Stupid Movie Alert
Astute reader observation: “Well, Keith, at least now when I see a rerun of the old Space: 1999 TV show, I’ll know that more than 24E18 GJ of energy was required to send Moonbase Alpha off into deep space! LOL You have many talented readers.”
David James Elliott to lead ‘Impact’, Hollywood Reporter
“Impact” chronicles the aftermath of a meteor shower during which a piece of a dwarf star lodges itself in the moon. That triggers a series of anomalies on Earth, including cell phone service interruption, exaggerated tides and the occurrence of sporadic weightlessness. Astrophysicist Alex Kinter (Elliott), with a help of a female astronomer, discover that the moon has been dislodged from its orbit and is on a collision course with Earth.”
reader math note: “For what its worth ….. Just a quick note on your stupid movie alert: The minimum delta-V required to put the moon on a collision course with earth is about 4 km/sec. Assuming a lunar mass of 7.348300E+22 kg the kinetic energy equivalent is about 6x 10^14 giga joules. This equates to roughly 1.42 million 100-megaton Fusion warheads exploding simultaneously – and they won’t have long to wait for collision .. about 4 1/2 days.”
Another reader math note: Noticed that the kinetic energy calculations needed to cause a moon-Eartn collision were a bit off. If a delta V change of 4km/sec is needed then the kinetic energy required is 6 x 10^17 trillion Joules (1/2*m*v^2). The number of 100 Megaton weapons required to release this energy is 1.24 trillion.
And yet another reader math note: “For what it’s worth I think the first calc is right 1/2mv^2 = 8*7.34E22 joules = 6E23 joules = 6E14 Gjoules … no? Don’t know how many nukes that is but “a lot” would be a reasonable number …”
And yet still another reader math note: WRT Stupid Movie Alert, some correct physics: Lunar mass is 73.5E21 kg; required deceleration impulse is–on average–809.3 m/s; kinetic energy exchange is thus 24E18 GJ, the equivalent of 57.5E6 100 MT bombs, “a lot.”
The reader math notes keep coming : Here are the kinetic energy calculations: KE = 1/2 m*v^2, KE = 1/2 * 7.35E22 Kg * 4000 m/s * 4000 m/s, KE = 5.9E29 Kg*m^2/s^2, 1 Joule = 1 Kg*m^2/s^2, KE = 5.9E29 Joules
more reader math: Lunar mass is 73.5E21 kg; required deceleration impulse is–on average–809.3 m/s; kinetic energy exchange is thus 24E18 GJ, the equivalent of 57.5E9 100 MT bombs, “a lot more than before.”
