If the Earth is 4.5 billion years old and humans have only been around for a few hundred thousand years, how do we know there have not been many more civilizations and species before us?
The Universe is 13.7B years old. The Earth has not existed since the moment the Universe was created and is about 4.5B years old and is made out the debris of two previous generation of stars.Life on Earth started shortly after the temperatures cooled down, about 3.7B years ago. Up until 600M years ago, life was predominantly single-celled organisms. From 600M years until now, the variety of life that we see evolved.Humans started to separate from the rest of the great apes about 7M years ago and we became modern humans 200k years ago.Life has immense complexity and we don't see species arising multiple times. It's just incredibly unlikely. Like a [math]10^{-500}[/math] chance -- like winning the lottery 100 times in a row. This would never happen even if there was an Earth-like planet around every star in the Universe, with the entire population of human-like creatures playing the lottery once every second for the entire age of the Universe (past and present).But there is a very reasonable question about how much we know about the period of time in between when life formed and 600M years ago. Could there have been multiple cycles of complex life that then collapsed back down to single cell life? After all, that's 3B years, 5 times longer than this last period when we went from single celled organisms to us (evolving trees, fish, flowers, multiple epochs of dinosaurs, mammals and yes, humans). From my reading, we have pretty strong evidence against this. The evidence is in chemical traces of life that we use to infer the existence of old life. If there had been vast boom-bust cycles we would see more variety in these chemical markers for life both varying in locations around the globe and also in the depth (which is a proxy for time).When you start thinking about what needs to be done to take a hot rock that's a lot like a global volcano and turn it into the pristine environment that we see, you realize that it takes a lot of time. The atmosphere and oceans were toxic to modern multicellular life and early life had to separate out all the nasty chemicals. This took a lot of time. Even so, it certainly seems like life took its sweet time and then got in a huge hurry over the past 600M years.
How many human years are in 10000 light years?
A light year is a distance of about six trillion miles.Ten thousand times 6E12 equals 6E16. So the distance is 60,000 trillion miles.If a human runs at a speed of six miles per hour, it will take him/her 10,000 trillion hours to complete the journey. This span of time is equal to 1.142 trillion years.Assuming that humans live 80 years, we are talking about a span of time equivalent to 14.27 billion lifetimes.If you add up all the ages in years of all the humans alive today and multiply that number of years by seven, you will get a number close to a trillion years, which is almost enough time to to run the length of 10,000 light years at six miles per hour.
How old would the Earth be in human years?
Well I’m offering a sort of simple answer, I just hope it’s what you’re looking for.So, the main problem here is that we don’t have a sort of “expiration date” for earth. The thing closer to it is when the sun will have become a red giant and will have vaporized earth in 5 billion years from now. The earth is 4.5 billion years already for a grand total of 9.5 billion years, but let’s round it up to a nice 10 billion years.But if the sun kept stable who knows how long the earth could carry along. Perhaps indefinitely.So, let’s say the earth is around 5 billion years old, out of a hypothetical life span of 10 billion years total. If the total hypothetical lifespan of a human was like 100 years (I’m being a bit optimistic here) how much further along would the earth be, in proportion?Well, it’s quite simple: 5:10=x:100 = 5x100/10=x or 50 human years.If you assume the average human to live only 80 years, the earth would be 40 years old in proportion.
How many human years will it take for light to reach the Earth from the farthest observable star?
SDSS J1229+1122 is farthest star.It is 55 Mly (17 Mpc) or 55 million light year. The blue supergiant is illuminating a nebula in the tidal tail of galaxy IC 3418.This record is superseded by a star at redshift z=1.5 (4.4 Gpc) that is being lensed by the galaxy cluster MACS1149.But it is not farthest objectGN-z11 galaxy. With an estimated light-travel distance of about 13.4 billion light-years (and a proper distance of approximately 32 billion light-years (9.8 billion parsecs) from Earth due to the Universe's expansion since the light we now observe,
Are lizard years differnt than human years?
No lizard years are the same as human years so your beardie is 3 years old
How many earth years is in 22 light years?
A light year is a measure of distance, not time, so 22 light years isn't equal to any amount of time. A light year is how far light can travel in one year, and is about 9.5 trillion kilometres, or 6 trillion miles. 22 light years is really far (obviously; about 210 trillion km or 132 trillion miles), but pretty close astronomically speaking.
How far is 600 light-years from Earth?
I had the same question you did. then I really broke it down. The fastest rocket built to date has traveled 25,000 miles per hour, which is roughly almost 7 miles per second. In 1 second, light travels about 186,282.3960 miles. In a minute (60 seconds), that's 11,176,943.76 miles In an hour (60 minutes), that's 670,616,625.6 miles In a day (24 hours) that's 16,094,799,014.4 miles and, in a year (365.25 days) that's 5,878,625,340,009.6 miles So you have to Multiply a light year by 600 so that equals = 3,527,175,204,005,760 many miles. now you need to Multiply 25,000 miles, which is our fastest rocket ship per hour X 24 hours in a day which is 600,000. we can travel in one day. you multiply that by 1 earth year which is 365 days. 219,000,000 miles we can travel in 1 year. So now we will divide The 600 light year distance by the amount of distance we can travel in one year. AND THE ANSWER IS..... IT WILL TAKE 16,105,822.84 ---- a little more then 16 million years traveling at our fastest known rocket ship every built to get to the planet KEPLER - 22B... So unless we start living forever, or create a really fast rocket ship soon we will never see that planet.
Human years verses tiger years?
since tigers have a different sun than humans do, their year is shorter. The circumference of the orbit around their sun is about half of the one of ours, so a tiger year is about a half of a human year.
How many Earth years equals 9 light years?
Light years are light travelling an (earth year ) at 186000 miles per second, we are 93,000,000 miles from the sun , and the light takes approx. 8.5 minutes to reach us, so a quick look at the sun, we see it as it was 8.5 minutes ago.thus 9 light years , means that light has travelled for 9 years , covering approx. 6.5 trillion miles . like the Suns Alpha Centauri being approx. 4 light years away , this SUN is our nearest neighbour , remember a sun is not a planet.so if you see alpha centauri, through a telescope , you are seeing alpha centauri as it was 4 years earlier.