why don’t orbiting objects fall out of orbit and crash to the ground?

The question is legitimate and also has a perfectly legitimate explanation.

The rate of a falling object is 32.2 feet per second per second, i.e. it goes faster and faster as it goes down. It accelerates on the way to the ground. So the first question is this: 1) Is an object in orbit in free fall? The answer is yes. 2) Do falling objects accelerate as they fall to the ground? The answer is yes. 3) Do orbiting objects accelerate and thus fall to the ground? The answer is no.

It’s all in the definition of accelerate. Acceleration is a change in velocity not just a change in speed. Velocity is the speed in a given direction, but because an object in orbit is always changing direction it is technically accelerating even if it’s speed isn’t changing.JoeDropsBall5

The force of gravity bending the forward motion of the orbiting object changes the direction of the object. The object is accelerating even if it’s speed isn’t changing, because it is constantly changing direction.

This is alternatively explained in the article I wrote called The Little Rocket that Was.

Venus, Mars and Uranus

If you look outside just after sundown, you will see tonight a very bright star towards the east. That’s not really a star. That’s Venus!

Venus is called our sister planet because it is very near the size of Earth and is on the inside edge of the Goldilocks zone. Scientists believe that if life exists on other planets then those planets must be within a certain Goldilocks zone from their sun.

Just above the bright light of the planet Venus, and a little bit to the left, you will see a very tiny point of light which is slightly orange in color. That’s Mars.

And just above Mars also to the left is Uranus. Of course, you can’t see Uranus with the naked eye. You need a very powerful telescope for that. But it’s there tonight and if you’ve got a telescope like the one below go have a look!