Last year, scientist found 50, 1-million-year-old
footprints stuck in the mud! But how do we
know they weren't made yesterday by that neighbor
kid though?
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Howdy folks, Trace here for DNews. The ancient
footprints that British scientists found are
the earliest evidence of human habitation
outside of the African continent. They made
the discovery last year, and according to
a paper just published in PLOS One, "In many
cases the arch and front/back of the foot
can be identified and in one case the impression
of toes can be seen." This is a huge step
in human ancestor research -- 50 footprints,
guys! That's a lot!
When I read this, I thought about the Creation
Museum... see... last Tuesday during the Ken
Ham/Bill Nye Debate on Evolution -- Ham kept
repeating a phrase you hear a lot in evolution-denying
circles, "You can't know because you weren't
there." But we CAN, because OTHER things were
there.
The discovery of carbon dating earned Willard
Libby the 1960 Nobel Prize in Chemistry, because
with this new method, we can estimate the
ages of any organic thing! Yep! ANY! It's
all based on carbon-14, a naturally occurring
radioactive isotope created when cosmic rays
hit the air. It enters the food chain when
plants absorb -- and animals eat it. Then
it lodges itself in their bodies. As the sun
and atmosphere interact constantly, the number
of carbon-14 atoms in your body is the same
as in every other living thing. It's a constant!
Then, every 5,730 years, half of it will decay.
Using this knowledge, we can date bones of
mummies and Pompeiian victims to an estimated
age. Periods of solar and geologic activity,
however, could change how much carbon-14 was
in a specific sample. So, as scientists are
obsessed with corroboration and peer-review,
they found more data to compare to their carbon
dating. Looking at the solar, atmospheric
and geologic data from tree rings, coral beds,
AND ice cores altogether -- we can accurately
date fossils to 60,000 years AND have other
data to back it up... But how do we get something
ONE MILLION years and older??
Well, that's not QUITE as simple, but still
possible. Using the same radiometric dating,
scientists look at the layers of the Earth.
As you go deeper into the crust, the fossils
will have predictable levels of carbon-14
-- but once you get below where science is
confident of the EXACT year -- they look for
other isotopes with longer half-lives. Things
like uranium-238, uranium-235 and potassium-40
ARE all over in the dirt around the fossils.
So when they can't use the carbon-14, they
look at the geologic layer and can determine
when that creature died. Additionally, scientists
have studied the evolution of various plants
and animals so when other plants and tracks
are found in the same area as a fossil they
can date it from that as well. All these different
methods can pinpoint a specific point in time,
and the data has been predictable and consistent.
Thus, there is very little reason for a scientist
to question whether a fossil found at a specific
depth, is a specific AGE.
In this case, these 50 footprints are thought
to be from a pre-human pre-neanderthal relative
called Homo antecessor, or perhaps an Homo
heidelbergensis -- They're close to 800,000
years old and belonged to a group of people
ranging from children to teenagers. They wore
similar shoe sizes to modern humans and stood
as tall as five-foot six (1.67m) They're not
the oldest footprints discovered, not by a
long shot. In Kenya there are 1.5 million-year-old
prints and in Tanzania they've found some
which are 3.5 million years old! It's like
a family foot tree!... Thing. Yeah, let's
not do that.
Are you curious how any other science works?
Send us a tweet @DNews or leave a comment
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