Earth is the Most Exotic Place In The Universe

I’m often asked by students in my community education astronomy classes whether any new elements have been found in outer space unknown on Earth. The answer to the question is no – nature uses the same 98 natural elements to fashion everything from the familiar stars and planets to those in the farthest galaxies we can see. Outside of an occasional compound or mineral, Earth is the place where you’ll find more exotic elements than anywhere else in the universe.

An element is a pure substance made of just one type of atom. What sets one element apart from another is the number of protons in the nuclei of its atoms. Any atom with six protons will always be carbon, 79 protons gold, 94 protons plutonium and 1 proton hydrogen. The proton number is also the element’s atomic number on the periodic table of elements. Elements in the table are arranged according to their atomic number.

Atoms are made of protons, neutrons and orbiting electrons. The number of protons in atom's nucleus makes it unique from all the others. Hydrogen, the simplest element, has one while carbon has six.
Atoms are made of protons, neutrons and orbiting electrons. The number of protons in atom’s nucleus makes it unique from all the others. Hydrogen, the simplest element, has one; carbon has six.

The two most common elements are hydrogen and helium, numbers 1 and 2 in the periodic table; together they make up 98% of all the visible matter in the universe. The remaining 2% includes everything else from lightweight lithium (number 3) all the way up to californium (98), the heaviest natural element found on Earth and in the stars. Californium is unstable and “decays” into simpler elements. Although scientists make it in the lab by bombarding berkelium (97) with neutrons, trace amounts of this very rare element are found naturally in rich uranium deposits.

When I was in high school studying chemistry, the periodic table of elements ended at Lawrencium (103). At present there are 118 elements, the most recent one created in the lab being ununoctium (you-nah-NOC-tee-um). Matter of fact, all the elements beyond 98 are artificial, brought to life in nuclear reactors or in particle accelerator experiments. They live very short lives. With so many positively-charged protons pushing against one another in their nuclei, these elements quickly break apart into simpler ones in a process called radioactive decay.

Artist's concept of the first stars in the Universe turning on some 200 million years after the Big Bang. These first suns were made of almost pure hydrogen and helium. They and later generations of stars cooked up the heavier elements from these simple ones. Credit: NASA/WMAP Science Team
Artist’s concept of the first stars in the Universe turning on some 200 million years after the Big Bang. These first suns were made of almost pure hydrogen and helium. They and later generations cooked up heavier elements that were later incorporated into the sun and us. Credit: NASA/WMAP Science Team

Back at the time of the Big Bang, when the universe sprang into existence, only the simplest elements – hydrogen, helium and trace amounts of lithium – were cooked up. You can’t build a planet from such fluffy stuff. It took the first generation of stars, which formed from these basic building blocks, to synthesize more complicated elements like carbon, oxygen, sulfur and the like via nuclear fusion in their cores.

When the stars exploded as supernovae, not only were these brand new elements blasted into space, but the enormous heat and pressure during the blast built even heavier elements like gold, copper, mercury and lead. All became incorporated in a second generation of stars. And a third.

The 2% of star-made elements, which include carbon, oxygen, nitrogen and silicon among others, went to build the planets and later became essential for life. We’re made of highly processed material you and I. The atoms of our beings have been in and out of the cores of several generations of stars. Think about this good and hard and you might just get in touch with your own “inner star”.

Common table salt is formed of tight-fitting atoms of sodium and chlorine. Each elements has its own individual character - one's a flammable metal (sodium), the other a dangerous gas. Put them together and you create a safe, tasty edible. Credit: Wikipedia
Common table salt is formed of tight-fitting atoms of sodium and chlorine. Each elements has its own individual character – one’s a flammable metal (sodium), the other a dangerous gas. Put them together and out comes a safe, tasty seasoning. Credit: Wikipedia

Let’s reframe the question about exotic materials in space not present on Earth. Instead of elements, if we look at compounds, we hit paydirt. A compound is also a pure substance but consists of two or more chemical elements joined together. Familiar compounds include water (two hydrogens joined to one oxygen) and salt (one sodium and one chlorine).

A selection of molecules (chemical compounds) including water found in the Orion Nebula detected by the Herschel Space Telescope. Credit: ESA, HEXOS and the HIFI Consortium E. Bergin
A selection of molecules (chemical compounds) including water found in the Orion Nebula detected by the Herschel Space Telescope. Credit: ESA, HEXOS and the HIFI Consortium E. Bergin

Astronomers have found about 220 compounds or molecules in outer space many of them with siblings on Earth but some alien. We don’t have to look far to find them since a few have been delivered right to our doorstep as rocky packages called meteorites.  Here’s a short list of new minerals that formed within asteroids (where meteorites originate) under conditions very different from those found on Earth:

Barringerite – a metallic compound made of iron, nickel and phosphorus
Oldhamite – brown mineral made of calcium, magnesium and sulfur
Kosmochlor  – green mineral containing calcium, chromium, silicon and oxygen

How about new stuff on planets and comets? Astronomers have discovered compounds in the atmospheres of the giant planets Jupiter, Saturn, Uranus and Neptune like silane (silicon-hydrogen), arsine (arsenic-hydrogen) and phosphine (phosphorus-hydrogen) that don’t exist naturally on Earth. Humans have created all three in the lab and put them to good use in various industries including the manufacture of semi-conductors.

Helium was first discovered in the spectrum of the sun by French astronomer Pierre Janssen in 1868 by observing sunlight through a prism during an eclipse. It was discovered on Earth in 1895. Credit: Bob King
Helium, the gas that floats our balloons, was first discovered in the spectrum of the sun by French astronomer Pierre Janssen in during a solar eclipse in 1868. Scientists finally found it on Earth in 1895. Click to learn the helium story. Credit: Bob King

And then there’s Brownleeite, a manganese silicide found in 2003 in a dust particle shed by comet 26P/Grigg-Skjellerup. Moving beyond the solar system, astronomers see unusual long-chained carbon molecules in space that couldn’t form on Earth because oxygen would tear them apart. Space is their safe haven.

So, Earth is the location in the Universe where you’ll find more exotic elements than anywhere else. Thanks to human activity and the complicated molecules that wound together to form life, Earth’s the most exotic place in the universe.

What is Plutonium?

Periodic Table of Elements

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The name itself conjures up imagines of mini nukes and sophisticated space-age gadgets doesn’t it? Well for some people it does. For others, Plutonium (Pu, atomic number of 94 on the periodic table of elements) spawns images of nuclear reactors, atomic energy and nuclear waste. All of these are true to an extent, but the reality behind this radioactive element is understandably more complex. For starters, plutonium is a silvery white actinide metal that is radioactive, and hence quite dangerous when exposed to living tissue. It is one of the key ingredients in the making of atomic weapons, but is also produced in nuclear reactors as a result of slow fission. There are also several isotopes of the element, but for our purposes, the most important is Plutonium-239, a fissile isotope that is used for both nuclear power and weapons and has a half-life of 24,100 years.

Plutonium-238 was first discovered as an element on Dec.14th1940, and then chemically identified on February 23rd 1941through the deuteron bombardment of Uranium in a cyclotron by Glenn T. Seaborg and his team of scientists, working out of the University of California in Berkley. The team submitted a paper publishing their findings; however, this paper was retracted when it became clear that Plutonium-239 was a fissile material that could be useful in the construction of an atomic weapon. At this time, the US was deep into the development of an atomic bomb (aka. the Manhattan Project) because it was believed that Germany was doing the same. For this reason, publication of Seaborg’s work was delayed until 1946, a year after the Second World War ended and security surrounding atomic research was no longer a concern. Seaborg decided to name the element after Pluto because of the recent discovery of element 93, Neptunium, and felt that element 94 should accordingly be named after the next planet in the Solar System.

Towards the end of WWII, two nuclear reactors were created which would produce the plutonium used in the construction of “Trinity”, “Fat Man” and other atomic weapons. These were the X-10 Graphite Reactor facility in Oak Ridge (which later became the Oak Ridge National Laboratory) and the Hanford B reactor (built in 1943 and 45 respectively). Large stockpiles were subsequently built up by the US and USSR during the Cold War, and have since become the focus of nuclear proliferation treaty concerns. Today, it is estimated that several tonnes of plutonium isotopes exist in our biosphere, the result of atomic testing during the 1950’s and 60’s.

We have written many articles about Plutonium for Universe Today. Here’s an article about Plutonium shortage in NASA, and here’s an article about Plutonium – 238.

If you’d like more info on Plutonium, check out Wikipedia – Plutonium, and here’s a link to World Nuclear page about Plutonium.

We’ve also recorded an entire episode of Astronomy Cast all about Nuclear Forces. Listen here, Episode 105: The Strong and Weak Nuclear Forces.

Sources:
http://en.wikipedia.org/wiki/Plutonium
http://www.world-nuclear.org/info/inf15.html
http://periodic.lanl.gov/elements/94.html
http://en.wikipedia.org/wiki/Nuclear_proliferation
http://en.wikipedia.org/wiki/Actinide
http://en.wikipedia.org/wiki/Cyclotron

Where is Uranium Located

Periodic Table of Elements

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Uranium is a silvery white metal and is number 92 on the table of periodic elements. It is a well-known element because of its radioactive properties which are used in nuclear reactor powered by nuclear fission. We know that this element is very sought after as source of power by many countries wanting to shift from oil and fossil fuel based economies. So where is Uranium located and how do miners harvest it?

To understand how it is found we need to learn about how it was discovered. Uranium was first discovered by German chemist martin Heinrich Klaproth in 1749 when he was heat treating Minerals. He named the new mineral produced Uranium. The first pure sample of Uranium metal was produced in 1841 by Eugène-Melchior Péligot an analytical chemist who was heat treating Uranium tetrachloride. Demand for Uranium outside its more mundane uses as a window dye was initiated by the discovery of its fissile nuclear properties by Enrico Fermi. Mr. Fermi would go on to lead the Manhattan Project in 1942 that lead to the creation of nuclear weapons and reactors. When the energy it produced was realized the demand for Uranium immediately increased.

So where is Uranium located? In space Uranium is formed naturally occurring in supernovas. However since we can’t even travel to the nearest star it is just a minor fact. On Earth Uranium is surprisingly plentiful for a heavy metal. In fact estimate place the Earth’s supply of Uranium at 30 times that of Silver. This is because Uranium can be found in topsoil anywhere on the planet as well as in the mantle. Scientist even theorize that the natural decay of Uranium and other radioactive elements is what heats the Earth’s core and mantle causing convection currents in the magma and creating plate tectonics.

Uranium can be found as part of a lot of different minerals such as uranite. The element rarely occurs in its pure form. Even then the more fissile kinds of isotopes aren’t plentiful in nature. Uranium ore is the main source of uranium even though with the discovery of how wide spread it is in the Earth’s crust and scientist are looking for inexpensive ways to process it from the soil. In the meanwhile Uranium ore can be found in mines in Canada, Russia, and in Sub-Saharan Africa.

We have written many articles about Uranium for Universe Today. Here’s an article about the lunar Uranium, and here’s an article about nuclear fission.

If you’d like more info on Uranium, check out Wikipedia, and here’s a link to the Encyclopedia of Earth.

We’ve also recorded an entire episode of Astronomy Cast all about the Atom. Listen here, Episode 164: Inside the Atom.

Sources:
Wikipedia
Encyclopedia of Earth
World Nuclear Association

Where is Helium Found

Universe

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Helium is the second lightest element in the known universe. It is also the second most abundant. According to some estimates helium accounts for as much as 24 percent of the Universe’s mass. This element is also plentiful since it is a prime product of fusion nuclear reactions involving hydrogen. So if it is so plentiful where is Helium found?

The problem is that just because an element is common in the universe at large does not mean that it is common on Earth. Helium is an element that fits this scenario. Helium only accounts for 0.00052% of the Earth’s atmosphere and the majority of the helium harvested comes from beneath the ground being extracted from minerals or tapped gas deposits. This makes it one of the rarest elements of any form on the planet.

Like mentioned before Helium is rare on Earth but there are places where it is readily found. If you look at space the majority of helium is in stars and the interstellar medium. This is due to the fusion reaction that powers most stars fusing single hydrogen atoms to create helium atoms. This process balanced with a star’s gravity is what helps it to stay stable for billions of years. On Earth the majority of helium found comes from radioactive decay. This is the opposite nuclear reaction called fission that splits atoms. For this reason radioactive minerals in the lithosphere like uranium are prime sources for helium.

On Earth there are key locations where concentrated helium can be harvested. The United States produces the majority of the world’s helium supply at 78%. The rest of the world’s helium is harvested in North Africa, The Middle East, and Russia. The interesting thing is that thanks to these deposits the world’s demand for helium is being met regularly. Also unlike petroleum which can decades to form from organic material, 3000 metric tons of Hydrogen is produced yearly. Until helium demand reaches at least the same level of demand as petroleum there it little chance of that demand outpacing supply.

Helium is looking to be a major player in the near future. Governments are looking into using the gas as source of hydrogen for fuel cells and other transportation technologies. At the moment the promise is still tentative but at least with better surveying and knowledge of gas deposits there will be a supply waiting if becomes the next major element to power human civilization. In the meanwhile ours is still a planet beholden to carbon.

We have written many articles about Helium for Universe Today. Here’s an article about the discovery of Helium, and here’s an article about composition of the Sun.

If you’d like more info about helium on Earth, check out NASA’s Solar System Exploration Guide on Earth. And here’s a link to NASA’s Earth Observatory.

We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.

Source: Wikipedia