 This is Brad here at ANU and we hear a lot about exploring the solar system and going to different planets but it's not as simple as that. It takes time. Jamie here is going to chat with Adam and Liz about how actually we explore our solar system. Thanks Brad. So today I'm here to talk to you basically about the distances in our solar system and why that helps us or hinders us when we're trying to explore. So first we have our nice son here. Hi son. Hello son. You're looking shiny today. So we'll just place this son here in the center of our solar system and you Liz you're looking down to earth today. How would you like to be on earth? Perfect. Great. So do you know the distance between yourself and the sun? No, no idea. No idea. It's a massive distance. It's 150 million kilometers away between the sun and you Liz which is really big distance considering the light from the sun only travels at 300,000 kilometers per second to get to you. It's really fast. Very fast. So given that we know that the distance between the sun and you Liz is 150 million kilometers and the light from the sun travels at 300,000 kilometers per second. How long do you reckon it would take the sun to get from the light from the sun to get from the sun to you? My brain cannot compute that but maybe a couple of minutes. Yes that's a very close answer so it takes eight minutes for the light to travel from the sun to you. So for example if the sun was to disappear we wouldn't realize it for eight minutes which is a really long time. So that's very well and good for the earth but what about another planet say Mars jammy? I knew you'd bring that up Adam since with everybody wants to go to Mars these days but what distance do you reckon you is between Lizh on earth and you on Mars? It would have to be tens of millions of kilometers but I really don't know. Yeah but that is really good you're in the neighborhood it's an additional 75 million kilometers between Lizh on earth and you on Mars. So for example if we use roughly the sun, Lizh is there, they knew Adam slightly a bit more that's roughly the distance okay maybe slightly closer yes. So half the distance again? Half the distance and since we know it's half the distance and light travels it light takes eight minutes to travel from the sun to you Lizh it will just take another four minutes to travel to you Adam. All right so but this isn't the only way the planets are arranged in the solar system for example as the planets rotate around the solar system so Adam you for example rotate nice and easily on the other side of the solar system you're a lot further now so knowing that the sun and Lizh you're still at 150 million kilometers but Adam has now moved all the way to the other side do we know the distance between you Lizh and you Adam? Be a lot further hundreds of millions of kilometers or so yeah so that's right so 450 million kilometers between you guys now and say you were trying to have a video call so Adam if you could just wave to Lizh all the way. I'm getting nothing. You're getting nothing basically you have to wait for 24 minutes before something happens something arrives because of the massive distances and to show this today we have a nice little RC car so we'll just pretend here you go Adam to put on Mars. I love a new toy shall I turn it on. Yes that's a very good idea and then Lizh a remote to control the car we just switch it on so give it a go oh no nothing's happening. Broken. Broken or maybe it's the distance between them. Ah because it's going to take a long time for this signal to get all the wiped Mars where Adam is. Exactly. To power it. 24 minutes. 24 minutes exactly what should we do? Whoa what was that? Oh I guess 24 minutes must have passed. Geez we can really see that even going just from Earth to Mars it's a really long distance and so this signal delay is why we need things such as the curiosity rover on Mars and this is also why as we go further away from Earth these kind of things become harder and harder.