Scientists have found the oldest known piece of our planet.
A blue zircon crystal, found on a sheep ranch in Australia, is about 4.4 billion years old.
The gem is about twice the width of a human hair.
It is the oldest bit of the Earth’s crust ever discovered, according to geoscience professor John Valley, who wrote about the find in the journal Nature Geoscience.
Valley works for the University of Wisconsin-Madison in the U.S.
Valley said the gem helps to confirm the theory that the Earth’s crust formed about 4.4 billion years ago. That’s just 160 million years after the solar system was formed.
Valley studied the gem using a method called “atom-probe tomography.”
That method identified the lead atoms in the crystal.
It confirmed that the zircon was 4.4 billion years old.
The Earth itself is about 4.5 billion years old, when it was a “ball of molten rock,” according to the CBC News website. “Its crust formed relatively soon (after that), 100 million years later.”
The finding suggests that in its early days, the Earth was cool enough to have oceans and perhaps life, earlier than scientists believed.
Scientists are interested in knowing when the Earth first became cool enough to support life, Valley told CBC News.
The dating of the zircon suggests that the planet may have been able to support life (in the form of microbes—single-celled organisms) 4.3 billion years ago.
Valley said there is no evidence that life existed back then, but there is also no evidence that it didn’t.
CURRICULUM CONNECTIONS
By Jonathan Tilly
Writing/Discussion Prompt
Geology (the study of rocks and minerals) is an exciting subject for many reasons. One of the reasons is because by learning about different minerals we learn about our planet and the living things who inhabit it.
Discus with your classmates specific questions that you think geology may be able to answer?
Do an internet search and discover if it already has!
Reading Prompt: Comprehension Strategies
Today’s article explains that the earth’s crust is over 4 billion years old, but this number is hard to imagine. What strategies might you use to help understand just how big 4 billion is?
Junior
Identify a variety of reading comprehension strategies and use them appropriately before, during, and after reading to understand texts (OME, Reading: 1.3).
Intermediate
Identify a variety of reading comprehension strategies and use them appropriately before, during, and after reading to understand increasingly complex texts (OME, Reading: 1.3).
Grammar Feature: Compound Numerals
Numerals are words that are used to describe numbers. Numerals include words such as “two,” “five” and “nine.” Compound numerals use two numerals to describe a number. Compound numerals include words such as “twenty-three,” “fifty-seven,” and “one-hundred.”
Write the correct numeral or compound numeral for the following numbers: 18, 87, 342, 2 000, 467 908.
