- The researchers then plugged their figures into astronomy software developed by the US Naval Observatory.
The results suggest the meteor belongs to a well known family of space rocks - known as the Apollo asteroids - that cross Earth's orbit.
A common class of asteroid that comes from the main asteroid belt between Mars and Jupiter in our solar system.
I think the most fascinating part of this story is that the team of scientists used amateur footage to calculate their findings. What a world we live in!
Somewhat agree, as our planet has cleared it's orbit of any debris local to our path around the sun, and that is one of the defining characteristics of a mature planet. But as for objects on eliptical orbits, there are still plenty out there that cross our path that we have not "cleared", there are hundreds of thousands documented. Also, lets not forget that long period objects from the Kuiper belt or even possibly the Oort cloud that may only cross our path on long period orbits once every hundred thousand years or more are still out there. We see and discover new long period objects quite frequently that no living human will ever see again. Not to mention other objects in the asteroid belt, Kuiper belt, and Oort cloud can collide and send stable objects into entirely new orbits. So yes, the VAST majority of objects have already been cleared by our planet, or gobbled up by Sol or Jupiter, but there are still plenty of them out there. And to this day, the Sun and Jupiter take most of the impacts from the objects that do get sent into the inner solar system, but there are still plenty that cross our path. Space is a pretty big place so the odds are low, but there are still risks. So I agree that MOST of them pose no real threat, but wouldn't agree that ALL of the ones left pose no threat. The dinosaur extinction is still linked to an impact of some kind, and that was only 65 million years ago. Granted that seems like a long time, it's really not on the scale of the ~4.6 billion year lifetime of our planet. 65 million years ago the planet was still 4.6 billion years old.
Thank you for this perspective, I don't know much about this topic. In fact I didn't know that this was a defining characteristic of a mature planet. Makes sense.So I agree that MOST of them pose no real threat, but wouldn't agree that ALL of the ones left pose no threat. The dinosaur extinction is still linked to an impact of some kind, and that was only 65 million years ago. Granted that seems like a long time, it's really not on the scale of the ~4.6 billion year lifetime of our planet. 65 million years ago the planet was still 4.6 billion years old.
well said. Awesome perspective.
That's one of the reasons Pluto was removed from planet status, and it's size makes it more of a dwarf planet as well. It was determined to be one of several objects of similar size in the Kuiper belt. Step 3 of the IAU resolution for determining a planet was what I was referencing. http://en.wikipedia.org/wiki/Pluto#2006:_IAU_classification One of the many ways we can search for new planets around other stars is looking for cleared paths of dust/debris. So if we see a disk of dust/debris from UV/IR telescopes, and there's a "path" carved out of it, we can assume there was a larger object, probably a planet, that had cleared it's local orbit even if we can't see the planet itself. Here's a picture of one such example... The disk is at an angle almost going up an down, but you can see the elipse that has been cleared by a possible planet/s.In fact I didn't know that this was a defining characteristic of a mature planet.
The debate came to a head in 2006 with an IAU resolution that created an official definition for the term "planet". According to this resolution, there are three main conditions for an object to be considered a 'planet':
1.The object must be in orbit around the Sun.
2.The object must be massive enough to be a sphere by its own gravitational force. More specifically, its own gravity should pull it into a shape of hydrostatic equilibrium.
3.It must have cleared the neighbourhood around its orbit.
It was a peaceful planet... THEY HAD NO WEAPONS!
Thank you, I've learned a good deal from this post.