My Science School

Launched on April 17, 1967, Surveyor 3 was the third engineering flight of the Surveyor series and the second in the series to achieve a soft landing on the moon. It was based on Surveyor 3's surface sampling tests that it was concluded that the lunar surface could hold the weight of an Apollo lunar module

The Apollo 11 mission will remain in the collective consciousness of human beings forever. This is because it was the first time we humans managed to set foot on our natural satellite, the moon.

It is important to remember that this was made possible due to a number of missions that preceded this one. Among these was the Surveyor 3 spacecraft which proved beyond doubt that an Apollo lunar module could indeed safely land on the moon's surface.

The third engineering flight of the Surveyor series, this spacecraft was the first to carry a surface-sampling instrument that could reach up to 1.5 m from the lander and dig up to 18 cm. Unlike its predecessors, Surveyor 3 began its mission from a parking orbit around Earth on April 17, 1967.

Bouncing to a stop

While it became the second in the series after Surveyor 1 to achieve a soft landing on the moon three days later on April 20, it was far from smooth. As highly reflective rocks confused the landers descent radar, the main engine did not cut off at the correct moment during the descent to the lunar surface.

This meant that Surveyor 3 bounced off the moon, not once but twice-first to a height of 10 m and then again to a height of 3 m. It was third time lucky for Surveyor 3 as it landed softly in the southeastern region of Oceanus  Procellarum.

With its worst behind it. Surveyor 3 set out to do what it was sent to do. Within an hour after landing, the spacecraft began transmitting the first of over 6,000 TV pictures of the surrounding areas.

Similar to wet sand

The most important phase of the mission included deployment of the surface sampler for digging trenches, manipulating lunar material, and making bearing tests. Based on commands from Earth, the probe was able to dig four trenches, performing four bearing tests and 13 impact tests.

The results from these experiments were the most important aspect of this mission. The scientists were able to conclude that lunar soil's consistency was similar to that of wet sand and that it would be solid enough to bear an Apollo lunar module when it landed.

The start of May saw the first lunar nightfall following the arrival of Surveyor 3. The spacecraft's solar panels stopped producing electricity and its last contact with Earth was on May 4. While Surveyor 1 could be reactivated twice after lunar nights, Surveyor 3 could not be reactivated when it was attempted 336 hours later during the next lunar dawn.

Tryst with Apollo 12

 That, however, wasn't the last of what we heard about Surveyor 3. Four months after the huge success of Apollo 11, NASA launched Apollo 12 in November 1969. The lunar module of Apollo 12 showcased pinpoint landing capacity as the precise lunar touchdown allowed the astronauts to land within walking distance of the Surveyor 3 spacecraft. During their second extra vehicular activity on November 19, astronauts Charles Conrad, Jr. and Alan L. Bean walked over to the inactive Surveyor 3 lander and recovered parts, including the camera system and the soil scoop.

Just like moon rocks, these were returned to Earth for studying, as they offered scientists a unique chance to analyse equipment that had been subjected to long-term exposure on the moon's surface. The studies of the parts showed that while Surveyor 3 had changed colour due to lunar dust adhesion and exposure to the sun, the TV camera and other hardware showed no signs of failure.

While NASA placed some of the Surveyor 3 parts into storage along with moon rocks and soil samples, the remaining parts found home elsewhere. Even though NASA treats them as lunar samples and not artefacts, they are greatly valued when gifted or loaned out, both to museums and individuals.

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The sudden energy expulsion from the Sun can have its impact on Earth - from causing auroras to disrupting radio communications. Extreme eruptions can even affect electricity grids on Earth. In 1972, geomagnetic storms triggered the detonation of dozens of sea mines off the Vietnam coast. In 1989, a severe solar storm caused by multiple CMES took out Quebec's (a Canadian province) entire electricity grid for over nine hours. One of the most severe storms. dubbed the Carrington Event, occurred in 1859. It was marked by an intense brightening of auroras and reports of telegraph systems malfunctioning. Today, a similar event would have far worse implications for technology.

The United States National Oceanic and Atmospheric Administration on Monday issued a warning against an enormous geomagnetic storm caused by a strong solar flare. According to the department, the solar flare could cause massive disruption to power grids and affect spacecraft and satellites. The phenomenon is also expected to cause the northern lights to be visible in New York.

The massive solar storm set to hit earth today could potentially cause major disruption. A G2, or moderate warning was issued based on the geomagnetic storm watch readings. According to experts, the possible effects of the sudden flash due to the increased brightness from the Sun 93 million miles away could be felt from the Earth.

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An aurora is nothing but a beautiful light show in the sky. One can witness auroras near the North and the South Poles. If you witness it at the North Pole, it is aurora borealis or northern lights. At the South Pole, it is called aurora australis or southern lights. Auroras are caused by the interaction of charged particles from the Sun with atoms in the Earth's upper atmosphere. When there is a solar storm, the Sun sends out gusts of charged solar particles across space. If the Earth is in the path of the particle stream, our planet's magnetic field and atmosphere react. As the particles pass through Earth's magnetic shield, they mingle with atoms and molecules of oxygen, nitrogen and other elements, resulting in the spectacular display of light in the sky. Last month's G3 geomagnetic storm brought bright, dynamic auroras that were visible as south as Pennsylvania, lowa and Oregon.  

The Sun sends us more than heat and light; it sends lots of other energy and small particles our way. The protective magnetic field around Earth shields us from most of the energy and particles, and we don't even notice them.

But the Sun doesn't send the same amount of energy all the time. There is a constant streaming solar wind and there are also solar storms. During one kind of solar storm called a coronal mass ejection, the Sun burps out a huge bubble of electrified gas that can travel through space at high speeds.

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Geomagnetic storm is a brief disturbance in Earth's magnetic field and atmosphere caused by bursts of radiation and charged particles emitted from the Sun. Geomagnetic storms are divided into 5 classes from G1 to G5, where G1 is the weakest and G5 the strongest. A magnetic storm is a period of rapid magnetic field variation. It can last from hours to days.

The Sun sometimes emits a strong surge of solar wind called a coronal mass ejection. This gust of solar wind disturbs the outer part of the Earth's magnetic field, which undergoes a complex oscillation. This generates associated electric currents in the near-Earth space environment, which in turn generates additional magnetic field variations -- all of which constitute a "magnetic storm."

Occasionally, the Sun's magnetic field directly links with that of the Earth. This direct magnetic connection is not the normal state of affairs. When it occurs, charged particles traveling along magnetic field lines can easily enter the magnetosphere, generate currents, and cause the magnetic field to undergo time dependent variation. 

Sometimes the Sun emits a coronal mass ejection at a time when the magnetic field lines of the Earth and Sun are directly connected. When these events occur, we can experience a truly large magnetic storm.

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A Coronal Mass Ejection (CME) is an explosive outburst of solar wind plasma from the Sun. The blast of a CME typically carries roughly a billion tons of material outward from the Sun at speeds on the order of hundreds of kilometers per second. A CME contains particle radiation (mostly protons and electrons) and powerful magnetic fields. These blasts originate in magnetically disturbed regions of the corona, the Sun's upper atmosphere - hence the name. Solar flares are often accompanied by coronal mass ejections, which are large expulsions of plasma and magnetic field from the corona, or Sun's outermost layer. They explode into space at very high speeds. Cannibal coronal mass ejections happen when fast-moving solar eruptions overtake earlier eruptions in the same region of space, sweeping up charged particles to form a giant, combined wavefront.

 Most CMEs form over magnetically active regions on the "surface" of the Sun in the vicinity of sunspots. CMEs are often associated with solar flares, another type of explosive "solar storm". However, CMEs and solar flares don't always go together, and scientists aren't completely sure how the two phenomena are related. CMEs are much more common during the "solar max" phase of the sunspot cycle, when sunspots and magnetic disturbances on the Sun are plentiful.

CMEs travel outward through the Solar System. Some are directed towards Earth, though many others miss our planet completely. The radiation storms which are a part of CMEs can be hazardous to spacecraft and astronauts. If a strong CME collides with Earth's magnetosphere, the disturbance can trigger a series of events that sends a burst of particle radiation into Earth's upper atmosphere. As the radiation crashes into gas molecules in Earth's atmosphere, it causes them to glow... creating the magnificent light shows of the auroras (the Northern Lights and Southern Lights).

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The solar cycle is an approximately 11-year cycle experienced by the Sun. During the solar cycle, the Sun's stormy behavior builds to a maximum, and its magnetic field reverses. Then, the Sun settles back down to a minimum before another cycle begins. About every 11 years, the Sun's magnetic field does a flip. In other words, the north pole becomes the south pole, and vice versa. Scientists use sunspots to track solar cycle progress.  Much of the Sun's tempestuous nature comes from its core. At its core is dense, electrically charged gas. Electrically charged gas is a special form of matter called a plasma. This roiling, boiling plasma generates the Sun's powerful magnetic field. Like Earth's magnetic field, the Sun's magnetic field has a north pole and a south pole. On the Sun, however, the magnetic fields are much messier and more disorganized than on Earth. The beginning of a solar cycle a solar minimum, when the Sun has the least sunspots and when the magnetic field is at its weakest. Over time, solar activities such as solar flares or coronal mass ejections increase. These can spew light, energy, and solar material into space. Solar cycles are being tracked since 1755 and we are currently in the 25th phase. The previous solar cycle ran from 2008 to 2019. We are currently escalating towards solar maximum (due to take place around July 2025), when the solar magnetic field is at its strongest.

Sunspots are areas of particularly strong magnetic forces on the Sun's surface. They appear darker than their surroundings because they are cooler. Even so, scientists have discovered that when there are lots of sunspots, the Sun is actually putting out MORE energy than when there are fewer sunspots. During solar maximum, there are the most sunspots, and during solar minimum, the fewest.

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Sometimes a sudden, rapid, and intense variation in brightness is seen on the Sun. That is a solar flare. A solar flare is a sudden explosion of electromagnetic energy caused by reorganising of magnetic field lines near sunspots. (Sunspots are dark blotches that form on the surface of the Sun, where the magnetic fields are particularly strong). The flares are seen as bright areas on the Sun and they can last from minutes to hours. We typically see a solar flare by the photons (or light) it releases, at almost every wavelength of the spectrum. The current solar flares are just part of the Solar Cycle 25, which began in December 2019.

Even though the solar flare stays close to the Sun (relatively speaking), the material thrown in to space by these explosions is radioactive. It is potentially dangerous to spacecraft and especially to people in space. Solar flares emit radiation across virtually the entire electromagnetic spectrum, from radio waves at the long wavelength end, through optical emission to x-rays and gamma rays at the short wavelength end. This radiation can corrode equipment, overload cameras or MICAS, and expose humans to dangerous levels of radiation.

Solar flares are classified as A, B, C, M or X according to the peak flux (in watts per square metre, W/m2) of 1 to 8 Ångströms X-rays near Earth, as measured by XRS instrument on-board the GOES-15 satellite which is in a geostationary orbit over the Pacific Ocean.

The A & B-class are the lowest class of solar flares. They are very common and not very interesting. C-class solar flares are minor solar flares that have little to no effect on Earth. Only C-class solar flares which are long in duration might produce a coronal mass ejection but they are usually slow, weak and rarely cause a significant geomagnetic disturbance here on Earth.  M-class solar flares are what we call the medium large solar flares. They cause small (R1) to moderate (R2) radio blackouts on the daylight side of the Earth.  X-class solar flares are the biggest and strongest of them all. On average, solar flares of this magnitude occur about 10 times a year and are more common during solar maximum than solar minimum. Some (mostly stronger) solar flares can launch huge clouds of solar plasma into space which we call a coronal mass ejection. When a coronal mass ejection arrives at Earth, it can cause a geomagnetic storm and intense auroral displays.

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Sunlight only takes 490 seconds (8 minutes 10 seconds) to reach Earth. And then at the most distant point, it takes 507 seconds (8 minutes 27 seconds) for sunlight to make the journey. However, this time is variable because the earth is constantly orbiting the sun on a course which is elliptical, ie uneven.The distance between the earth and the sun is 149.6 million kilometres (that’s 92.95 million miles). The speed of light is 299,792,458 metres per second (299,792.458 kilometres per second).  Once they reach the surface and escape they travel fast. But they are made via fusion reactions right at the sun’s core and VERY slowly work their way out.

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Proxima Centauri, closest star to our sun.  The star Proxima Centauri isn’t visible to the eye, but it’s one of the most noted stars in the sky. That’s because it’s part of the Alpha Centauri star system, home to three known stars and the closest stellar system to our sun. Of the three stars in Alpha Centauri, scientists believe Proxima is closest to our sun, at 4.22 light-years away. Astronomers have discovered two planets for Proxima so far. It also has massive solar flares and might even be the source of a mysterious radio signal. 

‘Usually, when stars are so close to Earth, they appear bright in our sky. Consider the star Sirius, for example, in the constellation Canis Major. Sirius is the brightest star in Earth’s sky, at just 8.6 light-years away. So why isn’t Proxima Centauri, at 4.22 light years away, even brighter? Instead of being bright, Proxima isn’t visible at all the the eye alone.

And the reason is that Proxima Centauri is so small. It’s what’s called a red dwarf star, one of the most common sorts of stars in our Milky Way galaxy. It contains only about an eighth of our sun’s mass. Faint red Proxima Centauri is only 3,100 Kelvin (5,100 degrees F or 2,800 C) in contrast to 5,778 K for our sun. So Proxima is 500 times less bright than our sun.

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Sirius, also known as the Dog Star or Sirius A, is the brightest star in Earth's night sky. The name means "glowing" in Greek — a fitting description, as only a few planets, the full moon and the International Space Station outshine this star.

Because Sirius is so bright, it was well-known to the ancients. But the discovery of a companion star, Sirius B, in 1862 surprised astronomers. The star that you can see with the naked eye is called Sirius A, or sometimes just Sirius. 

Sirius B is 10,000-times dimmer than Sirius, according to NASA(opens in new tab). It's so dim, and therefore so difficult to see from Earth, that astronomers couldn't estimate its mass until 2005, thanks to data from the Hubble Space Telescope.

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