{"id":3973,"date":"2015-07-16T05:26:55","date_gmt":"2015-07-16T05:26:55","guid":{"rendered":"http:\/\/www.lifeandnews.com\/articles\/?p=3973"},"modified":"2016-08-12T05:13:37","modified_gmt":"2016-08-12T05:13:37","slug":"exploring-our-moon-today-to-learn-more-about-earths-youth-billions-of-years-ago","status":"publish","type":"post","link":"https:\/\/www.lifeandnews.com\/articles\/exploring-our-moon-today-to-learn-more-about-earths-youth-billions-of-years-ago\/","title":{"rendered":"Exploring our moon today to learn more about Earth’s youth billions of years ago"},"content":{"rendered":"

Augusto Carballido<\/a>, Baylor University<\/a><\/em><\/p>\n

The surface of the Earth preserves little or no information about its distant past. Constant tectonic activity has recycled Earth\u2019s crust and shifted landmasses. Rainfall, wind, ice and snow have weathered away surface features over billions of years. Most of the craters formed by the impacts of asteroids and comets have been erased from the geologic record, with just over 100 known craters<\/a> remaining on the continents.<\/p>\n

But there is a place that we can go to learn more about the past of our own planet: the moon. In sharp contrast to Earth\u2019s surface, that of the moon is covered with thousands of craters of all sizes, many of them produced shortly<\/em> after the moon was born. The moon doesn\u2019t have the winds, rivers or plate tectonics capable of erasing these marks of ancient impacts.<\/p>\n

For that reason, the surface of the moon is like a window into the early history of our solar system. By studying the chemical composition of rocks and soil on our natural satellite, we could obtain a glimpse of the Earth\u2019s own geological infancy \u2013 including the emergence of life.<\/p>\n

\"\"<\/a>
Artist\u2019s concept of the kind of planetary smash-up that likely created the moon.<\/span>
\nNASA\/JPL-Caltech<\/a>, CC BY<\/a><\/span><\/figcaption><\/figure>\n

Way back when<\/h2>\n

The Earth formed 4.54 billion years ago, after ancient asteroids known as planetesimals piled up into a single, planet-sized body as they orbited the sun. Scientists think the moon formed roughly 70 million years later, when a planet about the size of Mars collided with the young Earth. With the aid of sophisticated computer models<\/a>, experts have shown that this huge collision created a donut-shaped envelope of molten rock and hot gas around the Earth. By calculating how this scorching disk would lose its heat, they\u2019ve deduced that the moon condensed from all this hot material in less than 100 years.<\/p>\n

Fast forward some 500 million years. Around this time, the giant planets Jupiter, Saturn, Uranus and Neptune likely underwent a rearrangement<\/a> of their orbits around the sun, as a result of complex gravitational interactions with myriad planetesimals. This rearrangement sent many asteroids on a collision course with Earth. When they crashed into our planet, their impacts launched terrestrial fragments into Earth\u2019s orbit. A very exciting possibility is that some of those Earth rocks might have landed on the moon.<\/p>\n

If those pieces of Earth did make it to the moon, they\u2019re probably still lying somewhere on the lunar surface. Some studies predict a large concentration of impacts near the moon\u2019s poles<\/a>. In some regions, there may be as much as a golf cart\u2019s mass worth of terrestrial material spread over an area equivalent to 140 soccer fields. Whether this mass is in the form of rocks or tiny dust particles depends on, among other things, how hard Earth\u2019s fragments hit the lunar ground.<\/p>\n

\"\"<\/a>
A 10-km-wide view of the moon\u2019s Lavoisier Crater.<\/span>
\nNASA\/GSFC\/Arizona State University<\/a>, CC BY<\/a><\/span><\/figcaption><\/figure>\n

Messages from Earth on the moon<\/h2>\n

Regardless of their size, terrestrial remnants could contain invaluable information about our planet\u2019s early years. For example, those terrestrial meteorites may hold a record of the chemical composition of the Earth\u2019s ancient mantle, the hot layer of rock between the crust and the core. Learning about the composition of the Earth billions of years ago would allow us to make comparisons with our present-day planet. With more historical data, we could infer how a habitable planet evolves over time, which would enable us to understand extrasolar planetary systems.<\/p>\n

And since we\u2019re talking about habitability, consider this: if there are terrestrial meteorites on the moon, they could potentially give us details about the conditions on Earth right before, or even during, the emergence of life. Stuff to look for on the rock samples blasted off Earth would be organic carbon, minerals gathered by microorganisms, or maybe even fossilized microbes.<\/p>\n

Evidence of Earth\u2019s enigmatic past may also be found on the moon in a more subtle way. Some researchers have suggested that ancient atmospheric gases from Earth could be trapped in the lunar soil<\/a>. Right around the time when the young Earth and moon were heavily bombarded by asteroids, the moon was half as close to the Earth as it is now. It\u2019s therefore possible that Earth\u2019s atmosphere came into contact with the lunar surface.<\/p>\n

To search for traces of earthly gases on the moon, the proponents of this idea suggest using well-known experimental techniques<\/a> to detect the presence of helium, nitrogen and oxygen in lunar grains. The idea would be to measure how much of their various isotopes \u2013 the differing flavors of an element based on how many neutrons they have in the atomic nucleus \u2013 are present. Since the number of neutrons in isotopes changes at known rates, it\u2019s possible to measure how much of one isotope there is in a grain in relation to its \u201cparent\u201d isotope. That would tell you how long those particular elements have been attached to the grains. If it turns out that the isotopes have been there for at least four billion years, there\u2019s a good chance they came from Earth.<\/p>\n

Detecting four-billion-year-old terrestrial oxygen on the moon would be another way to learn about the appearance of life, since atmospheric oxygen would probably have been produced by ancient photosynthetic organisms. Moreover, finding equally old nitrogen could mean that the early Earth did not have a magnetic field as it does today, because electrically charged nitrogen atoms from Earth\u2019s atmosphere would not be capable of reaching the moon had there been a magnetic field.<\/p>\n

\"\"<\/a>
Does the moon hold some of the early Earth\u2019s secrets?<\/span>
\nNASA\/Bill Ingalls<\/a>, CC BY<\/a><\/span><\/figcaption><\/figure>\n

We are still a long way from obtaining a clear understanding of our home planet. But the possibility of lunar exploration by private ventures, in addition to that carried out by national space agencies, raises the prospects of mind-blowing discoveries<\/a> that can shed light on Earth\u2019s mysteries.<\/p>\n

We may well end up repeating the words of Apollo 8 astronaut Bill Anders<\/a>: \u201cWe came all this way to explore the moon, and the most important thing is that we discovered the Earth.\u201d<\/p>\n

\"The<\/p>\n

Augusto Carballido<\/a> is Assistant Research Professor at Baylor University<\/a>.<\/p>\n

This article was originally published on The Conversation<\/a>.
\nRead the original article<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Augusto Carballido, Baylor University The surface of the Earth preserves little or no information about its distant past. Constant tectonic activity has recycled Earth\u2019s crust and shifted landmasses. Rainfall, wind, ice and snow have weathered away surface features over billions of years. Most of the craters formed by the impacts of asteroids and comets have […]<\/p>\n","protected":false},"author":40,"featured_media":5601,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[118],"tags":[],"_links":{"self":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/3973"}],"collection":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/users\/40"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/comments?post=3973"}],"version-history":[{"count":2,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/3973\/revisions"}],"predecessor-version":[{"id":5602,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/3973\/revisions\/5602"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media\/5601"}],"wp:attachment":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media?parent=3973"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/categories?post=3973"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/tags?post=3973"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}