Every so often it’s fun to check whether romantic pop lyrics survive scientific scrutiny. Modern English’s 1980s hit "I Melt with You" offers a dramatic line that begs the question: if you could "stop the world," would the planet literally melt?
"I’ll stop the world and melt with you
You’ve seen the difference
And it’s getting better all the time
There’s nothing you and I won’t do
I’ll stop the world and melt with you"
Surprisingly, basic physics lets us make a useful estimate. The relevant quantity is kinetic energy: for rotation, rotational kinetic energy is the energy tied up in a spinning body. Using standard approximations for Earth, its rotational kinetic energy is on the order of 2 × 1029 joules—a colossal amount by everyday standards (remember: ~3 × 105 J boils a liter of water), but modest compared with the energy required to melt the planet.
How Much Energy to Melt the Planet?
Geophysical estimates put the energy required to melt Earth’s mantle at roughly 3 × 1030 joules—and melting the solid inner core would require a comparable amount. That is more than an order of magnitude greater than Earth’s rotational energy, so merely halting the planet’s spin would not supply enough energy to liquefy the whole interior.
If we narrow our target to the crust—the shell where we live—simple estimates (e.g., a ~10 km thick granite layer) suggest on the order of 1030 joules would be needed to melt it completely. Even if despinning fell short of fully melting the crust, dumping anywhere near that energy into the system would boil the oceans and wipe out surface habitability.
Putting Those Numbers in Context
Consider the asteroid impact that ended the age of nonavian dinosaurs ~66 million years ago: that event released roughly 1023 joules, carved a ~200 km crater, and caused a global ecological catastrophe. That is about a millionth of Earth’s rotational kinetic energy. To stop the planet by repeating similar impacts (optimally aimed) would require roughly a million such collisions—clearly incompatible with sustained complex life.
Energy changes almost always produce heat. Friction or dissipation that removes rotational energy tends to end up as thermal energy: rub a spinning basketball and your hand warms. Applied to Earth, most of the removed rotational energy would be converted into heat, leading to severe heating of the crust, oceans, and atmosphere.
Could You Do It Slowly?
In principle, despinning slowly could mitigate an immediate temperature spike. As a thought experiment, if you installed huge braking thrust—imagine millions of rocket stages oriented to oppose Earth's rotation and burning for millions of years—you could bleed off rotation gradually. A rough back-of-the-envelope figure: a Falcon 9–class rocket burn corresponds to ~1012 joules of output, so a million such rockets running for millions of years could, in theory, reduce rotation. Practically, however, fuel requirements, environmental consequences, material limits, and governance make this effectively impossible.
What If "Stop the World" Means Stopping Earth's Orbit?
If instead you halted Earth’s orbital motion around the Sun, the energy scale jumps dramatically. Removing Earth’s orbital kinetic energy (~mass × velocity²/2 with mass ≈ 6 × 1024 kg and orbital speed ≈ 30,000 m/s) requires roughly 3 × 1033 joules. That is more than enough to melt and likely vaporize the planet—comparable to or exceeding crude estimates for the energy needed to disrupt the planet (~1032 J).
Bottom Line
Interpretations vary, but the facts are clear: stopping Earth’s rotation would be catastrophic and could boil away oceans and wreck habitability, yet it likely would not melt the entire mantle or core. Stopping Earth’s orbit, however, would release vastly more energy and would probably melt and vaporize the planet. So, depending on interpretation, the lyric is either dramatic but physically overstated (despinning) or an understatement (stopping orbital motion).
Acknowledgment: Thanks to Michael Walter, director of the Carnegie Science Earth & Planets Laboratory, for help with mantle-melting estimates.
