A lot of people are afraid to swim in the ocean because they are afraid that something slimy, or squishy will touch them. Or worse! A huge shark will take a bite out of their leg!
As humans we tend to be afraid of things we can't see or we see but don't understand...so, what about space...are there spooky things in space?
Look at these spooky pictures from space:
OOOOOOOh! Did you spot the Witch Head Nebula? Or the Horse Nebula? How about the Ghoulish Nebula? Comment on which pictures you liked the best, and what did YOU see?
When our brains try to make sense of an image and try to understand it, we use memories of what we know or have seen before. When we can't make sense of something we "feel creepy", or we feel uncomfortable and a little scared. Once we make sense of the image we feel better. Look at this image that is driving people nuts on social media:
The question is: Can you name one familiar thing that you see? Thousands are going nuts over this picture and have commented that they feel "insane", or "creeped out" or "freaked out". Some people refuse to look at it because it makes them feel so uncomfortable.
Have you seen a gyroscope before, or played with one?
They are like a top and can spin in one place using angular momentum. The special part about a gyroscope is that the insides are free to spin where ever they want.
A gyroscope can steadily rotate and keep its balance...anywhere.
What are gyroscopes used for? They are used in airplanes, space shuttles and jets to name a few. What a gyroscope does is help these vehicles manage different forces while flying in "space". It's kind of like this: You've been in a car, buckled in and traveling in a straight line. Your car can take you places at 80 miles per hour. You can't really tell that you are going that fast because you are "part of the car". When the driver slows and makes a turn while moving, if you didn't have your seat belt on you would lean or slam into the driver. Many cars have handles on the passenger doors that you can hang onto so that you can pull yourself the other way and not fall into the driver. Well a gyroscope, in a more complex way, does the same thing. During travel, a gyroscope helps the object make turns without the object being over taken by those forces you feel in the car when you turn and you want to lean into the driver. While the gyroscope is spinning it is buffering or redistributing that force.
Watch this video to see how a gyroscope works, using angular momentum, and what it is useful for:
And now you know what kind of gift to ask for this Christmas! Thank you very much!
Well...it's an object that is rotating on an axis very fast, like a fidget spinner? An ice skater....Let me show you instead, then I will try to put it into words...
Do you see the axis? The middle thingy in the middle?
Whoa! Is that magic? Nope. It's a spinning top held in space by magnets.
So angular momentum is the inertia of an object rotating around an axis.
Our Moon orbits us faithfully, as do many other Moons orbit other planets in the Solar System. These little moons don't fall into their planets because of gravity and inertia! Moons are so little, why don't they just fly off into the Sun?
I think you could answer that question....
Gravity depends on mass and distance.
In the fabric of space, Earth pulls the Moon toward it...not the Sun, because the Sun is too far away to pull the Moon into it. And we know that the Moon doesn't fall into us because of inertia. The Moon tries to get away, but Earth's gravity keeps it near. Old news!
The shape of Earth's gravity field is not perfectly smooth. Satellites tracking Earth's gravity have created computer images of what this looks like on Earth. Because there are places where there is more gravity than other places, the Earth looks...bumpy...
Earth's gravity field is constantly changing. Because water has mass the satellites (GRACE) can detect where water moves and shifts because of the gravitational relationship between the Moon and Earth. Mountains are red and show where the greatest pull of gravity is, and the ocean basins are blue because they show less gravity. Cool huh?
The model below shows how the ocean's tides are affected by the gravity pulling between Earth and the Moon:
This tidal pulling has made life along the ocean, beaches and the continental shelves rich with animals that need water and solid earth to survive.
So mathematically speaking "the forward movement, or velocity of the moon," keeps the oceans moving and the results of that are fascinating animal life that have learned how to adapt to ocean and land. This makes our visit to the beach, so much more interesting!
Are you bored and want to control the Earth! Mu-ah-ah-ah! Here is a really fun interactive model of gravity and inertia. You get to control the mass of the Sun, you get to control the speed of orbit, you get to control a lot! I recommend checking this out and having some fun this weekend.
This is kind of a no-brainer....objects with greater mass have greater inertia. You know that boulder that sits on top of another boulder? You've been to that park, haven't you?
The top boulder is big and it's not moving...for thousands of years it hasn't moved...it has resisted movement for so long!! Can you think of anything greater that could knock it off its rocky pedestal?
Yep, an earthquake and it would have to be a pretty powerful earthquake too! Let's think of mass this way...
Which would be easier to push?
An elephant or a mouse?
Those two elephants are about the same mass, so the pusher was able to push the other elephant into the water. What about you? Could you, of lesser mass, push an elephant into the water?
We can push different masses to a certain point and then it would be like pushing an elephant, something of greater mass....the greater mass the more resistant it is to movement (INERTIA).
Could we say, the more INERTIA there is, the larger the MASS? Sure!
I love inertia! Being the large mass can be so satisfying!
Remember how I told you our Sun is the largest object in our Solar System, and because of this greater mass, all the gravity in our Solar System is because of the Sun? Well, gravity is constantly pulling on all 8 planets and dwarf planets every day...Why don't the planets get pulled into the Sun?
Whoa! That was a lot of information...basically, what this scientist is trying to tell us is, that, because the planets are moving (INERTIA) already and the Sun is massive (GRAVITY), together, gravity and inertia is what is keeping us from flying into the Sun.
The Sun is pulling us and the Earth is trying to move or escape. Is there an escape velocity? Look at this crazy table of escape velocities of different celestial objects:
Body
Mass
Escape Velocity in Kilometers/ Second
Escape Velocity in Miles/Hour
Ceres (largest asteroid in the asteroid belt)
1,170,000,000,000,000,000 kg
.64 km/sec
1430.78 mph
The Moon
73,600,000,000,000,000,000 kg
2.38 km/sec
5320.73 mph
Earth
5,980,000,000,000,000,000,000 kg
11.2 km/sec
25038.72 mph
Jupiter
715,000,000,000,000,000,000,000,000 kg
59.5 km/sec
133018.2 mph
Sun
1,990,000,000,000,000,000,000,000,000 kg
618. km/sec
1381600.8 mph
Sirius B (a white dwarf star)
2,000,000,000,000,000,000,000,000,000 kg
5,200. km/sec
11625120 mph
Hah! The Earth would have to travel 25,038.72 miles per hour to escape the gravitational pull of the Sun. Remember the two factors that determine the strength of gravity?
Mass and distance. Do you think Earth will be orbiting the Sun for another couple of billion years?
I think it's interesting to look at the masses of the objects...Look at the mass of the Sun and compare that to the mass of Sirius B a white dwarf star!!! Holy Starmass!!
The Law of Gravity states something like this: all objects in the universe have an attraction to each other...doesn't that kind of blow your mind? We can't go anywhere in the universe and not be attracted to something. So, how do scientists figure out how to get from planet Earth to planet Mars?
It's all about mass and distance, the two factors that determine the strength of gravity....
Watch this next video and have your mind blown, or maybe better, some of the muddiness of gravity and inertia will clear up and you will see things more clearly?
We know that "inertia" is for any object, anywhere on Earth and in space. Inertia means that an object is either moving and it's too much work to stop, or the object is sitting and its too much work to get going.
Inertia means "lazy". Sometimes I have lots of inertia....in the morning, when my alarm goes off, I don't want to get out of bed...
Inertia is pretty cool if you can see it:
The leaf example is super cool to watch because you can see most of the leaves resist falling with the lady, they seem to hover over the net for a few tiny seconds. This is leaves resisting change.
In this video we see how water resists change the seconds after the balloon is popped.
Did you see how the soccer ball doesn't want to change it's speed when it has dropped out of the truck? So SICK! I could watch inertia all day long!
Inertia! Lazy objects! That's what I'm talking about!!
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