InSight is short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, and is NASA’s next big spacecraft. A little contrived, but its memorable. InSight is a Mars lander designed to study the inside of Mars: the crust, mantle, and core. It does so by measuring the planet’s seismology, heat flow, and precision tracking. By studying these variables, the mission will seek to uncover how a rocky body forms and evolves to become a planet. Its secondary mission will be to determine the level of tectonic activity on Mars. Mars has low levels of geological activity, which means that it well preserves the record of its formation and can provide valuable insight (get it) into how the terrestrial planets formed.
The lander was primarily built by Lockheed Martin, who built NASA’s first Mars lander in 1976. Lockheed Martin built most of the lander in Colorado, and completed most of the manufacturing three years ago. NASA originally hoped to launch in May 2016, but ran into technical difficulties with one of the instruments. The mission was pushed to 2018, the next time when Earth and Mars’ orbits are lined up.
The launch period is set for May 5, 2018. InSight will launch from a United Launch Alliance Atlas V rocket, and is scheduled to arrive on Mars November 26, 2018.
It is very hard to drill to the deepest part of the Earth. However, there are some indirect measurements that allow us to know limited information about the interior structure of the Earth. One of those is the measurement of seismic waves.
By knowing the characteristic of seismic waves, we are able to identify the properties of the material that the waves pass through since different types of material affect the speed of the waves by different amount. Then, the precise measurement is based on the duration that certain seismic waves travel after an earthquake, indicating the specific properties of the materials that the waves encountered.
There are two types of seismic waves: P-waves and S-waves. P-waves are able to pass through solid and liquid materials, whereas S-waves are only able to pass through solid material. With the above information, the structure of the interior of the Earth can be calculated, which has a liquid outer core and a solid inner core.
Nuclear Fusion refers to the nuclear reaction in which atomic nuclei of low atomic number elements fuse to form a heavier nucleus. This reactions releases energy and is how the sun and other stars generate light and heat. Energy is produced during the smashing of the lighter atoms, which is most easily achieved on Earth by combining two isotopes of hydrogen: deuterium and tritium. Nuclear fusion yields energy because the mass of the combination will be less than the sum of the masses of the individual nuclei,. If the combined nuclear mass is less than that of iron at the peak of the binding energy curve, the nuclear particles will be more tightly bound than they were in the light nuclei, and that decrease in mass is compensated in the form of energy according to the Einstein relationship.
Nuclear Fusion refers to the nuclear reaction in which atomic nuclei of low atomic number elements fuse to form a heavier nucleus. This reactions releases energy and is how the sun and other stars generate light and heat. Energy is produced during the smashing of the lighter atoms, which is most easily achieved on Earth by combining two isotopes of hydrogen: deuterium and tritium. Nuclear fusion yields energy because the mass of the combination will be less than the sum of the masses of the individual nuclei,. If the combined nuclear mass is less than that of iron at the peak of the binding energy curve, the nuclear particles will be more tightly bound than they were in the light nuclei, and that decrease in mass is compensated in the form of energy according to the Einstein relationship.
Every year, approximately 20% of the energy generated by the United States comes from nuclear power. Throughout the years, our consumption of nuclear power has brought with it over 90,000 metric tons of nuclear waste. 97% of nuclear waste in the world has been classified as low- or intermediate- level waste (LLW or ILW) while the remaining 3% has been classified as high-level waste (HLW). The difference in the levels refers to the radioactive content and half-life (i.e., the time needed for a source to lose half of its radioactivity) of the waste.
Low-level waste(LLW) contains the minimal amount of radioactivity. It often refers to the type of waste that is generated from daily operations in hospitals, laboratories, and various industries. It can range from contaminated gloves used in university projects to parts of a nuclear power plant. LLW is generally disposed of either by waiting for its radioactivity to drop low enough to dispose of as normal waste or amassed and stored in government-approved containers close to the Earth’s surface.
Intermediate-level waste(ILW) has higher radioactive levels and requires shielding when handled. It often refers to the less radioactive byproducts of nuclear energy operations and can also include parts of a nuclear power plant. ILW disposal normally requires the waste to be reprocessed and incorporated into non-radioactive objects like cement or bitumen before being stored in a container. It is also stored close to the Earth’s surface.
High-level waste (HLW) contains the most radioactivity. It often refers to the most radioactive byproducts of nuclear energy operations. HLW is generally stored at nuclear reactor sites until it can be safely transferred to government-approved containers composed of concrete, steel, and heavy elements in the periodic table such as lead.
Currently, there is no permanent disposal solution for nuclear waste. The only way radioactive materials can become harmless to humans is through decay. For high-level waste, this can mean hundreds of thousands of years.
There is much concern today over the safety and conceivability of generating more nuclear waste. One of the most important considerations is the location of permanent disposal sites. Radioactive leakage can have devastating results, as we have seen from Russia’s Chernobyl and Japan’s Fukushima nuclear accidents.
Although places such as the Yucca mountain site in Nevada have lobbied hard for a license for permanent nuclear disposal, there is still, as of to date, no permanent nuclear disposal site in the United States. Part of this is due to public perception of nuclear activity. Nuclear testing sites during World War II in New Mexico have still had a lingering effect on the residents of the surrounding areas even after 70 years. Despite the potential economical stimulation of nuclear power production, many regions of the United States are fearful of similar results.
Today, global nuclear waste is projected increase to about 140,000 metric tons over the next several decades. While there is still ambiguity surrounding the problem of disposal, many organizations are working to find a safe and permanent solution. A brief strategic plan by the Department of Energy for nuclear waste disposal within the United States can be found here.
It is important to understand that Climate Change is something that normally happens to planets. Earth will be around for a while. It does not matter if it goes through climate change; the Earth will remain. It is the humans and animals who will die off if the planet warms immensely. That is why we have to remember that our efforts to sustain the planet are not “for the Earth,” but for us and the animals that live here. That should be motivation enough to keep our planets climate from heating to a point that humans would not be able survive.
When you think about humans moving to other planets, your train of thought probably leads you to think about Mars. Sending spacecrafts to Mars, talks of terraforming Mars, the works.
But another planet that has been a subject of many science fiction stories is none other than Earth’s sister planet: Venus.
Venus’ surface is hostile. So far, we’ve sent more than 20 successful space missions to observe the planet. But because the atmospheric pressure at the surface is over 90 times that of Earth’s, only a few spacecrafts managed to reach the surface. Even then, they survived only an hour before collapsing.
Not only that, the temperature at the equator reaches as high as 500° Celsius – higher than the melting point of lead. This is one of the significant reasons why water is not just scarce, but completely absent in any form.
Despite all of this, there are ideas of colonizing Venus’ atmosphere. One of the main proposals is using a breathable air (a nitrogen / oxygen solution) as a lifting gas. Nitrogen and Oxygen have less density than the lower atmosphere of dense carbon dioxide and sulfuric acid, but not so light such that it escapes Venus’ atmosphere entirely. Calculations show that the breathable, air-filled balloons would hover around a height of 50 kilometers, where the temperature averages around 75° C / 167° F. If there was a way to further decrease density so the balloons hover a mere 5 km higher, the temperatures would further decrease to 27° C / 81° F.
When you think about humans moving to other planets, your train of thought probably leads you to think about Mars. Sending spacecrafts to Mars, talks of terraforming Mars, the works.
But another planet that has been a subject of many science fiction stories is none other than Earth’s sister planet: Venus.
Venus’ surface is hostile. So far, we’ve sent more than 20 successful space missions to observe the planet. But because the atmospheric pressure at the surface is over 90 times that of Earth’s, only a few spacecrafts managed to reach the surface. Even then, they survived only an hour before collapsing.
Not only that, the temperature at the equator reaches as high as 500° Celsius – higher than the melting point of lead. This is one of the significant reasons why water is not just scarce, but completely absent in any form.
Despite all of this, there are ideas of colonizing Venus’ atmosphere. One of the main proposals is using a breathable air (a nitrogen / oxygen solution) as a lifting gas. Nitrogen and Oxygen have less density than the lower atmosphere of dense carbon dioxide and sulfuric acid, but not so light such that it escapes Venus’ atmosphere entirely. Calculations show that the breathable, air-filled balloons would hover around a height of 50 kilometers, where the temperature averages around 75° C / 167° F. If there was a way to further decrease density so the balloons hover a mere 5 km higher, the temperatures would further decrease to 27° C / 81° F.
It is currently known that Mars has only a fraction of the atmosphere that Earth has. This could be due to a number reasons ranging from its further distance away from the Earth and its smaller size in comparison to Earth and Venus, however, all terrestrial worlds had something that could have resembled an atmosphere at some point. Mercury and the Moon lost theirs early on because they were just too small to stay geologically active and have enough gravity to keep an atmosphere around it. Mars on the other hand shows extensive evidence of having had a thick enough atmosphere with a sufficient greenhouse effect to have liquid water on its surface. But currently, there are only polar ice caps and an atmosphere so thin it hardly makes a difference.
NASA’s representation of the ocean that was believed to have existed.
Without an atmosphere and without the presence of water, where did it all go? Currently, NASA is using their new Webb telescope to determine where it all went. Their current theory is that much of the water was broken apart by UV rays entering the atmosphere. This resulted in many of the Hydrogen atoms gaining enough energy to escape the atmosphere because Hydrogen is the lightest subatomic particle. Without Hydrogen, water cannot reform again because the Hydrogen is forever in space. NASA intends to use their new Webb telescope to test this theory because the telescope can measure the presence of deuterium, a heavier isotope of Hydrogen. Because it is harder for a heavier possible to obtain enough energy to escape, there should be a higher presence of deuterium on Mars.
Harnessing nuclear energy as an energy source has long been an idea surrounded in mystery and fear. Very few people actually know how nuclear power plants work, but many people know how catastrophic nuclear reactor meltdowns can be. However, the kind of nuclear energy we can currently control in nuclear power plants is only one of two kinds of nuclear energy. Current reactors rely on nuclear fission-the breaking of large atoms into smaller atoms. Nuclear fusion, combining small atoms into bigger atoms, is currently demonstrated in the core of our sun and hydrogen bombs. That raises the question: how close are we to being able to (safely) utilize nuclear fusion?
Nuclear fusion has long been seen as a better alternative to nuclear fission for 3 main reasons: the elements needed for fusion are much more common than the ones needed for fission, the by-products of fusion are much safer than fission’s by-products, and fusion could potentially lower the risk of reactor meltdowns. The biggest problem scientists currently struggle with is figuring out the “breakeven energy point” of nuclear fusion: the point where we maximize our energy output without fearing a runaway reaction resulting in a nuclear explosion. Currently there are two approaches that are making serious headway towards reaching this breakeven point. Internal Confinement uses lasers to compress a chunk of Hydrogen and force it to undergo nuclear fusion. The only problem is that those lasers currently use more energy than the nuclear fusion creates, but a recently invented laser promises to output much more energy which could trigger stronger nuclear fusion reactions. The other leading idea is Magnetic Confinement Fusion that uses magnetic fields to compress the hydrogen into nuclear fusion. Recently, a very small research team in California created a new way to increase the density, temperature, and confinement time of the hydrogen in a MCF system, which could lead to higher energy outputs. Both of these systems have seen recent breakthroughs, but they might still be quite a way away from reaching the break-even energy point. With that said, mankind is closer to safely harnessing nuclear fusion than ever before.
Diagram illustrating the Internal Confinement principle Source
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