120 replies to this topic

[Russ]

That's it... Now you guys are starting to catch on.

I understand your frustatration. I know what it's like to be ingnored by everyone. Which is why I should probably stop ignoring you.

[Siguy]

It's not that people are ignoring me. I'm used to that. What annoys me is the lack of public knowledge about astronomy and just general ignorance.

[Russ]

What annoys me is the lack of public knowledge about astronomy and just general ignorance.

Then you're probably going to be annoyed for your whole life. It seems like nobody cares about science anymore.

[CastChaos]

It's not that people are ignoring me. I'm used to that. What annoys me is the lack of public knowledge about astronomy and just general ignorance.

Well, astronomy isn't something that people learn in good detail, even not in countries where people actually learn something in school...
But feel free to explain in deep detail how this thing would work... Is it possible for a planet to came? Why? Why not? What about bombing a meteor? Why? Why not?
Note that nor a weblink, neither a "this is just simply stupid" sentence solves the case.

As for science... well, I'm interested in new science inventions and discoveries, but not in the thing that is called "science".

[sigtau]

Seriously, I'm not going to believe it's coming until I get some physical proof here. Asking for that isn't my thing, but in this case it's something I need to truly start believing there's some random planet hurtling through space at an inertia rate of God-knows-what towards Earth.

[trucky5]

Yeah seriously and if some random thing was coming towards Earth, it would have to deal with a bunch of other planets and rubble and whatever before it got to Earth so it's like really unlikely! NASA did say that it could happen if the planet were orbiting one of our stars but still they said it was being done in other solar systems

[Siguy]

Well, astronomy isn't something that people learn in good detail, even not in countries where people actually learn something in school...
But feel free to explain in deep detail how this thing would work... Is it possible for a planet to came? Why? Why not? What about bombing a meteor? Why? Why not?
Note that nor a weblink, neither a "this is just simply stupid" sentence solves the case.

As for science... well, I'm interested in new science inventions and discoveries, but not in the thing that is called "science".

Well, first of all, "meteor" is incorrect terminology. Meteor is short for "meteoroid". A meteor is a small particle that burns up in the atmosphere without causing impact. Meteor showers are caused by Earth passing through clouds debris left by comets. Comets are icy bodies that orbit the sun and can cause a spectacular show when they either vent out gas (like Comet Holmes did) or reach perhilion, which is their closest approach to the sun. They always have two tails, one is dust and debris left by the comet, and the other gases. The tails point away from the sun no matter which direction the comet is moving, due to radiation pressure.

A meteorite is a rocky or metallic object which actually impacts the Earth's surface.

What I believe you're thinking of is an asteroid. An asteroid is a minor planet usually composed of metal or rock that orbits the sun and is a few kilometers across. The largest asteroid is Ceres (but it has now been classified as a "dwarf planet" along with Pluto and Eris, so I should probably say "the largest object in the asteroid belt.") Ceres is round and about 950 km. across. It has no chance whatsoever of impacting Earth, as it is in the asteroid belt. The asteroid belt refers to a region of distance from the sun between Mars and Jupiter. It contains most known asteroids. A horriby incorrect popular representation of the asteroid belt is it looking somewhat like the "asteroid field" in Star Wars. In reality, though there hundreds of thousands of thousands of main belt asteroids, since it is such a huge area, there is a huge amount of space between asteroids and it is extremely rare for them to collide with each other.

All main belt asteroids cannot impact Earth. They are much too far away. But there are hundreds of known "near earth asteroids" which are asteroids that orbit at the same distance from the sun as Earth. Some can collide with Earth. Apophis was an asteroid that caused a brief scare a few years back when there was a high probability of impact with Earth. But now the probability is extremely low, not significant at all.

Every once in a while there's a brief scare after a new near Earth asteroid is found that shows a high probability of impact, but usually the data is refigured and the possibility of collision is ruled out.

Comets can also collide with Earth. It is believed that comets were involved in panspermia, or at least delivering amino acids essential to life as we know it. I will not go into that as I do not know much about it. Jupiter, with it's huge mass, helps shield Earth by directing comets away from the inner solar system. The breakup and subsequent collision of Comet Shoemaker-Levy 9 with Jupiter is a perfect demonstration of that.

There are billions and billions of comets yet to be discovered. Leftovers from the formation of the solar system, they have highly eccentric orbits which bring them to practically touch the sun, to almost as much as a light year out. There is a distant "cloud" of billions of comets known as the "Oort Cloud" which is like an asteroid field for comets. Once again, the space is huge, exponentially larger than than the space in the asteroid belt, so it is not an actual cloud. Long period comets come from the Oort Cloud and travel into the inner solar system. They do not return to the inner solar system for thousands of years. Examples of famous long period comets are Comet McNaught, and Comet Hale-Bopp. Also, basically every "great comet" in recorded history that wasn't Comet Halley was a long period comet. Short period comets, or periodic comets, orbit closer than the Oort Cloud and have a certainty of returning in the near future after they have entered the inner solar system, usually within a human lifespan. Comet Halley (NOT "Halley's Comet", the proper way to say a comet's name is to say the word "comet" before a person's name) is a famous periodic comet which returns every 76 or so years. It is the only periodic comet with the possibility of being a "great comet". It's 1986 approach was rather disappointing, though.

Blowing up a comet or asteroid with nuclear explosives is about the worst way to get rid of a possible impactor. (I wouldn't put it past some of our current world leaders, though. )

First of all, it would be very hard to do. Imagine a three kilometer (or something) wide iron-nickel asteroid hurtling towards Earth. I am not good at advanced mathematics so I cannot estimate the mass. Anyway, this is a chunk of metal the size of manhattan. (well, probably not, but I don't know these figures so once again, it's huge.) You just can't blow it up. Try bombarding it with all the nukes in your arsenal. It won't be destroyed. Even if you somehow managed to plant a nuke larger than any bomb ever made* before dead in the center of the asteroid, it would then blow up and you would have thousands of chunks of radiation-contaminated metal hurtling towards earth. I'd personally take the initial impactor.

I guess you could get your inconcievable super-nuke and explode it on one side of the asteroid, slightly changing it's orbit, but that would be really, really, inefficient. You'd probably have to bombard it continuously, costing ridiculous amounts of money.

The most practical way of preventing an asteroid from impacting Earth is by using a "gravitational tractor" to fly next to the asteroid and slowly change its orbit over the course of a few years by tugging on it with its own gravity. This seems like a small difference, but when talking about the distances in space, a tiny change makes a big difference in the long run.

*The largest bomb ever made was the 60 megaton Tsar Bomba/Big Ivan thermonuclear bomb built by the Soviet Union in the sixties. It was designed to be 100 megatons, but that would have been too huge. It was the size of a school bus and couldn't fit completely in the bomb bay of the largest Soviet bomber there was. It exploded a few kilometers above Novaya Zemlya. The shockwave shattered windows in Finland. You could feel earth move beneath your feet on the other side of the world, on the shockwave's third pass around the world. For a few nanoseconds it produced as much energy as the sun. Tell me that isn't huge.

I am tired of typing now so I will talk more later.

[sigtau]

Disclaimer: THERE IS NO PLANET NIBIRU. When it hits Earth and I die first (that is, IF it does) then you can laugh all you like, but I'm being skeptic here. I swear, who made this up?

[CastChaos]

Hey Siguy, that was useful. It contained some information new to me.

TMS: I'm still not 100% convinced that "Nibiru" is in fact a name of "Jupiter". After all, the Celtic temple I was talking about showed Jupiter AND Nibiru. But of course it won't come here, a planet can't fit through the planets and asteroid belts to reach Earth. Unless all planets were at the other side of the sun at that time, but still... I know a whole planet won't come.

[Siguy]

...planet can't fit through the planets and asteroid belts to reach Earth. Unless all planets were at the other side of the sun at that time...

What do you mean by that?

[CastChaos]

What do you mean by that?

Well, while the planet comes from outer place towards Earth, it surely either collides into another planet (most probably Jupiter) or collides with so many asteroids that big shards keep collapsing from it until it becomes a pack of asteroids, itself. Unless if... imagine a map of the solar system. Imagine that all planets line up. Earth is one end of the line and then come the others. This way (even without perfect lining) a rogue planet could reach Earth... if it weren't for the asteroid belts.
However, I keep forgetting that the world is 3D, not a sheet of paper... a rogue planet could come from not only in the line of the solar system. Unless the solar system is orb shaped, not circle as I always imagined...

But rogue planets aren't too possible, not? How a planet could leave it's solar system? Even if a small asteroid collides into it, that would change its orbit, not? Unless the planet is created outside a solar system, without the compiler power of a sun.

I still remember the first time when I learned about Earth being round. I was about 3-4 years old, my father brought it up as a random subject. I easily believed this space thing, but it required time til I understood that each planet has it's own gravity instead of Earth being the ultimate center...

[LostInHyru1e]

I don't think I've posted here yet...

This "Nibiru" is a load of crap, in my opinion. It might have been more believeable if they didn't make up obviously disprovable things like that if you live in Australia you'll see it "Clear as day, 1/4 the size of the sun."

[Rocksfan13]

What do you mean by that?

I think he means that since most of the planets are behind us and not on the opposite side of the sun.

Sorta like this:

[CastChaos]

^Yes, that picture clearly shows what I meant. If a planet comes from the upper right (on the picture), its way is clear from other planets. Just less shelter.

[Siguy]

Well, while the planet comes from outer place towards Earth, it surely either collides into another planet (most probably Jupiter) or collides with so many asteroids that big shards keep collapsing from it until it becomes a pack of asteroids, itself. Unless if... imagine a map of the solar system. Imagine that all planets line up. Earth is one end of the line and then come the others. This way (even without perfect lining) a rogue planet could reach Earth... if it weren't for the asteroid belts.
However, I keep forgetting that the world is 3D, not a sheet of paper... a rogue planet could come from not only in the line of the solar system. Unless the solar system is orb shaped, not circle as I always imagined...

But rogue planets aren't too possible, not? How a planet could leave it's solar system? Even if a small asteroid collides into it, that would change its orbit, not? Unless the planet is created outside a solar system, without the compiler power of a sun.

I still remember the first time when I learned about Earth being round. I was about 3-4 years old, my father brought it up as a random subject. I easily believed this space thing, but it required time til I understood that each planet has it's own gravity instead of Earth being the ultimate center...

You just contradicted almost everything I said. Space is big. Planets are small. Asteroids are even smaller. They are far apart. The asteroid belt is NOT thick with asteroids. It is not an actual physical object. It is just a region of distance from the sun where most asteroids are found.

Though planets and most objects that orbit the sun orbit on the plane of the solar system, known as the ecliptic, there are many objects, mostly smaller ones like comets, that orbit inclined to the ecliptic.