Soyuz TMA Re-Entry

Today's trivia dives into the detail of how Astronauts return from space.

On March 1st 2016 Scott Kelly (NASA) and Mikhail Korniyenko (RSC) returned to Earth in the Soyuz-TMA spacecraft. How does an astronaut return from orbit in this spacecraft?

Soyuz TMA spacecraft

The Soyuz TMA-M (transport, modified, anthropometric) is the latest in a very slow evolution of Russian human-rated spacecraft.

Soyuz TMA-17 before docking

Primary Functions

• Carry up to 3 crew into a variety of orbits
• Orbital transit
• Docking
• De-orbit and re-entry
• Soft landing

Its design philosophy is based around automation. Most of the main tasks required for re-entry are automatic. It can also be fully controlled from ground control stations. Crew can override as required, for example if they encounter an emergency. A lot of its design is focused around many levels of redundancy. Automated systems have usually two backup systems and include some kind of reasonable contingency if all were to fail.

Artistic image of the 17 July 1975 Apollo Soyuz Test Program (ASTP) the first docking of a Russian and American spacecraft showing comparable scale of the Apollo and Soyuz spacecraft

The first Soyuz was developed at the same time as the American Apollo program as part of a secretive Soviet lunar mission which was eventually halted due to a number of reasons. This same craft has undergone three main design evolutions to spacecraft used today.

Its use as a crew transportation and return spacecraft for space stations was first proposed by the Russians as the Automatic Crew Return Vehicle for both the joint NASA/RSC project on the Mir space station and the International Stance Station. If the station was damaged by space debris or a medical evacuation was required, the Soyuz would be used for these tasks. With its 110+ manned launches it has an extensive track record.

Undock

Soyuz TMA-03M spacecraft (left) eases toward its docking with the Russian-built Mini-Research Module 1

Once the crew are onboard and suited up in their pressure suits, they will go through various checklists to prepare for the flight. This takes in excess of three hours, which may include time verifying there are no drops in pressure within Soyuz.

View from the on board computer system pilots view with information overlay

Once released from the station, springs inside the docking ring push the craft away from the station. The Soyuz is only able to use its reaction control thrusters once it is far enough (20m) away from the station to prevent covering the station in liquid propellant.

De-Orbit burn

The de-orbit burn is also automatic. Once the spacecraft position is accurately known, the computer calculates the angle and duration of burn to get the required landing trajectory to a pre-determined landing site.

This burn is critical as it determines the angle of descent into the atmosphere:

• Too shallow and it will bounce off the atmosphere without showing down, resulting in overheating.
• Too steep and the crew will experience too much deceleration force (in excess of 10g) which may be fatal for the crew.

Soyuz is made up of three modules, at the front is the Orbital Module, in the middle is the Descent Module and at the back is the Service Module which includes the solar panels

Once the de-orbit burn is complete, the Orbital and Service modules are jettisoned. Explosive bolts fire which push the jettisoned modules away from the descent module. They will burn up on the atmosphere on reentry. If for some reason the modules do not separate correctly, the Soyuz is designed so aerodynamic forces will break the modules apart in any case.

30 minutes later the spacecraft will cross the Kármán line at 100km and come into contact with enough atmosphere to start re-entry.

Re-Entry

Seen from the International Space Station, the Soyuz TMA-05M descent module begins to re-enter the Earth's atmosphere, leaving a plasma trail as the Expedition 33 crew streaks toward a pre-dawn landing on the steppe of Kazakhstan.

During re-entry the capsule will decelerate from orbital velocity (17,000mph) down to speeds where the parachutes can be deployed. This deceleration is the result of the capsule crashing into the atmosphere. The heat shield of Soyuz is rated to withstand the incredible temperatures of re-entry, however the shape is also crucial as well:

"If the reentry vehicle is made blunt, air cannot "get out of the way" quickly enough, and acts as an air cushion to push the shock wave and heated shock layer forward away from the vehicle. Since most of the hot gases are no longer in direct contact with the vehicle, the heat energy would stay in the shocked gas and simply move around the vehicle to later dissipate into the atmosphere." - Wikipedia

The re-entry is also completely automatic. The computer will use reaction control thrusters to create a steering effect, enough to keep it aligned with its target landing site. Should the computer fail, or an emergency arise such as depressurisation, the backup re-entry process will start a ballistic re-entry. This re-entry is faster because it is steeper but induces up to 8g of force on the crew.

Re-Entry as seen from the inside window of Soyuz Buzz Feed

Landing

Once the descent has slowed enough, the parachutes can be deployed. First two drogue chutes, followed by a main chute. This slows the capsule down to the required landing speed.

Around the same time the heat shield, and external window covers are jettisoned.

Just before landing 6 soft landing solid rockets fire to improve the landing which an astronaut still describe as "feeling like you are being hit by a truck".

During the early Soviet missions the landing site was less predictable. The cosmonaut would expect to be greeted by team parachuted in to assist. Now days helicopters and ground support vehicles arrive at the predetermined landing site and are in constant communication with the capsule as it lands.

Soyuz TMA-01M spacecraft shortly after the capsule landed

References:

• NASA Overview
• Detail on Soyuz
• PDF on Re-entry Detail
• YouTube - ESA Landing Sequence for crew training
• YouTube - Roscosmos State Corporation
• YouTube - Re-Entry Footage from Apollo 11 1969
• YouTube - Re-Entry Footage from Orion 2015

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Super Weapons of Star Wars

This trivia is entirely based on the facts as presented by the Star Wars universe and in places a bit of extra analysis. It is purely fiction and as such might sound a bit made up.

Note: To help make sense of the amounts of energy used I've helpfully added in equivalent Twinkie sizes. That is, the energy in Joules can be converted to the an equivalent energy in calories which can be scaled to an equivalent size of Twinkie. We don't have Twinkies in the UK, this probably doesn't help that much.

DS-1 Orbital Battlestation (Death Star I) and Death Star II

The second Death Star around Endor Full Size

Both the first Death Star I and the second Death Star II where improbably large structures, intended with the sole purpose of destroying all that opposed the Empire. Able to destroy fleets of ships and indeed entire planets. Both battlestations had the capability to move both within system, and via hyperspace to other star systems.

• Radius: 60km, 80km
• Crew: ~ 1.5 million, ~ 2.4 million
• Propulsion: In system Ion drives, Hyperdrives to travel between systems

Power source

In both Death Stars a Hyper Matter Annihilator reactor is used, though much larger in the second.

Hypermatter is matter that exists in hyperspace, and when constrained in real space, and accelerated to the speed of light it gives off immense amounts of energy. Combined with massive amounts of reactant fuel to generate the power required to power the Death Star. The energy generated by the power source is comparable to the output of a main sequence star.

A main sequence star like our own outputs 3 x 10t26 J per second = Twinkie ~800km in length, from Land's End in Cornwall to Newcastle in the midlands.

Schematic of the internal components of the Death Star Full Size

Super Laser

In both Death Stars, the super laser is the main feature of the station. Large amounts of the internal space are dedicated to the support machinery required to power and operate the weapon.

The laser focusing crystals are known as Kyber Crystals. These are the very same crystals used as the focusing crystals in light sabres, however those are tiny compared to the ones used in the Death Star. Finding and transporting them without some pesky Jedi blowing them up proved to be an arduous task for the Empire.

The firing of the super laser appeared to be dependent on its energy output. For example destroying a planet required a 24 hour charge period. Destroying a starship only required a 3 minute charge.

The second Death Star was designed by the same designer as the first Death Star, albeit a clone.

"A second, more powerful battle station designed by the same engineer who was killed by Darth Sidious for the first station's weak spot, and then cloned to make the second station better and without the fatal flaw of the first."

Energy Required to Destroy Alderaan

Research Paper

Needless to say, there are those in the scientific community which wondered the same question. One paper takes us through the equations and energy outputs required to destroy an Earth sized planet.

The basis of the paper covers the Gravitational Binding equation. That is, the energy required to take apart a planet, piece by piece sending each piece away from the planet until there is nothing left.

For a planet the size of Earth (and Aldaraan) this is 2.25 ⨉ 10t32 Joules = A Twinkie ~ 80,000km in length, twice the circumference of Earth.

The key finding of the paper states that because the power source of the Death Star outputs so much power, destroying a planet the size of Aldaraan is entirely possible. However a planet the size of Jupiter would require multiple firings.

StarKiller Base

Super weapons are definitely getting bigger as the series goes on source

This brings us to the First Orders StarKiller Base. The First Order where obviously impressed with the earlier Empires efforts at building large super weapons, but they clearly thought that the Empire had not set their sights high enough. So instead the converted an entire planet to the task of being a super weapon.

• Dimensions: Ice Planet
• Crew: Lots
• Propulsion: Can move between systems, within system is assumed for targetting

This thing is ridiculous.

It is unclear when construction on it started, but we can be reasonably certain that the First Order did not exist until after the fall of the Empire. It is therefore unlikely that construction started before the need for the super weapon existed. Either way the effort required to hollow out the core of a planet and replace that with the machinery required to support the super laser is incredible.

Clearly the mantle of the planet has been replaced Full Size

Super Laser:

The film demonstrates its ability to destroy planets. Five of them ... simultaneously... from a distant star system.

The offered explanation for the system is based on a number of functions:

• Solar extraction: The ability to draw the hydrogen from the star and use that to drive a fusion reactor, or capture the thermal energy from the surface of the star
• Storage: Converting and compressing the energy of the star into Dark Matter which can be stored within the planet (size of star versus size of planet)
• Targeting: The weapon is fixed within the planet and would need to be at least vaguely aligned with the target star system many light years. The weapon is able to target multiple planets at the same time.
• Subspace: Prepartion of Subspace tunnels that will allow the energy beam to travel almost instantaneously from source to target star system. This uses an alternate dimension known as Subspace which is only possible to access with the energy levels produced by this super weapon.
• Firing Weapon: The firing sequence is described as "breaching the Dark Matter storage containment" which releases the stored energy. We know it makes a mess of the nearby trees.

Power Source

A main sequence star like our own gives off 3 ⨉ 10t26 Joules per second = Twinkie ~800km in length weighing twenty-two quadrillion, six hundred trillion tons. This is a huge amount of energy to work with.

"If all the hydrogen in the Sun were to be fused into helium, the energy equivalent of this would be 8.7 x 10t44 Joules." = Twinkie ~1,000,000,000km long which is approximately 25,000 times round the Earth. Enough to destroy four trillion Alderaan planets, not counting for energy costs of operating the planet. Reference.

That is indeed a big Twinkie.

Appendix: Hyperspace

Hyperspace in Star Wars is an alternate dimension where conventional space appears quite different. In hyperspace, real space and relative distances appear "wrinkled" such that with the correct course through hyperspace a vessel can travel the vast interstellar distances in considerably short times.

This relationship between hyperspace and real space is the reason for the development of known routes through hyperspace. Large mass objects (stars, planets, super weapons etc) cast "shadows" in hyperspace such that the navigation computer must avoid these objects. Failure to do so will result in the vessel being pulled out of hyperspace early. Near a star, this would be disastrous. In "IV:A New Hope" the Falcon is pulled out of hyperspace by the Death Star for this reason, the Death Star did not appear on their navigation computers maps.

The hyperdrive functioned by sending hypermatter particles to hurl a ship into hyperspace while preserving the vessels mass/energy profile, and required a functional hyperdrive motivator to do so. The vessel would then travel along a programmed course until it dropped back into realspace and arrive at its destination.

References:

• Scott Manly with Twinkies
• Scott Manly without Twinkies
• Twinkie Converter
• How to say really big numbers
• Size comparison

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February

In today's trivia we try and work out what that deal with February is:

• Why is this month shorter than the rest?
• Why is it used for the leap year offset?

Recreation of a Roman fasti, an official list of public days when official business could be conducted and celebrations would take place, based on the Roman calendar

Origins of the Months

Before we can answer those questions we need to dig a little into the history of calendars and where the Months of the Gregorian calendar come from.

Calendar of Romulus

To start, we need to go back as far as the formation of the Roman Empire. The first documented calendar we know they used was the Calendar of Romulus. A solar calendar in that it related to the progress of the Earth around the Sun, as opposed to a Lunar calendar which tracks progress of the Moon around the Earth.

This calendar is interesting for a number of reasons:

Martius (31 days)

Aprilis (30 days)

Maius (31 days)

Iunius (30 days)

Quintilis (31 days)

Sextilis (30 days)

September (30 days)

October (31 days)

November (30 days)

December (30 days)

This calendar consists of ten months and a total of 304 days. The remainder of the year, the winter months were not tracked by the calendar. Instead the calendar was started each year at the spring equinox occurring in the first month of the calendar.

This strikes me as particularly convenient as it resolves a common problem with early calendars. That of drift of the calendar against the seasons. Lunar calendars for example track the progress of the Moon each month. But a Lunar month is 29.5 days long (354 days) and so does not coincide with the solar year (365.2 days) so for a Lunar calendar to track the seasons, they need an offset month known as an intercalary month to be added each year to correct for the drift.

Finally we see that there are some months we recognise. The origins of all the months is not entirely clear but we can certainly see a few we recognise. The last six months indicate their positions in the calendar based on the Latin words quinque, sex, septem, octo, novem and decem.

Calendar of Numa

At some point during the reign of Numa Pompilius (715–673 BC) a refined version of this calendar was introduced. The Romans of the time considered even numbers to be unlucky, so they removed a day from each of the even numbered months (Aprilis, Iunis, Sextilis, September, November and December). Combined with the winter months there was enough days to define two extra months of January (29) and February (28). February being 28 days long was considered a suitable candidate for Februa the Roman festival of purification which we imagine is where its name comes from.

Ianuarius (29)

Februarius (28)

Martius (31)

Aprilis (29)

Maius (31)

Iunius (29)

Quintilis (31)

Sextilis (29)

September (29)

October (31)

November (29)

December (29)

This brings the total days to 355. This calendar would of course drift each year.

As mentioned above, the Romans added an intercalary month when it was thought necessary (every two years) to bring the calendar inline with the solar year. On a year when they added an intercalary month, February would end on the 23rd (Terminalia) and the month would month would be added. This extra month would be either 27 or 28 days (377 or 378 for the year).

The average of every two years would bring the calendar to 366 days a calendar year. This made for a more workable system.

That was until the Romans started using the intercalary month for political purposes. The position of Pontifex Maximus was responsible for setting the length of the intercalary month. The office of Pontifex Maximus was generally held by a member of a politically prominent family. It was a coveted position mainly for the great prestige it conferred on the holder. Since the term of office for a political official was determined by the calendar year, there are indications that the length of the year was open to debate.

For example, Julius Caesar made the year of his third consulship in 46 BC 445 days long.

Julian Calendar

In the same year, Julius Caesar, as Pontifex Maximus reformed the calendar in 46 BC. The new calendar became known as the Julian calendar. This calendar proved very successful as it was in use up until 1582 when the Pope Gregory mandated the use of the Gregorian calendar system.

Ianuarius (31)

Februarius (28)

Martius (31)

Aprilis (30)

Maius (31)

Iunius (30)

Quintilis (31)

Sextilis (30)

September (30)

October (31)

November (30)

December (30)

This gives a total of 365 days with a leap day added to February every four years which gives the Julian calendar an average of 365.25 days a year. This was only later improved upon by the Gregorian calendar in the West.

This system was primarily introduced because maintaining the intercalary month of the Numa calendar was proving both an administrative burden, and a political complexity which tended towards the average Roman some distance from the city not knowing the date. The last three years before the switch to the Julian calendar where remarked as "years of confusion".

After its introduction, it proved useful. Varro used it in 37 BC to fix calendar dates for the start of the four seasons, which would have been impossible only 8 years earlier. A century later, when Pliny dated the winter solstice to 25 December because the sun entered the 8th degree of Capricorn on that date, this stability had become an ordinary fact of life.

Gregorian Calendar

The final stop on this chronological tour is the Gregorian Calendar we are all familiar with which was established in 1582 by Pope Gregory XIII. It can be summarised as follows:

"Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is."

The calendar was a refinement to the Julian calendar amounting to a 0.002% correction in the length of the year. The motivation for the reform was to bring the date for the celebration of Easter to the time of the year in which it was celebrated when it was introduced by the early Church. Because the celebration of Easter was tied to the spring equinox, the Roman Catholic Church considered the steady drift in the date of Easter caused by the year being slightly too long to be undesirable. The reform was adopted initially by the Catholic countries of Europe. The last European country to adopt the reform was Greece, in 1923.

Conclusion

So to conclude, we can tell that calendars became hugely important in civilisations. The moment there was demand for agriculture, civic planning, trade and commerce etc there will be a demand for coordinating activities via a calendar. Every major civilisation has developed its own calendar system to help track the days and months of the solar year.

To answer the specific questions of February, we can now say it is the short month because of a combination of factors:

• Early calendars were lunar and so each month was roughly the same length
• Most calendars could not precisely follow the solar year
• The Roman calendars used the month of February to adjust the length of the year
• The Julian calendar also uses February for the leap year adjustment
• Which is why we still use February to track leap years in the Gregorian calendar.

References

• Roman Calendars
• Julian Calendar
• Gregorian Calendar

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Giant Crystal Caves

Today's trivia is all about the a mine in North Mexico known as the Naica Mina.

This mine was first opened in 1794, though only officially exploited in 1900. The mine is of interest commercially for its deposits of lead, zinc and silver, among other minerals which are still actively being extracted.

Before mining could start the mine has to be drained of water. The water level normally resides at a depth of 110m below sea level. This needed to be drained to a depth of 850m below sea level. A complex pumping system had to be developed to be able to do this and can extract 22,000 gallons of water per minute when turned on.

full size

In the year 2000 another system of three caves were discovered which contain some rather impressive crystals. We'll be talking specifically about the "Giant Crystal Cave", located at 290m below sea level. Some of these selenite crystals are immense. The cave's largest crystal found to date is 12m (39 ft) in length, 4m (13 ft) in diameter and weights 55 tons.

full size

Formation of the Crystals

The Naica mine lies on an ancient fault above an underground magma chamber below the cave.

The magma heats the ground water which was saturated with sulfide ions. Meanwhile cool oxygenated surface water comes into contact with the mineral saturated heated water, but the two did not mix due to the difference in their densities. The oxygen slowly diffused into the heated water and oxidized the sulfides into sulfates.

This creates an environment where hydrated sulfate gypsum can crystallize at an extremely slow rate of over the course of at least 500,000 years forming the enormous crystals found today.

The key to this process is the slow diffusion of oxygen from the cool, low density surface water into the hot, high density ground water.

Conditions in the Cave

Exploring the cave is particularly hazardous for humans. The ambient temperature is 58C (136F), and the humidity is close to 100%.

full size

This represents two significant risks to humans:

• Heat Exhaustion Unprotected from the heat, the human body cannot regulate its temperature quick enough in those sorts of temperatures. You would be sweating profusely if you found yourself stuck down there would ultimately pass out from the lack of water and sodium in your body.

• Breathing The air in this sort of temperature would be incredibly difficult. It would be likely that the in insides of your lungs would be cooler than the outside temperature. The humidity would start to condense inside your lungs leaving only a short time window for exploration.

A lot of infrastructure has been put in place to support exploration of the caves.

Before you can enter the caves you reach a staging area which is at a comfortable 41C. This staging area hosts all the support equipment required to venture into the actual crystal caves. This includes freezers to store the cooling suits, video monitoring equipment and paramedics on standby in the event of a medical emergency.

Camera equipment has to be allowed to come up to temperature before it can be used in the caves, otherwise it would risk fogging up.

Refrigeration Suits

To explore the caves, researchers had to develop specific suits to help protect the wearers from the conditions in the caves.

full size

Ptolomea Suit

The initial suit design created by Giovanni Badinno consisted of multiple layers:

• Insulated layer: protects the wearer from direct skin contact with the icy cooling layer
• Cooling layer: Ice tube covered layer to protect the entire body from the` excessive temperature.
• Outer layer: Rugged overalls to reduce heat transfer by radiation and protect from jagged environment

This suit allows the wearer an hour of effective research time in the caves however it comes at the drawback of being heavy and restricts mobility for the wearer.

View of the inner cooling layer of the suit, total weight 22kg

Lightweight Suit

The researchers were able to optimise the design trading off some exploration time for a more mobile suit design. Instead of complete body coverage in cooling ice tubes, they opted for a cooling layer which just covered the torso in frozen gel packs. This allows more mobility for the arms and legs with an exploration time of around 30 minutes.

The lighter suit system weighs 8kg in total

Breathing System

Breathing in the cave is difficult without breathing apparatus. For this they developed a backpack based system. Replaceable frozen metal bottles are stored in the backpack with a fan which blows warm air over the bottles. This is then fed into a face mask which allows the wearer access to cool air to breath.

Fitted facemask

Inside the backpack of the air cooling system, frozen metal bottles act as the cool source

Future of the cave

Once the mining operations in the cave end, it is expected that they will turn off the water pumping system, allowing the thermal water level to rise and once again fill the the entire cave system. The facilities to support exploration of the crystal caves and the caves themselves would become inaccessible and will resume their slow growing process.

References:

• Official Website
• Suit Detail
• Video about suit design
• Account from researcher
• Overview
• Informative Video

Quiz of 2015

Today’s trivia is in the form of a quiz. It is entirely based on Friday Trivia presented in 2015. There is no score for this quiz, merely an opportunity for some afternoon entertainment.

Does the Japanese high speed train service "shinkansen" mean "bullet train"?

No, shinkansen (新幹線) means "New Branch Line". The phrase "bullet train" was an English nickname used around the 1960's to describe high speed train services like the shinkansen.

Reference

The trilobite is named because of three parts of its body, which three parts are we talking about?

The trilobite gets its name from structure of its head. Not the head (cephalon), segmented thorax and tail (pygidium), but rather the right pleural lobe, axial lobe and left pleural lobe of the head.

Reference

Where in an ants nest might be a good place to sleep if you were a worker ant?

Workers tend to sleep in one of three locations, the chamber floor, ceiling or side of chamber. Those that sleep on the chamber floor were most likely to be woken by other workers passing by. Seemingly the best place to sleep was the side of the chamber.

Reference

We estimate it weighs about a pound

Which falls faster in a vacuum? A Sandwich Sandwich scotch egg, or a feather?

The mighty Sandwich Sandwich scotch egg is not a meal to be treated lightly. When modelled as a bowling ball we can estimate its behaviour in near vacuum conditions with the following animation as provided by the BBC.

One observation we concluded in this thought experiment was that given the mass of the Sandwich Sandwich scotch egg, its own gravitational pull might draw the feather closer to it over a long enough distance.

Reference

What purpose was WD-40 originally developed for?

WD-40 (Water Displacement formula 40) was originally developed as an easily applied oil coating to the paper thin balloon fuel tank of the Atlas SM-65 ballistic missile.

Reference

Who catches who whilst buzzing around in the territorial airspace of a lampshade?

The common house fly has a territorial behaviour of flying around a known landmark in a room. The airspace patrolled by musa domestica is 50cm by 50cm by 25cm and the males of the species will chase any other fly that enters that air space.

This proves an effective selection mechanism for this species as males of the same species will evade capture, whereas females of the same species will generally be caught. Because eggs are not laid near landmarks in the room (lampshade) we can conclude that this is a specific mating behaviour.

Reference

When making tea is it milk first or milk last?

There were a number of conclusions in this particular trivia. In summary, if you are making tea in a teapot, then adding the milk first was preferable. If you are making tea in a mug, then milk after appeared to be the answer. It should be noted that this was a highly contentious subject which we only just managed to discuss without a full scale war breaking out.

Reference

Of the many techniques for opening bananas, which is the technique favored by monkeys?

Amusingly of the many ways to open a banana, the one preferred by monkeys is to use their teeth to rip open the skin before eating the fruit inside.

Reference

How does the Venus Flytrap (dionaea muscipula) tell the difference between a fly and a rain drop?

Each lobe (leaf that captures an insect) has a number of small hairs. The trap triggers when the hairs are triggered with enough time between them. The plant is successfully able to differentiate between rain fall and a fly which is feeding on the leaf. The leaves are coated in a sweet liquid designed to attract insects and spiders.

Reference

Did Thomas Crapper invent the flush toilet?

No, he was a successful businessman in the 20th century selling toilets. Toilets and sanitation have been known about since antiquity. However the flush toilet specifically is believed to have been invented in 1596 by Sir John Harington in his publication "A New Discourse of a Stale Subject, Called the Metamorphosis of Ajax".

Reference

Three Gifts

What would you do with the three gifts of the nativity?

Without delving into the labyrinthine theological complexities of the Nativity, what would one do if they received a delivery of gold, frankincense and myrrh?

Gold

You would probably want to get it assayed and valued.

Gold purity is measured as the karat which is a measure of the purity of the substance. Precious metals are often alloyed with other metals to give them different properties such as increasing the durability of the metal.

For example Sterling Silver consists of 92.5% silver and 7.5%, by mass, of other metals, usually copper.

The measure of the karat is used for gold, and is an indication of percentage of gold. It is out of 24, with the highest being 24/24, or 24 karat gold.

If you are lucky, the gold will be in a convenient format, like bullion coin or gold bar.

These are known formats, issued by countries with known weights and purity values.

For example in order to be called a gold bullion, the coin must be stamped and of regulated weight and at one point must have been legal tender. For example a gold United Kingdom Sovereign weights exactly 7.3224g.

Gold bars, known as Good Delivery bars are less regulated due to their shape. Without certificates of authenticity would likely need to be assayed to work out its exact composition and certificates issued.

Regardless, in one of these formats you could then genuinely walk into a suitable bank and sell said gold. It is currently worth about $33,000/kg.

However if it is not in one of the aforementioned formats, then you would need to go a lot further to refine or convince someone of its worth.

Frankincense

Frankincense also known as olibanum is an incense which has particular significance in Jewish tradition, used at the time as an offering, incense and in perfume.

The word 'frankincense' comes from the Frankish Crusaders which introduced it to Europe. However it was known to ancient civilisations like the Greeks and Chinese, being primarily an export from South Arabia.

The actual material is a dried aromatic resin which comes from the Boswellia tree. The resin is collected much the same way as rubber by carving grooves in the trunk and collecting the resin.

The flowers of the Boswellia tree

If you received some now you might use it as an incense (common in Eastern Orthodox Christian churches). It has uses in the perfume industry as well as medical research where it is being investigated for potential use in cancer research.

Myrrh

If you received myrrh, you would want to make sure you weren't getting muddled up with frankincense as they both look very similar, and are used in very similar ways. Traditionally used as a perfume, incense and medicine. Particularly as a medicine myrrh would have been useful for its antiseptic properties. In modern research it is again of interest for its potential anti-cancer effects.

The resin is harvested from another arabian tree, the Commiphora myrrha tree.

Conclusion

In conclusion, if someone gave you the three gifts of the Nativity, you might wonder what was going on. One of them requires extensive paperwork and the other two literally grow on trees.

Eddie Izzard describing the Christmas Nativity - contains swearing Video

Sleep in Ants

Today’s trivia is about Ants, and in particular their sleep patterns.

Firstly we can confirm that Ants do sleep and exhibit demonstrable sleep behaviours.

We will dig further into the subterranean life of these invertebrates to understand more about their sleep patterns.

There is only a handful of research papers on sleep in Ants. (Bees are considerably more researched). The paper we are most interested in is this one:

Polyphasic Wake-Sleep Episodes in the Fire Ant Solenopsis Invicta

The research paper covers a particular species, Solenopsis Invicta famous for its stinging ability.

Sleep in Insects

Sleep in insects is particularly interesting because insects have quite different physiology. Another problem is how to actually determine sleep in insects:

Homeostasis: The balance between sleep and awake periods, sleep deprived flies are more sleepy during the day

Alertness: Insects which are sleeping are slow to respond to external stimulus

Circadian Rhythm: Insects that live above ground are likely to have periods of increased activity and periods of rest in line with a daily cycle, insects which live underground are generally polyphasic with no discernable circadian rhythm

Getting an Ant colony

How does one acquire an ant colony to study sleep patterns? Ant hives are constructed entirely underground with only thermal venting sections placed above ground.

Drip flotation method

In fire ants, the drip floatation method takes advantage of a flood-survival adaptation of the ants to accomplish this task. The key principle is that ants are so small and light that they are naturally buoyant. They also have a waxy coating which helps repel water and allows the entire colony to stay afloat when they cling together. Combined with their ability to self organise they can effectively float an entire colony on water.

• Dig up an ant colony and place it in a large bucket
• After 24 hours the ants will reestablish the structure of the colony with brood in chambers and tunnels to the surface excavated
• Talc powder is used on the sides of the container to prevent the ants climbing the sides.
• Water is dripped slowly into the bucket
• After 4-8 hours the water level rises slowly enough the the colony has gathered on the surface, brood and queens included
• Eventually the colony will form a raft, floating on the surface which can then be transferred to an artificial nest.

Sleep Patterns

Key observation about the sleep behavior as anticipated is that because they are a subterranean species they are not affected by day/night cycles, rather sleep patterns are determined by activity in the hive.

Workers

• Average 253 sleeps per day
• Each sleep about 1 minute
• Total 4.8 hours of sleeping a day

Workers tend to sleep in one of three locations, the chamber floor, ceiling or side of chamber. Those that sleep on the chamber floor were most likely to be woken by other workers passing by. Seemingly the best place to sleep was the side of the chamber.

Queens

• Average of 92 sleeps per day
• Each sleep about 6 minutes
• Total 9.6 hours of sleeping per day

Queens exhibited two observable sleep patterns:

Dozing: antenna extended, stationary, likely to be woken by contact from a worker.

Deep sleep: antenna tucked in close, stationary, unresponsive to external stimulus. Prone to random antenna movement during deep sleep.

Delightfully the queens would synchronise their sleep patterns so that they all would sleep at the same time, and woke up at the same time. They did this by huddling together when they slept, like hounds. When one started to stir the others would wake up as well.

Conclusion

The net result of this experiment found that at any given time there was on average 80% of the work force available to work on grooming, feeding or excavating sand. Queens in this species can live for 6 years, workers only one month.

The hive is always busy (hyper active) at attending to the needs of the Queens and buffering them from environmental effects which might be detrimental. This allows the queens to maintain a high reproductive efficiency and extend their longevity.

References

More about Fire Ants

Video of a sleeping Bee