Hacker News Reader

No, false.

More or less today’s technology could not accelerate tungsten to speeds that would obliterate a planet.

And you say it’s trivial? Who told you this?

Just run some calculations it doesn’t make sense.

(just one example, 10,000lbs of tungsten hitting the earth at 99% of light speed would not destroy it)

——

it is trivial for us to end their civilization. If we decided to, with more or less today’s technology, we could accelerate a chunk of tungsten to comical speeds and obliterate their homeworld. It would cost a fortune and it would take awhile, but we could do it.

Not to mention the difficulty of hitting a planet-sized target at 99% of the speed of light from 5 light-years away. I'm pretty sure this would be vastly more difficult than anything we've ever accomplished as a species.

Plus with those same resources you could probably build a solar-system-sized passive interferometric radar swarm, and get decent warning time on any relativistic launches.

0.99c of blueshift coming from a specific star's direction? Weird. Shoot a couple relatively slow BBs at it, and the projectile will vaporize itself around the Kuiper Belt.

Poor guys. They've now announced to the universe that they're an aggressive threat to all life around them…

> 10,000lbs of tungsten hitting the earth at 99% of light speed would not destroy it

I mean, the planet would exist, but it wouldn’t exactly be capable of sustaining life any more.

No, also false.

And my example was only 99% light speed.

At the link below you can see simulations at 99.9% light speed. An entire Egyptian pyramid, hitting Earth at this 10x higher speed, might kill off life, but it’s still not obliterating the planet.

We are not capable of accelerating any macroscopic object to .999C. Let alone a huge piece of tungsten, which still wouldn’t be powerful enough.

https://youtu.be/DwgMjr-Qu1Y?si=-goF8QResb976kpN

That's like 0.003X of a Chicxulub impacter. Or around 1X the geologically very recent eruption of Mount Toba.

The ecosphere will be fine. You'll probably vaporize a small patch of ocean, and they'll get colorful sunsets for a couple days. But that's about it.

By contrast, assuming "more or less today's technology", we're now out of petroleum reserves because we used them all in our magic instant-acceleration kinetic-energy-converter.

With our current technology, it isn't possible for us to accelerate any amount of tungsten to relativistic speeds except for a few atoms in particle accelerator. The rocket equation means needs ludicrous amounts of fuel to reach relativistic speeds.

This includes near-term technology like fusion reactors. You could take Jupiter along for fuel but still not reaching 99% of light speed. For stationary launchers, they would be super long or require enormous amounts of energy. Giant arrays of lasers aren't "possible with current technology".

Relativistic projectiles probably requires antimatter. Which are pretty far beyond our technology. There is big question is antimatter rockets are possible, they require producing and containing a lot of antimatter. Although, it instead of accelerating super fast, it is probably easier to send the antimatter.

In this hypothetical scenario, we wouldn't know if they have known of our existence for a long time, and maybe even taken precautions like installing some proxy killer probes in case we had a stupid crazy idea like trying to launch a genocidal relativistic missile against them.

So, why would we go so blindly for option 3 and risk it all by being the first ones to defect in an interstellar prisoner's dilemma? Especially if we have good reasons to suspect that they've known about us for long and have remained neutral so far. After all, Proxima Centauri is quite close, and our atmosphere gives ample signals of there being life here. And we haven't been particularly quiet either.

I haven't delved deep into this, so there might be some much more tight logic to it. But my first impression is that the dark forest hypothesis seems a bit forced; sort of constructed backwards in order to explain a cool idea (that space is full of civilizations but everyone is quiet).

For example, one of the assumptions it makes is that obliterating another space-faring civilization is easy. And, at the same time, that we (and everyone) have very little information of other civilizations. I don't see how these two assumptions can hold at the same time.

These scenarios are so funny because they’re totally focused on threats and destruction as the key assumptions, and then they invariably conclude “so we should destroy them”.

And it’s just like, that’s such a colonizer mentality, trying to game out a completely unknown society and immediately focusing on threats, technology, and destruction.

I wonder, what are they like? What could we learn from them? Why are we assuming all beings are violent like us? Does it really make sense to immediately obliterate a culture you’ve never even seen? I seriously doubt it. You could send probes, spies, and try to covertly learn about them. You could send envoys, without revealing your origin, and try to gain knowledge from first contact. You may learn there is no threat, and a great deal to be discovered.

What if they had medicine which could cure every disease? Energy generators which could save our planet? What if they were simply peaceful beings with a rich beautiful history, and no desire or capacity to harm us?

The threat/destruction paradigm feels so simplistic, impoverished, and brutal.

> I wonder, what are they like? What could we learn from them?

Of course I wonder these same things. But when the consequences of becoming known to the wrong civilization are inevitable destruction, what are your alternatives?

We very nearly killed ourselves (we still might!) with nuclear weapons because we thought the other side might shoot first. This is that taken to an even further extreme: we won’t even know if we’ve been shot at until it’s far too late to do anything about it. We likely wouldn’t ever even know who sent the damn thing in the first place.

The balance of things is that silent civilizations with caveman-level technology are more than capable of wiping out noisy and naïve technologically-advanced civilizations.

You can wonder all you like about who and what these beings are and what wonders they must know of, and absolutely none of that will matter when a tungsten rod turns the planet into a fireball because you made the mistake of sending up a signal flare without having any idea that it was safe to do so.

One in a thousand civilizations could be paranoid enough to sterilize other spacefaring civilizations and it would be reason enough to be very, very quiet.

> when the consequences of becoming known to the wrong civilization are inevitable destruction

This is the presupposition that seems entirely baseless to me. An explanation has been constructed that comes to this as the only conclusion, but the assumptions in the explanation seem themselves to come from nothing. I think this is what often called "projection". Human beings are a violent creature that destroys others, so we assume these alien creatures must be. But they are aliens. We presently know nothing about aliens. My view is that we should interrogate the assumptions that lead us to your brutal conclusion. Projection of our own fears is insufficient to make the right choice.

Another question to reflect on: Why do you not destroy every person you come in contact with? They could likely kill you if they tried. But more so than legal consequences, you simply feel no desire to do so. There are reasons for your feeling that way.

If you believe in dark forest, it's not one in a thousand, even benevolent civilizations have a reason to genocide you, because you would shoot them indiscriminately.

> It would cost a fortune and it would take awhile, but we could do it. Certainly it would be orders of magnitude easier than getting humans there, setting up any sort of interstellar trade, or working to understand each other’s language and culture. And nobody at the receiving end would be the wiser until their planet essentially ceased to exist one day.

Many of these arguments seem to work equally well for France nuking Britain.

I am also skeptical of any overly pessimistic alien interaction theories, but I don't think this analogy applies here. We already have open communication channels and centuries of trust between the British and French, and we certainly did pillage each other before we figured out how to speak to each other.

But you did learn how to speak to each other, and you're stronger together now than you ever were apart.

> Meanwhile, it is trivial for us to end their civilization. If we decided to, with more or less today’s technology, we could accelerate a chunk of tungsten to comical speeds and obliterate their homeworld.

We wipe out their planets, then the 99% of their civilisation that isn't living on planets wipes out our planets. Now we have two very angry civilisations (without planets) in a protracted interstellar war. Great.

Specify a current technology that could accelerate to 99% light speed. Heck, specify future technology that we could conceivably build. Now, what is the exhaust velocity? What is the mass ratio for the starship? How big is that compared to mass of the entire solar system?

How is that energy expenditure going to be not noticeable to aliens?

Option 3 doesn't work if they have a decoy planet to catch hostile attackers.

PBS Space Time discussed these 3 options and more recently.

4. If they didn't notice anything, we can wait more and send them a spy probe to learn their culture. If they are mad foresters, we might genocide them, but if they aren't, it's not more dangerous than having France with nuclear weapons. Under this strategy only foresters get what they want :)