Our Solar System, the Milky Way, was created from a dense could of interstellar dust and gas that collapsed and turned into a swirling, spinning nebula.
This nebular is made up of hydrogen and helium, and a little amount of other elements, which combined together and reacted in order to create other materials which in turn created the planets of our solar system we know today.
Only rocky materials could survive the heat of the sun, which is why the closet planets, Terrestrials, to the sun in our solar system are made up of rocks and metals. On the other hand, the outer planets of our solar system, the Jovian planets, are made up of ice, liquid, and/or gas because gravity was able to pull these materials together.
Fun fact! The reason our Milky Way has its names is because it appears as a “milky band of light” in the night sky.
Opportunity and Spirit are two rovers that have been to the incredible Red Planet – Mars.
Opportunity launched out of Florida in 2003 and landed on Mars in 2004, which was soon after its twin Spirit landed. Opportunity is one of the more well known rovers, in that it broke a record of operating for about 15 years, while making key discoveries in our astronomical history. Some of these discoveries including finding evidence that Mars was once able to sustain life. Opportunity also drove the steepest slope by any rover on Mars.
There were many different parts of opportunity such as a pan-cam (panoramic camera), nav-cam (navigation camera), a Mini-TES (miniature thermal emission spectrometer), and other scientific instruments that were key aids in opportunity’s discoveries. Unfortunately, due to a strong dust storm on Mars in 2018, Opportunity was cut from Earth.
Spirit also launched out of Florida in 2003, and landed on Mars in 2004, a little before its twin rover Opportunity, described above. Spirit contained, if not all the same then similar, scientific instruments. Spirit operated for 6 years, and some of its discoveries include discovering that there was once water on mars. Its goal was to study the history/climate of sites on Mars that might have previously had life. Spirit ended its mission in March of 2010.
You can find pictures and more about The Adventure Twins here.
Meteors are common celestial bodies. There are a lot of fine dust and some fine solid matter in the solar system, which we call meteoroids. Despite their relatively small size, they also orbit the Sun. If they break into the atmosphere and have violent friction and collisions with the atmosphere, they will burn and emit dazzling light. These meteoroids burn up as they fly high and are what we see as meteors. Meteors generally appear at an altitude of about 80-120 kilometers from the ground. Usually, meteoroids are evenly distributed around the Earth. If the Earth didn’t rotate and revolve, then there should be an equal number of meteors coming in from all directions. As the Earth orbits the sun, the number of meteors seen at different times varies.
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So far, there are several hypotheses about the formation of the earth and the solar system. There are two main popular hypotheses: one believes that the solar system was produced by a violent accidental mutation, the catastrophe theory; the other believes that the solar system evolved gradually in an orderly manner, that is, evolutionary theory.
In 1755, the German philosopher Kant proposed the hypothesis of the formation of the solar system based on Newton’s principle of universal gravitation. He believed that the sun, planets, and moons in the solar system formed gradually from nebulae—thin clouds of granular matter. In 1796, French astronomer Laplace also proposed a nebula theory similar to Kant’s. Later generations often combine the two together, collectively referred to as “Kant-Laplace nebula theory”. This assumption dominated most of the 19th century.
Scientists believe that stars form as spherical fragments of a primordial nebula that runs through the Milky Way. Under the action of its own gravity, it constantly shrinks and creates a vortex. The vortex shattered the nebula into a multitude of fragments, each of which gradually transformed into a star. The sun is one of them, and it is also constantly shrinking and rotating, forming the original sun in long-term motion. The surrounding objects continue to gather, collide, and become larger and larger, forming today’s eight planets. The material around the planets also gradually formed moons in this way. This is one of the leading hypotheses for the formation of the solar system.
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With countless spacecraft having been launched throughout a long history of space exploration, what is next for NASA?
Pictured above is a computer-rendered image of NASA’s Orion Spacecraft
Looking to shoot beyond the Moon and delve into the nearly untapped knowledge of Mars, the Orion project is what’s next on NASA’s agenda, as they prepare to send a series of Orion shuttles into space to build up to a manned mission to Mars.
The Orion mission has the ultimate goal of exploring Mars like never before, using the science and technology of satellites and spacecraft past while also containing some of the newest technology available.
The Orion craft is first set to launch under the title Artemis I and spend about six weeks shooting thousands of miles past the Moon. The Artemis I mission is in place to test the spacecraft, its technology, its aborting capabilities, and its capability of returning home safely. This check, while also collecting data from space, will ensure that the next mission Artemis II, is safe for humans to ride on and venture farther into space than any human has gone before.
In Andy Weir’s The Martian, NASA plans to send a supply probe to Mars to save the stranded astronaut Mark Watney through what’s called the ‘Hohmann Transfer Orbit‘. What exactly is the Hohmann transfer orbit? And when the carrying capacity of rockets is limited, why does a probe following this orbit saves limited and precious fuel?
This maneuver is proposed by German scientist Walter Hohmann in his 1925 book The Attainability of Celestial Bodies. This orbital maneuver requires two thrusts to bring a probe from a lower orbit to a higher orbit (see Figure 1 below). The initial thrust is Δv, which is preferably applied when the probe is at its periapsis (lowest point of its orbit). This initial thrust raises the apoapsis (highest point) of its orbit, and sends the probe to an elliptical transfer orbit. The second thrust Δv’ raises the periapsis of its orbit, allowing the probe to match and enter the desired, higher orbit.
If we wish to let the probe intercept an object at the higher orbit (in our case Earth and Mars), we have to take the relative positions of Earth and Mars, and the typical travel time of the transfer into account. For Earth and Mars, the window for the Hohmann transfer opens once every 26 months, and a spacecraft following this orbit takes 9 months to reach Mars.
Hohmann transfer orbits are typically applied when the amount of fuel a spacecraft can take is limited. If time is of the essence, a probe can reach Mars much faster if it is capable of producing more thrust. In reality, the Hohmann transfer orbit requires less thrust when considering the gravitational effects of the planets at the initial and final positions, as maneuvering through the gravitational well of a planet conserves momentum and saves fuel. Also, the Hohmann transfer orbit can be applied backwards, sending a spacecraft to a lower orbit around a common central object by reversing the direction of the thrust.
I am excited to see how space agencies will apply this maneuver when we decide to send people to Mars! Here are some links to the Hohmann transfer orbit and the Oberth effect (powered flyby).
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I’ve always wondered how rare it is for Earth to exist and support life on it, and now I know that out of the billions of solar systems, Earth is the only planet we know of to support life on it currently. Earth had to be at just the right distance from the Sun for water vapor to condense and fall to the surface as rain. Earth had to be just big enough for volcanism and outgassing to produce an atmosphere and for its gravity to keep atmospheric gasses from escaping. Earth had to rotate just fast enough for wind and other weather to exist. Even with all that, we would still not be able to exist on Earth if it wasn’t for the fact that Earth is the only planet out of all terrestrial worlds to be shaped primarily by ongoing plate tectonics, which means we have a stable climate to live in. All in all, I would consider ourselves very lucky to be alive.
On the morning of February 15, 2013, an undetected meteor the size of a six-story building exploded over the city of Chelyabinsk, Russia. At 20 meters long, it reached speeds of 60,000 km/h before detonating with the force of a 500-kiloton nuclear bomb. Witnesses saw a flash brighter than the Sun before hearing a delayed seismic blast that tore down walls, shattered glass up to a hundred miles away, and injured over a thousand. Eye damage and burns from the intense ultraviolet radiation was also reported.
To put the blast into perspective, Fat Man, the nuclear bomb dropped over Nagasaki, had a blast yield of 21 kilotons. Were the meteor to make contact with the surface, the resulting damage would have been catastrophic.
This begs the question: Why wasn’t this meteoroid detected? According to NASA, the meteoroid was relatively small, and its path of impact came towards Earth out of the Sun. Asteroid telescopes have a brightness magnitude limit of +24, a scale such that higher magnitudes represent dimmer objects. The Sun has a magnitude of -27, for example. Together, these factors suggest that the meteoroid would not have been visible until only two hours before impact.
Nuclear fusion is the process of combining, or fusing, two or more small nuclei into a larger one, creating energy as a byproduct. Stars like the Sun constantly emit energy through nuclear fusion because their cores are filled with high-speed, hot plasma. More specifically, the Sun’s extremely hot core of 15 million K allows for nearly 1038 fusion reactions to take place in the form of proton-proton chains where 4 hydrogen protons are converted into 1 helium, 2 protons, 2 positrons, and gamma rays. This reaction is only possible because the hot, high-speed plasma in the Sun’s core forces protons to fuse together to form a proton-neutron pair, employing the Strong Force and overwhelming the electromagnetic forces that separate positively charged particles. Nuclear fusion is different from nuclear fission, the process used by nuclear reactors to generate energy, because fission separates larger nuclei into smaller nuclei.
Currently the largest known volcano in the Solar System, Olympus Mons stands at a remarkable 25 km high, which is almost 3 times the height of Mount Everest, and is wide as Arizona. Compared to the largest active volcano on Earth, Mauna Loa, Olympus Mons is 100 times larger in volume, a seemingly odd feat considering Mars is just over half the size of Earth.
Olympus Mons is a shield volcano. It was formed by “runny” lava that spread a far distance before solidifying, which caused very shallow slopes. This lava is a consequence of volcanism, the process in which underground molten rocks are pushed to the surface by surrounding higher density rock and internally trapped gasses. Similar to other volcanoes in the Tharsis region, Olympus Mons was able to amass a great size compared to volcanoes on Earth due to lower gravity and higher eruption rates. Mars also has limited plate movement when compared to Earth, meaning erupted lava tends to stay in a single spot.
The surface of Olympus Mons is relatively smooth compared to the rest of Mars. We can conjecture that the volcano must be somewhat young then, which supports the possibility that it may erupt again in the future. It also isn’t unique; there are three other similar sized behemoths neighboring Olympus Mons, collectively known as Tharsis Montes.
