If you really want disaster on the grand scale, go big. Why bother with the various planets, possible space colonies and bases if the inhabitants are space-faring? Just go whole hog and blow up the star. Can this be done? Umm, …yes, actually, it can. It could even happen by chance, with no intent except the blind malice of the universe.
There are a lot of large numbers here, but cosmic disaster does need big numbers.
Some basic physics and numbers here, then we can get on to blowing shit up. An object falling from infinity to impact will arrive with the surface escape velocity of whatever body it hits. If it hits a star, it will have the surface escape velocity of the star. Its kinetic energy is then given by 1/2 x m x v2.
Good old Sol, our very own personal star, has a mass of 2 x 1030 kg. It radiates 3.83 x 1026 Watts, and it has a surface escape velocity of 6.17 x105 m/sec.
Throw a range of interstellar objects at the star, and what do we get? Take the mass of the impactor, calculate the kinetic energy in joules, dividing by the Earth’s energy output in watts to get seconds equivalent of solar output.
Table 1: Impacts
| Impactor Mass | The Size of | Kinetic Energy | Equivalent to Solar Output |
|---|---|---|---|
| 2.4 x 1019 kg | 16 Psyche | 4.57 x 1030 | 3.3 Hours |
| 9.38 x 1020 | Ceres | 1.79x 1032 | 5.4 days |
| 7.34 x 1022 | Luna | 1.40 x 1034 | 14 Months |
| 3.30 x 1023 | Mercury | 6.28 x 1034 | 5.3 Years |
| 6.42 x 1023 | Mars | 1.22 x 1035 | 10.3 Years |
| 5.97 x 1024 | Earth | 1.14 x 1036 | 95.4 Years |
| 1.00 x 1026 | Neptune | 1.9 x 1037 | 1597.8 Years |
Now, as has been pointed out elsewhere by people who are far better qualified than I am, the probability of such an impact is very low. That is certainly a comforting thought, because a star that does get the golden BB is going to know it, and so will the inhabitants, if any.
Calculating the Effects
Calculating the effects of such impacts is rather tricky. The Sun is a big and dynamic system, and high energy events are common. As I’ve pointed out in another post, a large enough Coronal Mass Ejection that hit Earth could have significant effects on Earth’s orbital and power infrastructure, as in trillions of dollars worth of damage.
The largest solar flare of which there is a record was at least an X28. It may well have been larger, but the sensors on the SOHO satellite maxed out at that point.
An X1 solar flare is approximately 10 ^25^ joules, so we may put the energy of the largest flare we know of at approximately (very approximately) 3 x 10^26^ Joules.
The 16 Psyche impact, as calculated above, would be equivalent to about 39,000 X-class solar flares. It goes on up from there.
Very quickly, the energies involved get to the point where the star would go nova in one fashion or another, and wipe out all life in that star system.
Moving such a planet out of its collision course would require, first, detecting it well in advance, to give warning time for countermeasures, and very large energies.
There are some possible options. Hitting the impactor with another mass, or masses, would change its orbit, though what it would take to move it out of a collision course with the Sun is a calculation I have not attempted. Whether gigaton nuclear bombs detonated nearby, similar to an Orion drive, is something I haven’t calculated, either.
Whether even the Master Blasters are up to that big a Contract, is something I’ll have to look at.
Astronomy. It’s not just cool science and pretty pictures. Its a survival skill.
[…] Species Immortality. A species with a wide range, large population and high technical capability is certainly going to be resilient, being able to absorb heavy losses and meet serious challenges. However great those capabilities, in the scale of the universe they will still be very small. Also, high technology gives the ability to create weapons of tremendous destructive power. Internal conflicts using such weapons could well threaten the entire species. (See my post on Blowing Up Stars) […]