Alpha's Adventure in Space
Alpha here with another great adventure story for you!
This one starts a few weeks back when Pam mentioned that 50 years ago humans first set foot on the moon. What an amazing accomplishment!
So I decided to look into the history of space exploration and guess what I found... humans weren't the first living beings to travel to space; animals were!
That's right, the first space explorers were everything from monkeys to newts to fruit flies to rabbits and even cats and DOGS!
Yup! The first flight to orbit the earth and return all the animals back safe and sound was Sputnik 5 and there were 2 puppies on board (Belka and Strelka)... neat!
That was it, I was determined that if Belka and Strelka could make it to space and back, then so could I. And my next adventure was born - - Alpha's Adventure to Space
The only problem was, I had no idea how to GET to space. So it was off to find Pam!
Hey Alpha, what's up?
I've decided I want to go to space!
Sweet! That's an awesome adventure! But I don't know anything about going to space so we're going to need to find an expert to help us.
Luckily Pam knows all sorts of people and so she was able to find us an expert to help us on our space adventure...
Her name is Dr. Ilana MacDonald. She has a PhD in Astronomy & Astrophysics and knows a LOT about space... She was even interviewed by CBC Kids about the 50th anniversary of the moon landing (more on that after the story). She also had the coolest hair and glasses I'd ever seen (and her dress looked like it was made of stars).
She was super eager to help us so we asked her a whole bunch of questions to get ready for our space travels and I made notes in my Space Journal about what I was going to need for my journey.
How did humans get to the moon?
The astronauts who first went to the Moon got there using a Saturn V rocket, which is the most powerful rocket that humans have ever created. The Saturn V rocket is powered using several tons of rocket propellant, some of which is a modified form of kerosene and liquid oxygen. It took over 2000 tons of fuel just to escape the immediate vicinity of the Earth.
Space Journal Entry 1
Ok, so to get to space I'm going to need a rocket and a lot of fuel, which I don't think I can get it from the local gas station.
I know that on Earth things move by pushing against the ground (like the wheels of a car) or the air (like in an airplane), but how does something move in space? What does it push against?
The basis for propulsion systems in space is Newton's third law: for every action, there is an equal and opposite reaction. When the rocket in a spaceship burns fuel, the exhaust is forced through a nozzle and propelled behind the rocketship out into space. There is an equal and opposite force that is then exerted on the rocketship engine that pushes it forward.
Space Journal Entry 2
So in space, instead of pushing back against the ground or the air it kind of pushes back against itself and this makes it move forward.
It's also really important to remember that things can move in 3 dimensions in space and there really isn't such a thing as direction (up, down, left, right). So space travel is going to require propulsion but also a whole new way of looking at the space around me.
Is there gravity in space? On the moon? On Mars?
There is gravity anywhere there is mass! So yes, there's gravity in space, which is what keeps the International Space Station and other satellites in orbit around the Earth, it's just that in space, there's no ground for our feet to press against, so we feel weightless. On the Moon, there is gravity, but the Moon is less massive than the Earth, so the force of gravity is also less on the Moon. Mars is also less massive than the Earth, but more massive than the Moon, so has more gravity than the Moon, but less than the Earth. That means that if you were walking on Mars, you would feel lighter than on the Earth (and would feel the force of gravity less), and you would feel even lighter on the Moon.
Space Journal Entry 3
One important fact to remember for space travel. There is a difference between weight and mass.
Mass is how much is how much matter (or 'stuff') I am made of. Like how much water, bones, muscle, fat and fur I contain. When I step on a scale it says that I "weigh" 13kg but actually it's my mass that's 13kg.
Weight is different though. Weight is how much the force of gravity 'pushes down' on me. It's calcuated using the formula W = m * g (Weight = mass times the force of gravity).
On Earth this is calculated as W = 13 * 9.8 = 127.4
On Mars my weight would be W = 13 * 3.7 = 48.1
On the moon W = 13 * 1.6 = 20.8
And in space you would feel weightless (as there is no ground for you to push against).
So you can see that your mass always remains the same but your weight (or how heavy you feel) changes depending on the gravity of the planet you're on.
I found this neat website that I could use to calcuate my weight on different planets in the solar system that I think is going to be helpful for my space explorations.
You should check out what your weight on different planets would be too!
Could we ever live on the Moon? On Mars? What about other planets or bodies in the solar system?
We could certainly live on the Moon or Mars if we created a base that contained air that we could breath. Unfortunately, the conditions in these places are very inhospitable to humans (and puppies)!
Some other planets and moons in our solar system may have life on them, especially some of the moons of Jupiter and Saturn, but they would not be able to support human life without some sort of self-contained base. The Earth is really the only perfect place that humans can live in the solar system.
What does it mean when they say the “vacuum of space”? Is it true there’s nothing in space?
There are lots of things in space, but they're very far apart! The "vacuum of space" refers to the lack of particles and extremely low pressures in the space between celestial objects. That is, in outer space, there is almost nothing between the stars, planets, moons, and other solid bodies. For example, in interplanetary space, that is, the space between the planets in our solar system, there are only about 11 particles per cubic centimetre, compared to about 100,000 particles per cubic centimetre in the best vacuum that we can create on Earth.
Space Journal Entry 4
First of all was I relieved when Dr. MacDonald clarified that the "vacuum of space" was nothing like the "vacuum of doom" that Pam uses every week to clean up all my hair - that thing is scary!
Secondly I realized that I was going to have to be prepared for space to be very lonely and very empty when I got up there... so I was going to have to take some good books with me to read!
Is there air in space? Can you breath in space? How about on the moon?
There is definitely no air in space, which is why astronauts need to use spacesuits when outside of the Earth's atmosphere or the protection of a spacecraft. The Earth's atmosphere is this thin layer of air that is held to the Earth by its gravity, and is what allows us to breath while on the Earth's surface. The Moon is not massive enough to hold air to its surface, and therefore it doesn't have an atmosphere like the Earth does. That means that when you go visit the moon, you also have to wear a space suit because otherwise you wouldn't be able to breath there!
Space Journal Entry 5
- air tank
I'll also have to remember that air always wants to go where there is more space for it (just like in my bath bubbles) so if I get a leak in my spacesuit the air is going to rush out into space, where there is plenty of room for it.
Better add duct tape to the list!
Is it cold in space? On the Moon? On Mars?
Yes it is! This has to do with the fact that in order to feel heat, you need air or some sort of other medium for the heat to travel through. Temperature is basically a measure of how fast molecules are moving, so if you're in a vacuum, you can't very well measure that heat. On Earth, we feel the heat from the sun, even in the shade, because the air in our atmosphere stores the heat energy. However, in space, there's no air, so this doesn't happen. The moon doesn't have any atmosphere, so the situation is the same there as it would be in the vacuum in space. Mars has a little bit of an atmosphere, which holds some heat, but its atmosphere is about 100 times thinner than it is on Earth. It's also farther away from the Sun, so receives less of the Sun's energy.
Space Journal Entry 6
Make sure spacesuit is WELL insulated!
Actually, this is important for two reasons:
1) it's cold in space
2) because there is air in the spacesuit, and because humans and puppies generate body heat, there will be some heat inside the space suit. But heat, like air, wants to go from where there's lots to where there is little. This means if the spacesuit isn't well insulated any heat I generate will escape into space and not stay and keep me warm. Brr!
Why is space black?
Good question! There's actually an old paradox that asks exactly this question called Olbers' Paradox. The paradox is that if the Universe is infinite, and contains an infinite number of stars, why isn't the sky completely glowing with the light from these stars, which should fill up the entire sky. The solution is that the universe had a beginning! There is probably an infinite number of stars in the Universe, but it takes time for light to travel and so there is light from some stars that hasn't yet reached our eyes. In addition, because the Universe is expanding, the wavelength of the light from the very early universe has increased, which means that even if it once would have been visible with the naked eye, it has now moved out of the range of human sight.
Space Journal Entry 7
This was a tricky one to understand. First I had to look up the word Paradox. I found that it means things that contradict or are opposite of one another. It's a type of logic puzzle where the answer doesn't make complete sense.
Here's one I found:
The second sentence is false. The first sentence is true.
If I look at each sentence on its own they make sense, but put them both together and you get stuck.
So that's why Dr. MacDonald said space being black was a paradox. If there are an infinite (or never ending) number of stars then there should be TONNES of light but there isn't - - it's a contradiction.
It's also kind of neat to think that when you look up in the night sky you are looking at stars that are thousands of light-years away and some of the stars you see may have died thousands of years ago, but the light took that long to reach Earth!
I'll have to remember to leave my sunglasses at home I guess.
How fast does light travel? Can we travel the speed of light (or faster)?
Light travels at approximately 300,000 km/s in a vacuum. Nothing can travel faster than the speed of light according to the laws of gravity discovered by Albert Einstein, called the Theory of General Relativity.
What about time travel? Is that possible?
It's a bit complicated, but theoretically, yes! Einstein's theory of Relativity tells us that if you travel fast enough, close to the speed of light, time slows down for the person travelling. Therefore, if you can reach really high speeds, you can travel to the future faster than you normally would. Travelling back into the past is quite a bit trickier, but if you somehow create a wormhole and then have one end of the wormhole moving very very fast, then it's possible to create a situation where you could travel back to an earlier time. However, you'd never be able to travel back further than when you first created the "time machine".
Also, we don't actually have any way currently of creating a wormhole.
Space Journal Entry 8
So this meant that, if I could find a way to make my spaceship travel really REALLY fast I couldn't go any faster than the speed of light! That also meant that it was going to take me a REALLY long time to get anywhere.
Hmm, for my first trip this wasn't going to be a problem (I just wanted to go to the moon) but later I might want to investigate things like warp drive and wormholes to get me places faster.
I'd also have to investigate time travel later too...
Do you think there is life on other planets?
We've never discovered any life on other planets, but that doesn't mean it's not out there! There are hundreds of billions of stars in our own galaxy, and hundreds of billions of galaxies in the visible Universe. In our own galaxy, we estimate that there are more planets than there are stars, and that approximately 11 billion of these are Earth-like planets orbiting within the habitable zones of Sun-like stars. It seems extremely unlikely that our planet is the only place in the Universe where there is life. However, I also think that it would be very unlikely for us to run into other life in the Universe since the distances between the stars are so vast.
Gee Dr. MacDonald, that was amazing! Now I feel totally prepared to go to space!
No problem Alpha, I was happy to help! Good luck on your trip...
So there I had it, my Space Journal was full of all the info I needed to survive the perils of space; at least for my first trip!
So I grabbed my notebook, pencil and calculator and headed out to the backyard to build my rocket. And just a few weeks later I was ready to go on my grand adventure.
Pam, Fibonacci and Sierpinski came to see me off and I promised I'd be home for dinner. Space travel could be fun but I wasn't about to miss out on Pam's home cooking!
We sure hope you learned a lot about space and space travel and we really want to thank Dr. MacDonald for taking the time to help us out!
If you'd like to learn more check out the interviews she did for CBC Kids:
- 50 years ago, we landed on the moon. Why do we care?
- Wormholes, warp drive and why space travel is so, so hard
And if you happen to be in the Toronto area come check out the AMAZING planetarium shows, telescope viewings and more that she helps run at the Dunlap Institute and the Department of Astronomy and Astrophysics at the University of Toronto (https://universe.utoronto.ca)