How old is the earth?

How old is the earth?

• I have many many questions,I am not wasteing all my points on them, so if you know them, please just answer the ones you know. How old is the earth? What was the first living thing on earth? what year did dinosaurs die,and do any still live today? how long do you predict until the world ends? what was the first extinct TYPE OF ANIMAL on earth? How deep is the deeepest part of the ocean and how far down into the earth does it go?( like where does it end, outer core inner core crust mantel?)

• Answer:

  ¡Diversión y Juegos! and David D have given some good answers there, I would add a few things. How old is the earth? The exact age of the Earth is debatable, however, the oldest known mineral is zircon from Jack Hills in Western Australia and has been dated to 4.4 billion years old. So you can take that as a minimum. What was the first living thing on earth? Single celled organisms. Stromatolites weren't the first living things, but they were probably the most important of those early life forms, it is believed that they helped oxygenate the atmosphere thereby allowing complex life as we know it to evolve. what year did dinosaurs die,and do any still live today? I would also add that dinosaurs went extinct at the end of the Cretaceous (65Ma) when there was a mass extinction event. More than just the dinosaurs were wiped out, but having said that, many of the biota that existed during the Mesozoic (the time of the dinosaurs which includes the Triassic, Jurassic and Cretaceous) are still in existence today. Crocodiles for example are thought to be around 200 million years old and have clearly survived the K-T extinction event; they're also probably the closest thing we have to dinosaurs today. Controversy exists over the actual cause of the the K-T extinction, some say the Chicxulub impact at the Yucatan Peninsula was the cause of the event, whilst others suggest global climate change was responsible. Perhaps do some research on the K-T extinction event and you can decide for yourself. Also, it is indeed possible that surviving species of dinosaurs evolved into birds, and they do indeed share certain morphological similarities, that said, there's still a great deal of debate over the matter. how long do you predict until the world ends? John W is quite right about the expectations of the sun turing into a red giant, however, long before then it is expected that the Earth will slow down and eventually cease rotating on its axis, this will mean that the Earth will be relentlessly exposed to either the harsh sun on one side, or freezing space on the other - not very good conditions to support life. Of course that's a LONG time away and none of us will have to worry about it. What we should be more concerned with, is not blowing ourselves up in the meantime. what was the first extinct TYPE OF ANIMAL on earth? Very hard one, no one really knows, but it wasn't Trilobites and I'm too lazy to research it to even guess ;-P How deep is the deeepest part of the ocean and how far down into the earth does it go?( like where does it end, outer core inner core crust mantel?) The guys have answered that one very well, nothing to add there :) Hope that helps :-) Angie B.