My Science School

Have you ever wondered where precious metals like gold come from? Or how they became embedded in the deep crevices of our planet?

A gift from the stars

Gold is extraterrestrial. This means instead of arising from our planet's rocky terrain, this metal was actually created in space. Its presence on the Earth is a consequence of the cataclysmic explosions called supernovae. This powerful and luminous explosion occurs towards the end of a star's life.

Supernova

Matter is made up of atoms. These atoms consist of subatomic particles like protons (positively charged particles), electrons (which have a negative charge) and neutrons (neutral particles that form the centre of an atom). The region of an atom that accommodates neutrons is called a nucleus.

When two or more atoms' nuclei (plural of nucleus) merge to form a heavier atom, a large amount of energy is dissipated into the surrounding. This process is known as nuclear fusion.

Stars are mostly made up of hydrogen, which is the simplest and the lightest of all the elements. With time, the enormous gravitational pressure of so much material compresses and triggers nuclear fusion in a star's core.

The energy released due to this fusion is the reason why stars shine. Over millions of years, this fusion transforms hydrogen into heavier elements like helium, carbon, and oxygen. These heavier elements burn faster and faster to make iron and nickel.

Towards the last phase of a stars life, this fusion is unable to release enough energy, and the pressure from the core forces the outer layers of the heavenly body to collapse into the centre. This sudden injection of energy results in the explosion of the star or a supernova.

The pressure of this explosion is so high that it forces various subatomic particles to fuse and form neutrons. These neutrons are then captured and combined by the residual heavy metals from the star. This leads to the formation of heavier elements like gold, silver, lead and even uranium. The formation of heavy metals in a supernova takes place within seconds.

The remnants of supernova

The expanding shock wave from the explosion propels the remnants through space. The supernova debris enriches the space clouds and condenses to form new planets and stars.

Researchers have found that Earth's reserve of gold is most likely a direct consequence of this phenomenon. This would mean that the cosmic cloud that condensed to form our planet had gold particles, which were then kneaded into the planet's crust due to the movement of the tectonic plates and other Geo-thermal activities.

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On May 15, 1963, the last mission of Project Mercury got under way. Astronaut Gordon Cooper closed out things in style as his flight stretched the capabilities of the Mercury spacecraft to its limits.

The Mercury Seven, also referred to as the Original Seven, were a group of seven astronauts selected to fly spacecraft for Project Mercury - the first human space flight program by the U.S. Even though there were some hiccups, the project, initiated in 1958, was largely successful in its three goals of operating a human spacecraft. investigating an astronaut's ability to work in space, and recovering spacecraft and crew safely.

Youngest of the Mercury Seven

The final flight of Project Mercury took place in May 1963. The youngest of the Original Seven, astronaut Gordon Cooper, went on to become the first American to fly in space for more than a day during this mission.

Leroy Gordon Cooper Jr. was born in 1927 and served in the Marine Corps in 1945 and 1946. He was commissioned in the U.S. Army after attending the University of Hawaii.

He was called to active duty in 1949 and completed pilot training in the U.S. Air Force. He was a fighter pilot in Germany from 1950 to 1954 and earned a bachelor's degree at the Air Force Institute of Technology in 1956. He served as a test pilot at Edwards Air Force Base in California until he was selected as an astronaut for Project Mercury. Cooper flew Mercury-Atlas 9, the last Mercury mission, which was launched on May 15, 1963. He called his capsule Faith 7, the number indicating his status as one of the Original Seven astronauts.

Conducts 11 experiments

 Longer than all of the previous Mercury missions combined. Cooper had enough time in his hands to conduct 11 experiments. These included monitoring radiation levels, tracking a strobe beacon that flashed intermittently, and taking photographs of the Earth.

When Cooper sent back black-and-white television images back to the control centre during his 17th orbit, it was the first TV transmission from an American crewed spacecraft. And even though there were plans for Cooper to sleep as much as eight hours, he only managed to sleep sporadically during portions of the flight. After 19 orbits without a hitch, a faulty sensor wrongly indicated that the spacecraft was beginning re-entry. A short circuit then damaged the automatic stabilisation and control system two orbits later. Despite these malfunctions and the rising carbon dioxide levels in his cabin and spacesuit. Cooper executed a perfect manual re-entry.

Lands without incident Cooper had clocked 34 hours and 20 minutes in space, orbiting the Earth 22 times and covering most of the globe in the process. This meant that he could practically land anywhere in the globe, a potential pain point that the U.S. State

Department was nervous about. In fact, on May 1, 1963, the country's Deputy Under Secretary fuel, venting gas that made the spacecraft roll, and more in what felt like a never-ending series during their eight-day mission. They, however, completed 122 orbits, travelling over 5.3 million km in 190 hours and 56 minutes, before safely making their way back to Earth.

After accumulating more than 225 hours in space, Cooper served as the backup command pilot of Gemini 12, which was launched in November 1966, and the backup command pilot for Apollo 10 in May 1969. By the time Cooper left NASA and retired from the Air Force in July 1970, human beings had set foot on the moon, further vindicating the Mercury and Gemini projects that Cooper had been involved with.

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Sound can only travel through a solid, liquid or gas and not through vacuum. As there is near complete vacuum in space, sound cannot travel and be heard through the ears like on Earth. Other forms of electromagnetic radiation including radio waves, however, can travel through vacuum. When astronauts are in a space shuttle or a space station, they can speak normally there are enough air particles to vibrate and take the sound to their ear drum. But when they are conducting a spacewalk, they need a special device to communicate with each other The helmets of astronauts are fitted with a device which converts the sound waves generated by their speech into radio waves and transmits them to other astronauts. When the headset of another astronaut receives the radio waves, it translates the signal into the sound form. The same principle is used to send and receive messages from Earth.

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Constellations are the 88 recognized patterns and groups of stars. These groups and patterns are usually associated with mythology. Today, constellations are not only the groups of stars, but now refers to the entire region of the sky that it takes up.

Asterisms are groups of stars that do not form their own constellations, but instead, are inside of constellations. The Big Dipper is an example of this. The Big Dipper is an asterism inside of the constellation Ursa Major. So I believe that asterisms are smaller than the constellations that they're in, but not necessarily bigger than all constellations. 

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An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept then the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux.

Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky.

The patterns of stars seen in asterisms are not necessarily a product of any physical association between the stars, but are rather the result of the particular perspectives of their observations. For example the Summer Triangle is a purely observational physically unrelated group of stars, but the stars of Orion's Belt are all members of the Orion OB1 association and five of the seven stars of the Big Dipper are members of the Ursa Major Moving Group. Physical associations, such as the Hyades or Pleiades, can be asterisms in their own right and part of other asterism at the same time.

Credit : Wikipedia 

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The smallest constellation is Crux, the Southern Cross. A small group of four bright stars that forms a Latin cross in the southern sky, Crux is visible from latitudes south of 25 degrees north and completely invisible in latitudes above 35 degrees north (in the United States, roughly north of Texas).

Originally it was part of the constellation Centaur, but became its own constellation during the 16th century when it was used as a valuable navigation tool by explorers. Its area is calculated at about 68 square degrees.

Blue-white ? Crucis (Acrux) is the most southerly member of the constellation and, at magnitude 0.8, the brightest. The three other stars of the cross appear clockwise and in order of lessening magnitude: ? Crucis (Mimosa), ? Crucis (Gacrux), and ? Crucis (Imai). ? Crucis (Ginan) also lies within the cross asterism. Many of these brighter stars are members of the Scorpius–Centaurus association, a large but loose group of hot blue-white stars that appear to share common origins and motion across the southern Milky Way.

Crux contains four Cepheid variables, each visible to the naked eye under optimum conditions. Crux also contains the bright and colourful open cluster known as the Jewel Box (NGC 4755) on its eastern border. Nearby to the southeast is a large dark nebula spanning 7° by 5° known as the Coalsack Nebula, portions of which are mapped in the neighbouring constellations of Centaurus and Musca.

Credit : Wikipedia 

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Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees, and also the longest at over 100 degrees. Its southern end borders Libra and Centaurus and its northern end borders Cancer. It was included among the 48 constellations listed by the 2nd century astronomer Ptolemy. Commonly represented as a water snake, it straddles the celestial equator.

Despite its size, Hydra contains only one moderately bright star, Alphard, designated Alpha Hydrae. It is an orange giant of magnitude 2.0, 177 light-years from Earth. Its traditional name means "the solitary one". Beta Hydrae is a blue-white star of magnitude 4.3, 365 light-years from Earth. Gamma Hydrae is a yellow giant of magnitude 3.0, 132 light-years from Earth.

Hydra has one bright binary star, Epsilon Hydrae, which is difficult to split in amateur telescopes; it has a period of 1000 years and is 135 light-years from Earth. The primary is a yellow star of magnitude 3.4 and the secondary is a blue star of magnitude 6.7. However, there are several dimmer double stars and binary stars in Hydra. 27 Hydrae is a triple star with two components visible in binoculars and three visible in small amateur telescopes. The primary is a white star of magnitude 4.8, 244 light-years from Earth. The secondary, a binary star, appears in binoculars at magnitude 7.0 but is composed of a magnitude 7 and a magnitude 11 star; it is 202 light-years from Earth. 54 Hydrae is a binary star 99 light-years from Earth, easily divisible in small amateur telescopes. The primary is a yellow star of magnitude 5.3 and the secondary is a purple star of magnitude 7.4. N Hydrae (N Hya) is a pair of stars of magnitudes 5.8 and 5.9. Struve 1270 (?1270) consists of a pair of stars, magnitudes 6.4 and 7.4.

The other main named star in Hydra is Sigma Hydrae (? Hydrae), which also has the name of Minchir, from the Arabic for snake's nose. At magnitude 4.54, it is rather dim. The head of the snake corresponds to the ?shlesh? Nakshatra, the lunar zodiacal constellation in Indian astronomy. The name of Nakshatra (Ashlesha) became the proper name of Epsilon Hydrae since 1 June 2018 by IAU.

Hydra is also home to several variable stars. R Hydrae is a Mira variable star 2000 light-years from Earth; it is one of the brightest Mira variables at its maximum of magnitude 3.5. It has a minimum magnitude of 10 and a period of 390 days. V Hydrae is an unusually vivid red variable star 20,000 light-years from Earth. It varies in magnitude from a minimum of 9.0 to a maximum of 6.6. Along with its notable color, V Hydrae is also home to at least two exoplanets. U Hydrae is a semi-regular variable star with a deep red color, 528 light-years from Earth. It has a minimum magnitude of 6.6 and a maximum magnitude of 4.2; its period is 115 days.

Hydra includes GJ 357, an M-type main sequence star located only 31 light-years from the Solar System. This star has three confirmed exoplanets in its orbit, one of which, GJ 357 d, is considered to be a "Super-Earth" within the circumstellar habitable zone.

Credit : Wikipedia 

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There are 88 modern constellations recognized by the International Astronomical Union (IAU). The list of the modern constellations was adopted by the IAU in 1922. The constellation boundaries as we know them today were set in the late 1920s. 36 modern constellations lie principally in the northern celestial hemisphere, while 52 are found in the southern sky.

The list of the modern constellations and the abbreviations used for them were produced by American astronomer Henry Norris Russell and approved by the IAU in May 1922. Russell’s list corresponded to the constellations listed in the Revised Harvard Photometry star catalogue, published by Harvard College Observatory in 1908. The constellation boundaries were drawn by Belgian astronomer Eugène Delporte and officially adopted in 1928.

The 88 modern constellations have different origins. Most of them are roughly based on the 48 ancient constellations catalogued by the Greek astronomer Claudius Ptolemy of Alexandria in his Almagest, an ancient astronomical treatise written in the 2nd century CE. These constellations are mostly associated with figures from Greek mythology. They include Andromeda, Cassiopeia, Perseus, Pegasus, Hercules, Orion, Ursa Major, Ursa Minor, Canis Major, Canis Minor, Eridanus, and the 12 zodiac constellations.

However, Ptolemy did not create these constellations. They were already well-known to observers long before his time. Even though they are called Greek constellations, they were not necessarily created by the Greeks. Depictions of some of the ancient constellations or the asterisms they are known for go back to prehistoric times and their creators are unknown.

Fifty of the modern 88 constellations are based on the Greek ones. Only one of Ptolemy’s constellations – Argo Navis – is no longer in use. Once the largest constellation in the sky, Argo Navis represented the ship of Jason and the Argonauts. It was divided into three smaller constellations – Carina, Puppis and Vela – by the French astronomer Nicolas-Louis de Lacaille in the 18th century. The three smaller constellations remain in use.

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Geostationary Operational Environmental Satellites (GOES) are satellites placed in Earth's orbit to observe the weather on the planet's surface.

The Geostationary Operational Environmental Satellite Program (GOES) is a joint effort of NASA and the National Oceanic and Atmospheric Administration (NOAA).

The GOES system currently consists of GOES-13, operating as GOES-East, in the eastern part of the constellation at 75 degrees west longitude and GOES-15, operating as GOES-West, at 135 degrees west longitude. The GOES-R series will maintain the two-satellite system implemented by the current GOES series. However, the locations of the operational GOES-R satellites will be 75 degrees west longitude and 137 degrees west longitude. The latter is a shift in order to eliminate conflicts with other satellite systems. The GOES-R series operational lifetime extends through December 2036.

These spacecraft help meteorologists observe and predict local weather events, including thunderstorms, tornadoes, fog, hurricanes, flash floods and other severe weather. In addition, GOES observations have proven helpful in monitoring dust storms, volcanic eruptions and forest fires.

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The first woman to travel in space was Soviet cosmonaut, Valentina Tereshkova. On 16 June 1963, Tereshkova was launched on a solo mission aboard the spacecraft Vostok 6. She spent more than 70 hours orbiting the Earth, two years after Yuri Gagarin’s first human-crewed flight in space.

Tereshkova was born on 6 March 1937 in the village of Bolshoye Maslennikovo in central Russia. Her mother was a textile worker, and her father was a tractor driver who was later recognised as a war hero during World War Two. At the time of his death on the Finnish front, Tereshkova was only two years old. 

After leaving school, Tereshkova followed her mother into work at a textile factory. Her first appreciation of flying was going down rather than up when she joined a local skydiving and parachutist club. It was her hobby of jumping out of planes that appealed to the Soviets' space programme committee. On applying to the cosmonaut corps, Tereshkova was eventually chosen from more than 400 other candidates. 

Tereshkova received 18 months of severe training with the Soviet Air Force after her selection. These tests studied her abilities to cope physically under the extremes of gravity, as well as handle challenges such as emergency management and the isolation of being in space alone. At 24 years old, she was honourably inducted into the Soviet Air Force. Tereshkova still holds the title as the youngest woman, and the first civilian to fly in space. 

While Tereshkova remains the only woman to have flown solo in space, her mission was a dual flight. Fellow cosmonaut Valeriy Bykovsky launched on Vostok 5 on 14 June 1963. Two days later, Tereshkova launched. The two spacecraft took different flight paths and came within three miles of each other. The cosmonauts exchanged communications while making 48 orbits of Earth, with Tereshkova responding to Bykovsky via her callsign ‘Seagull’. During the flight, the Soviet state television network broadcast a video of Tereshkova inside the capsule, and she spoke with the Russian Premier Nikita Khrushchev over the radio. 

In her later life, Tereshkova was decorated with prestigious medals and has held several prominent political positions both for the Russian and global councils. Before the collapse of the Soviet Union, she was an official head of State and was elected a member of the World Peace Council in 1966. 

Today, she holds the position of Deputy Chair for the Committee for International Affairs in Russia. She also remains active within the space community and is quoted as suggesting that she would like to fly to Mars - even if it were a one-way trip. 

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When the Moon passes between Sun and Earth, the lunar shadow is seen as a solar eclipse on Earth. When Earth passes directly between Sun and Moon, its shadow creates a lunar eclipse. Lunar eclipses can happen only when the Moon is opposite the Sun in the sky, a monthly occurrence we know as a full Moon. Lunar eclipses can happen only when the Moon is opposite the Sun in the sky, a monthly occurrence we know as a full Moon. But lunar eclipses do not occur every month because the Moon's orbit is tilted five degrees from Earth's orbit around the Sun, so most of the time the Moon passes above or below the shadow. Without the tilt, lunar eclipses would occur every month.

Lunar and solar eclipses occur with about equal frequency. Lunar eclipses are more widely visible because Earth casts a much larger shadow on the Moon during a lunar eclipse than the Moon casts on Earth during a solar eclipse. As a result, you are more likely to see a lunar eclipse than a solar eclipse.

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A comet has two tails. One is a dust tail pushed by light from the sun. Wired Science blogger Rhett Allain uses physics to explain how light can push on matter.

There are two tails because there are two ways the comet can interact with the sun. Everyone thinks about light coming from the sun. However, there is also the solar wind. The solar wind is really just charged particles (like electrons and protons) that escape from the sun due to their high velocities. These charged particles then interact with the ionized gas produced from the comet.

The other tail is due to an interaction with the dust produced by the comet and the light from the sun. Really, it is this interaction that I want to talk about.

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The nucleus is the solid core of a comet consisting of frozen molecules including water, carbon monoxide, carbon dioxide, methane and ammonia as well as other inorganic and organic molecules — dust. According to ESA the nucleus of a comet is usually around 10 kilometers across or less.

Comets are separated into three distinct parts called the tail, nucleus and the coma which ensures its workability. Comets work in the sense that they tend to be more explicit when they come closer to the source of illumination, the Sun. The tail of a comet is made up of three other parts, the ion tail, the hydrogen envelope, and the dust tail. All these are also vital for the movement of the comet both to and from the sun as indicated below.

The nucleus of a comet is made up of ice, gas, dust, and rocks. It is found right at the center of the head of a comet. The nucleus of a comet is often frozen. The part which is occupied by the gas in the comet’s nucleus is made up of carbon dioxide, the carbon monoxide, ammonia, and methane.

The comet’s area which is made up of the nucleus encompasses between 0.6 to around 6 miles. At times, it is even more than this distance. The nucleus, following this combination of materials, carries the most mass of the comet. The nucleus of a comet is also regarded as one of the darkest objects ever witnessed in the space.

Credit : Earth eclipse

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Coma. As a comet gets closer to the sun, the ice on the surface of the nucleus begins turning into gas, forming a cloud around the comet known as the coma. According to science website howstuffworks.com the coma is often 1,000 times larger than the nucleus. Outside the coma is a layer of hydrogen gas called a hydrogen halo which extends up to 1010 meters in diameter. The solar wind then blows these gases and dust particles away from the direction of the Sun causing two tails to form. These tails always point away from the Sun as the comet travels around it. One tail is called the ion tail and is made up of gases which have been broken apart into charged molecules and ions by the radiation from the Sun. Since the most common ion, CO+ scatters the blue light better than red light, to observers, this ion tail often appears blue.

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The current number of known comets is: 3,743. Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. They range from a few miles to tens of miles wide, but as they orbit closer to the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. This material forms a tail that stretches millions of miles.

Comets are cosmic snowballs of frozen gases, rock, and dust that orbit the Sun. When frozen, they are the size of a small town. When a comet's orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the Sun for millions of miles. There are likely billions of comets orbiting our Sun in the Kuiper Belt and even more distant Oort Cloud.

Credit : NASA science 

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