Using dummy numbers. But, lets say you need to be going 100mph to escape the suns gravity. The Earth is moving around the sun at 75mph. So you only need to speed up 25mph to leave.
But to fall to the sun, you need to slow down 75mph. And speeding up and slowing down in space take the same amount of energy.
That's how an orbit works. If you think about a low orbit around the Earth, you are constantly falling towards Earth and missing, because you are going so fast around it. Likewise, the Earth is constantly falling towards the Sun, but because it is going sideways so fast it keeps going around instead. You say "aim towards sol" - but in order to do that you effectively need to stop going sideways. Once you have done that, it doesn't matter whether or not you are also travelling towards the Sun - you will be soon. That's what we mean when we say that in order to hit the Sun you need to slow down.
This assumes there is no planet or moon handy to whip around, to end up going in a completely different direction, with no extra energy expenditure.
It is tricky (but possible, with cleverness and a careful schedule) to gain or lose energy this way, but it doesn't matter. If your closest approach is well within the sun's photosphere, it doesn't matter how fast you're going when you get there. So, you can do it with essentially zero delta-v, starting and ending with the same total energy as an object would have co-orbiting with earth, but on an extremely eccentric orbit.
It's not terribly rare (on a geological timeline, at least) for comets to dispose of themselves this way.
Anyway, what is so great about dropping them in the sun? Jupiter swallows comets frequently. Mars is a squalid dump, and so is Venus, at least below the clouds.
Great explanation. I think many people have the wrong default intuition for what an orbit is. I don't think they realize that it means going so fast that you fall perpetually around an object rather than just eventually hitting the object.
The radius of Sol's gravitational influence is much larger than the radius of its coherent mass.
The sun is always at one focus of the elliptical orbit. You just can't get the orbit close enough to plasma-brake near perihelion without also pushing your aphelion way out. So you have to aim away from Sol in order to get there at lower energy. Basically, a Voyager probe that stops at the very edge of the gravity well and then plunges straight down. Spiraling down while decelerating is faster, but costs more energy. But as you get closer, you can harvest energy from the solar wind and solar radiation, with solar sails, so the amount of delta-v you have to load onto the launch rocket does not represent your entire delta-v budget.
There are ways to trade off time for delta-v, but at that scale, the ways that really make a difference mean that the person that sets them in motion will be ancient or dead before they finish.
Maintaining a supply of spare parts for a line of notebooks could very well use more natural resources than maintaining a supply of working laptops for replacement.
Your logic works if you only are going to listen to a song a few times, but after a certain threshold, the artist would receive more money than from a CD or iTunes purchase.
I don't think there is anything wrong with an email provider asking me for my cell number to send me text messages, how else would they send them?
In addition, a cell phone number is NOT required to create a Google account. Sure they ask (and gender is apparently required, I just made an account), but if you leave it blank, they won't complain.
There is nothing wrong with providers giving you an option to use your number for notifications. However, if we are required to provide phone number for security features that can be implemented without using phones, there are a few things wrong with it.
How can this be implemented without using a phone number? Well, the article actually contains one way - pre-shared secret codes that you print out beforehand. There are many others.
Would you care to elaborate how you'll be able to power a drone for an extended amount of time? I was doing some minor research (I was curious about the pirate bays 'server drone' idea), and the best that I could personally come up with was flight times of about an hour. That doesn't seem all that useful to maintain a constant server, or traffic cam, presence.
For the traffic cam application, where people aren't trying to shoot it down, it would be pretty simple to switch it out regularly with one from a nearby charging station. You might even be able to use a balloon to take off a lot of the weight, so you can just use the rotors for altitude adjustment. You'd be slower, but would probably last a lot longer.
I wonder if anyone is looking at a hydrogen balloon/drone hybrid. Small so it's not a Hindenburg bomb, lots of failsafe, but the power/lift ratios might give it a significant mission duration.
The same way they do satellite coverage at non-geostationary orbits: You have a group of drones that swap in and out. Depending on how far/how long it takes to refuel and get a drone back into the air, you could provide continuous coverage of a single area with as little as 2-3 drones.
But to fall to the sun, you need to slow down 75mph. And speeding up and slowing down in space take the same amount of energy.