[sevenless]

You can slow down - just that the probe won't remain intact. But perhaps that isn't necessary for the probe to be useful. We can also use these space probes to do geological and atmospheric surveys of the planet when they arrive.

Simply: we slam the probe into the planet, a few milliseconds after it transmits the final images. One gram going at 20% of the speed of light has kinetic energy that bears comparison to the Hiroshima bomb.

At a steep angle of entry, the huge entry glow will give a reading of the atmospheric molecular makeup. And if we can ionize some of the crust, massive space telescopes can get a spectroscopic measurement of the composition, four light years away.

[onion2k]

Let's hope any alien race living there doesn't have the same idea and send a few probes to smash in to Earth.

[sevenless]

That would be like Christopher Columbus, mid-Atlantic crossing, encountering a gunpowder-equipped Mayan navy going off to conquer Europe. Not likely.

[saiya-jin]

now that's a way to say Hi to a foreign species! there isn't high chance this wouldn't be considered as an act of hostility, and if they would check our history of our current world, they would probably just decide to erase this dangerous species from the face of the universe for greater common good.

[sevenless]

I think we both know humanity's interstellar destiny is to become the murderous alien invaders we've faced down in so many movies.