00:00It may seem like the best way to get to some planet from Earth is to patiently wait for it to
00:04come as close as possible. Yeah, there it is. And then take off on a rocket pointed in the
00:10planet's direction. Whoa, bye mom, see ya! Wait, why didn't this method work?
00:18First off, the planets, including our own, constantly move following their elliptical
00:23orbits at speeds of tens of miles per second. So your rocket kinda needs to be put in an
00:29elliptical orbit, right? Kinda like aiming a dart at a moving target or throwing a
00:35surprise party for your friend. You don't want the surprise to come at the wrong moment.
00:42Also, when we send spacecraft to other planets, we want to use as little energy as possible.
00:48And to get to any planet out there in the easiest way possible,
00:51you actually need a special trick called the Hohmann Transfer Orbit.
00:56Let's say you want to travel to Mars. You have to wait until Earth and the red planet are in
01:01the right positions so you don't get lost up there or run out of fuel somewhere halfway.
01:07Travelling there using a Hohmann Transfer Orbit would take about 259 days. That's because the
01:13transfer orbit between Earth and Mars takes 517 days to complete a full orbit,
01:19and the trip to Mars covers half of that orbit.
01:22Couldn't you just travel faster? Well, yeah, but that would waste way more fuel,
01:27which would make the launch more complicated, since the rocket would be too heavy. Basically,
01:33it would be like a dog biting its own tail. If you could travel at the speed of light,
01:38it would take you 12.5 minutes. Also, when your rocket finally gets to the other planet,
01:45it still needs to slow down to go into orbit, so you don't have to worry about getting lost.
01:52Or even land on its surface. This means it will use more energy, but you can try to use as little
01:59as possible and maybe go with things such as parachutes or aerodynamic braking. It's kind
02:05of like if you were riding your skateboard and needed to stop. You wouldn't just crash into a
02:09wall. You'd use your foot or something to slow down gradually. Traveling to Venus is a bit quicker.
02:18It would take you about 146 days. That's not bad, but the problem is you'd still need to wait for
02:25about two years before coming back to Earth. That's necessary because the planets need to
02:30realign themselves properly so that the spacecraft can meet Earth's orbit when it returns. So,
02:36in total, a round trip to Venus would take around two years and one month,
02:41including the waiting time. And that waiting time wouldn't be that pleasant, considering that's the
02:47hottest planet in our solar system. Let's say you want to travel to Jupiter. How long will that take?
02:55It depends on a lot of things, mainly its position. Plus, how fast are you traveling?
03:01If you want to use the best technology we have right now, you should know that it took the
03:05fastest spacecraft ever built, NASA's New Horizons, just over a year to reach Jupiter.
03:12But keep in mind that the New Horizons mission was just a flyby. The spacecraft didn't actually go
03:18into orbit around Jupiter. If you wanted to stay in orbit and explore Jupiter up close,
03:24it would take way longer. So, definitely not a weekend trip.
03:31Using the Hohmann transfer, you'd need several years to get to Jupiter. That's because a Hohmann
03:37transfer puts focus on transferring an object from one orbit to another. Jupiter is in a higher orbit
03:43than our home planet. So, to finish the transfer, your rocket would need to travel along a path
03:49that would take it past the orbit of our gas giant. So, the rocket would need to speed up
03:54when it gets closer to Jupiter to avoid falling back towards the Sun, and then slow down when it
04:00passes Jupiter to avoid flying off into space. It's like a car speeding up to climb a hill
04:06and then slowing down as it goes down the other side. This is how the spacecraft
04:10uses the gravity of Jupiter to move into orbit around the gas giant.
04:17It's hard to tell the exact distance between Jupiter and Earth. They're both traveling around
04:21the Sun in different oval-shaped paths. Sometimes they get really close to each other, and other
04:27times they're really far apart. It's like they're playing tag. But on average, they're 444 million
04:34miles away from each other. When Jupiter is farthest away from Earth, it's a whopping 601
04:40million miles away. That's like driving around the entire Earth 24,000 times. But if you could
04:47travel to Jupiter at the speed of light, on average, you'd get there in 40 minutes.
04:54There's this super-fast spacecraft we need to mention, the Parker Solar Probe. Imagine you're
05:00on a really fast roller coaster, moving at incredible speeds that are hard to fathom.
05:05The roller coaster would actually be our Parker Solar Probe.
05:09It's flying closer and closer to the Sun, breaking speed records along the way.
05:16During its 10th close flyby of the Sun in November 2021, the Parker Solar Probe
05:22managed to reach a top speed of more than 360,000 miles per hour. That's like traveling
05:28around the whole Earth in several minutes. And get this, when the spacecraft gets even closer
05:34to the Sun in December 2024, it's expected to reach a speed of 430,000 miles per hour.
05:41Yep, not a good idea to have a big lunch before this roller coaster.
05:47Now, let's say you're on the Parker Solar Probe and you want to take a detour to visit Jupiter.
05:53If you were able to travel in a straight line at the same speed the Parker Solar Probe was going
05:58during its 10th flyby, it would only take you 42 days to reach Jupiter at its closest approach.
06:04On their average distance, you'd need a little bit longer to get there, 51 days.
06:11You'd also have to consider the duration of your trip.
06:14There are two ways your rocket can arrive at a planet, either by going into orbit around the
06:19planet or by just flying by really fast. If the spacecraft is supposed to go into orbit,
06:25it needs to slow down when it gets close to the planet. Imagine it gets captured by the
06:30planet's gravity and starts going around it. Better to slow it down when it arrives then.
06:35And this means burning lots of extra fuel and making your trip longer.
06:41Here's something interesting. To travel faster, we can use something called gravity assist.
06:47That means we use the gravity of planets and other objects in space to give us a little push and
06:53speed our precious rocket up. That's how the Voyager spacecraft were able to travel to Saturn
06:59and beyond. But even with a gravity assist, it still takes a really long time to travel to other
07:06stars. For example, the star that's closest to us is Proxima Centauri, and it's still 4.2 light-years
07:13away. Let's change the method now compared to the previous examples. If we traveled at the same
07:19speed as Voyager 1, it would take us 75,000 years to get there. If you prefer to take a trip to
07:27Uranus, know that the distance goes up to 2 billion miles, depending on the spot where the
07:33planets are during their orbits. It took about 9.5 years for Voyager 2 to reach Uranus.
07:41But Uranus is cold, and as an ice giant, it doesn't even have a real surface to land on.
07:47Most of the planet is swirling fluids anyway. Not only would you have nowhere to land there,
07:52but your rocket would hardly even manage to pass through the atmosphere of Uranus unscathed.
07:58The temperatures and pressures are extreme up there, and would just destroy your entire metal
08:03spacecraft. That's it for today. So hey, if you pacified your curiosity, then give the video a
08:11like and share it with your friends. Or if you want more, just click on these videos and stay
08:16on the Bright Side!
Comments