I frequently find myself pondering the scientific veracity of pop songs. I’m a nerd and I love music, so sometimes these worlds collide. It can be interesting to think about, and the investigation itself can be educational – even fun!
For example, consider the song “I Melt with You” by the new wave band Modern English. It was arguably the group’s biggest hit, and it still receives airplay on classic rock radio stations.
The song is not about science at all, yet it contains these notable lyrics:
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I’ll shut out the world and melt with you
Have you noticed the difference?
And it keeps getting better
There’s nothing you and I won’t do
I’ll shut out the world and melt with you
So is this correct? If we stop the planet (let’s say this means stopping Earth’s rotation), will it melt? Amazingly, we can figure it out. The key point here is how much energy it would take to literally stop the world.
The energy of motion is called kinetic energy. You can understand it like this, how much energy should be provided to a huge object to move it at a certain speed. You already have an intuitive feel for it when it comes to familiar objects; Throwing a baseball at 100 kilometers per hour is much easier (takes less energy) than driving a car to the same speed. And, of course, for a given object, the greater the velocity, the more energy is required to get it up to that speed.
Now, this is for linear, straight-line motion. there is also turner Kinetic energy, and again, it’s intuitive: it’s easier to swing a basketball than a car. However, in this case, you also have to consider the size of the object. The larger it is, the greater its rotational energy for a given mass and spin.
Calculating these numbers is not that difficult. ,This could be a high school homework problem.) The real difficulty is in knowing which numbers to use. We have to make a lot of simplifying assumptions otherwise it’s fast becoming a Ph.D. Will change to. Thesis. For example, the Earth is not a solid, homogeneous sphere, but is layered. It has a dense core, a light mantle, and so on, each with a different composition, which affects its total spin energy. Still, we’re not going for exact accuracy here, just a very rough number to see where we stand.
Working through the equations, we find that the Earth’s rotational energy is approximately 200,000,000,000,000,000,000,000,000,000 (2 × 1029) joule, metric unit of energy. One joule is not much – it takes about 300,000 joules to raise one liter of water from room temperature to its boiling point – but 2 × 1029or more than oneoctave Of them, there are a lot.
For comparison, this is roughly the same as our current annual global energy use half a billion years,
That’s energy stored in Earth’s rotation, which was captured during our planet’s formation 4.6 billion years ago. Since physics is generally fine in doing some operations forward or backward, this means that we will also need that much energy. to stop By rotating our planet.
As I see it, this presents two problems. One is how to do it and the other is what happens when you do it.
How Not trivial. This is a fantastic amount of energy. Think of it this way: 66 million years ago an asteroid 10 km wide and several times the size of Mount Everest hit Earth at a speed 20 times faster than a rifle bullet. Its immense kinetic energy was instantly converted into heat, causing a massive explosion that created a 200 km-wide crater, wiping out nonavian dinosaurs and causing a global ecological catastrophe that would take millions of years to recover from. And yet the total energy released in that event was about 1023 Joule, or about ten millionth Earth’s rotational kinetic energy.
In other words, if you want to stop our planet’s orbit by hitting it with asteroids (pun intended) right now To provide maximum braking power), you must perform the dinosaur-killer impact again, then repeat it 999,999 times.
I’m not a biologist, but it seems like this process could be harmful to life on Earth.
But this asteroid solution to our thought experiment brings up a good point: Changing the energy of an object usually makes it hotter. Try stopping a spinning basketball using friction with your hand and it will noticeably warm your skin. By doing this for the Earth, all the heat will rapidly go into the planet itself (and have other significant disastrous consequencesYou can see where this is going.
So how much energy would it take to melt the Earth? This is very difficult to calculate, but happily physicists have done some work. In Encyclopedia of Volcanoes, The energy to melt just the Earth’s mantle – which is actually solid, not liquid – has been shown to be about 3 × 1030 Joule. (Interestingly, it would take about the same amount of energy to melt Earth’s solid inner core.) That’s 10 times more than Earth’s rotational energy, so immediately we have our answer: stopping the world. Will not done Melt it—at least, not completely.
Well, what if we limit it to just the Earth’s crust since that’s where we all live? Making some quick assumptions (like it’s 10 km thick granite rock), I calculated that about 1030 Joules of heating would be required to completely liquefy the crust (Although I have seen some low estimatesTherefore it is difficult for the crust to melt, although it does not follow that the Earth will remain habitable after this; With so much energy absorbed into them, the oceans would easily boil.
Is it possible to destroy the Earth without overheating it? Perhaps, if you do it slowly: for example, you could mount the rocket engines with their business ends facing east, then ignite them. Back-of-the-envelope calculations indicate that the Falcon 9 rocket can generate about a trillion joules of energy, so if you set up a million of them and let them burn continuously for a few million years you could stop the Earth’s rotation. Again, this can lead to some negative environmental impacts (as well as fuel issues). Better check with the appropriate federal regulatory agencies.
Still, perhaps we need to expand what we mean by “stop.” If modern English meant stopping the earth In its orbit around the Sun, How much energy will it take? Actually it is very easy to calculate because we know the mass of the Earth (6 × 10.24 kilograms) and orbital velocity (30,000 meters per second): huge 3 × 1033 Joule. This is not only enough to melt the Earth completely but it is also enough to vaporize it! Literally blow up the world, Death Star-style“only” takes about 1032 Joule, so cooling the planet in its orbital path would actually make our world very, very hot. In that scenario, the song is actually Understanding Case.
Conclusion: Depending on how you interpret the song, you could really melt the world just by stopping by. At the very least, it will cause serious damage – or, as Modern English said in their hit song, “I watched the world collapse on your face.”
I’ve noticed the difference, but it’s definitely No Getting better all the time.
my thanks to my friend michael walter, Director of the Carnegie Science Earth and Planets Laboratory to help melt the Earth’s mantle.
