Posted on by John Carl Villanueva

What are Plate Boundaries?

In Plate Tectonic Theory, the lithosphere is broken into tectonic plates, which undergo some large scale motions. The boundary regions between plates are aptly called plate boundaries. Based upon their motions with respect to one another, these plate boundaries are of three kinds: divergent, convergent, and transform.

Divergent Boundaries:

Divergent boundaries are those that move away from one another. When they separate, they form what is known as a rift. As the gap between the two plates widen, the underlying layer may be soft enough for molten lava underneath to push its way upward. This upward push results in the formation of volcanic islands. Molten lava that succeeds in breaking free eventually cools and forms part of the ocean floor.

Some formations due to divergent plate boundaries are the Mid-Atlantic Ridge and the Gakkel Ridge. On land, you have Lake Baikal in Siberia and Lake Tanganyika in East Africa.

Convergent Boundaries:

Convergent boundaries are those that move towards one another. When they collide, subduction usually takes place. That is, the denser plate gets subducted or goes underneath the less dense one. Sometimes, the plate boundaries also experience buckling. Convergent boundaries are responsible for producing the deepest and tallest structures on Earth.

Among those that have formed due to convergent plate boundaries are K2 and Mount Everest, the tallest peaks in the world. They formed when the Indian plate got subducted underneath the Eurasian plate. Another extreme formation due to the convergent boundary is the Mariana Trench, the deepest region on Earth.

Transform Boundaries:

Transform boundaries are those that slide alongside one another. Lest you imagine a slippery, sliding motion, take note that the surfaces involved are exposed to huge amounts of stress and strain and are momentarily held in place. As a result, when the two plates finally succeed in moving with respect to one another, huge amounts of energy are released. This causes earthquakes.

The San Andreas fault in North America is perhaps the most popular transform boundary. Transform boundary is also known as transform fault or conservative plate boundary.

Movements of the plates are usually just a few centimeters per year. However, due to the huge masses and forces involved, they typically result in earthquakes and volcanic eruptions. If the interactions between plate boundaries involve only a few centimeters per year, you could just imagine the great expanse of time it had to take before the land formations we see today came into being.

You can read more about plate boundaries here in Universe Today. Here are the links:

Here are the links of two more articles from USGS:

Here are two episodes at Astronomy Cast that you might want to check out as well:

Sources:
Plate Boundaries
http://pubs.usgs.gov/gip/dynamic/understanding.html

Posted on by Fraser Cain

Destruction of Earth

Planet Killer
Artist's conception of an asteroid hitting Earth.

[/caption]
Want to destroy the Earth? It’s harder than it sounds. That’s because the Earth is held together by the mutual gravity of 5.97 x 1024 tonnes of rock and metal. In order to blast the Earth apart, you would need to introduce more energy than the gravitational energy holding the whole planet together.

Think about it, if you wanted to bring about the destruction of Earth, you can’t just fly in your orbiting death star and fire a turbo laser at the planet. You might melt a little spot, but it’s not going to cause the planet to detonate like it did in Star Wars. Add up the mutual gravitational attraction of every atom in the Earth, and that’s how much energy you would need coming out of your laser. A laser powerful enough could vaporize the rock and metal and let it escape out into space. Keep that laser firing for billions of years and it should do the trick.

Another possibility would be to strike the Earth with an asteroid large enough to smash the planet. We’ve been hit by millions of asteroids in the past, and one was even thought to have formed the Moon. It would take an object the size of Mars slamming into Earth at more than 11 km/s to actually shatter the planet.

Instead of burning it, or smashing it, you could change the Earth’s orbit into a downward spiral into the Sun. After a few million years the planet would be burned up and destroyed by the Sun. Problem solved. In order to actually shift the Earth’s orbit, you would need to move a heavy asteroid so that it gently nudges the Earth into a spiraling orbit.

Of course, you could just bring an equivalent amount of antimatter, and let the Earth and anti-Earth collide together. The entire Earth would be annihilated in a heartbeat, leaving a flash of energy. Earth destroyed, problem solved.

But in the end, the Earth will likely be destroyed when it’s swallowed up by the Sun in about 7 billion years. When the Sun runs out of fuel, it will expand in size, becoming a red giant star. Astronomers agree it will swallow up Mercury and Venus, but they aren’t sure if it will get so large that it reaches the Earth. But whatever happens, the surface of the Earth will be scorched.

If that doesn’t completely destroy the Earth, you’ll need to wait trillions of years for the planet to get sucked into some black hole. And if that never happens, it might take 10100 years for the atoms that make up the Earth to decay into pure energy.

Then, the destruction of Earth will be complete.

This is a just a taste of the monumental amount of work it would take to bring about the destruction of Earth. Perhaps the best article every written on the subject is over here at Things of Interest.

You should also read Phil Plait’s book, Death from the Skies, which looks at all the different ways the Universe is trying to kill us.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded a two-part episode of Astronomy Cast about the End of Everything (including the Earth). Here’s part 1, and here’s part 2.

Reference:
NASA

Posted on by John Carl Villanueva

VY Canis Majoris

VY Canis Majoris. The biggest known star.
Size comparison between the Sun and VY Canis Majoris, which once held the title of the largest known star in the Universe. Credit: Wikipedia Commons/Oona Räisänen

Of all known stars, the VY Canis Majoris is the largest. This red Hypergiant star, found in the constellation Canis Major, is estimated to have a radius at least 1,800 that of the Sun’s. In astronomy-speak we use the term 1,800 solar radii to refer to this particular size. Although not the most luminous among all known stars, it still ranks among the top 50.

Hypergiants are the most massive and luminous of stars. As such, they emit energy at a very fast rate. Thus, hypergiants only last for a few million years. Compare that to the Sun and similar stars that can keep on burning up to 10 billion years.

VY Canis Majoris a.k.a. VY CMa is about 4,900 light years from the Earth. This value, however, is just a rough estimate because it is too far for parallax to be used. Parallax is the most common method for measuring star distances. It is actually a special kind of triangulation method, i.e., similar to the one employed by engineers that make use of angles and a fixed baseline.

Some stars exist in pairs. These are called binary star systems. There are also multiple star systems. VY CMa, however, burns as a single star.

Being a semiregular variable star, VY Canis Majoris exhibits periodic light changes. Its period lasts for about 2,200 days.

The French astronomer Jerome Lalande is credited to be the first person to have recorded VY CMa. The entry in his star catalogue, dated March 7, 1801, lists it as a 7th magnitude star. Apparent magnitude is a unit of measurement for the brightness of a star as observed from Earth. The greater a star’s magnitude, the less bright it is.

Hence, a star with a magnitude of 1 (a.k.a. a 1st magnitude star) is considered among the brightest. There are also negative values, which denote even brighter bodies. Just to give you an idea where VY Canis Majoris stands in terms of brightness, the Sun (the brightest from our perspective) has an apparent magnitude = -26.73, while the faintest objects observable in the visible light spectrum (as detected from the Hubble Telescope) have magnitudes = 30.

It was once believed that VY CMa was a multiple star system. This was due to six discrete components that were measured by observers during the 19th century. Scientists eventually realized that the said discrete components were actually bright areas of the surrounding nebula.

You can read more about the VY Canis Majoris here in Universe Today. Here are the links:

Read more about it at NASA:

Here are two episodes at Astronomy Cast that you might want to check out as well:

Reference:
Wikipedia

Posted on by John Carl Villanueva

What Causes Tides?

The Earth is a water-dominated planet. (Image credit: Ian O'Neill)

Tides refer to the rise and fall of our oceans’ surfaces. It is caused by the attractive forces of the Moon and Sun’s gravitational fields as well as the centrifugal force due to the Earth’s spin. As the positions of these celestial bodies change, so do the surfaces’ heights. For example, when the Sun and Moon are aligned with the Earth, water levels in ocean surfaces fronting them are pulled and subsequently rise.

The Moon, although much smaller than the Sun, is much closer. Now, gravitational forces decrease rapidly as the distance between two masses widen. Thus, the Moon’s gravity has a larger effect on tides than the Sun. In fact, the Sun’s effect is only about half that of the Moon’s.

Since the total mass of the oceans does not change when this happens, part of it that was added to the high water regions must have come from somewhere. These mass-depleted regions then experience low water levels. Hence, if water on a beach near you is advancing, you can be sure that in other parts of the world, it is receding.

Most illustrations containing the Sun, Moon, Earth and tides depict tides to be most pronounced in regions near or at the equator. On the contrary, it is actually in these regions where the difference in high tide and low tide are not as great as those in other places in the world.

This is because the bulging of the oceans’ surface follows the Moon’s orbital plane. Now, this plane is not in line with the Earth’s equatorial plane. Instead, it actually makes a 23-degree angle relative to it. This essentially allows the water levels at the equator to seesaw within a relatively smaller range (compared to the ranges in other places) as the orbiting moon pulls the oceans’ water.

Not all tides are caused by the relative positions of these celestial bodies. Some bodies of water, like those that are relatively shallow compared to oceans, experience changing water levels because of variations in the surrounding atmospheric pressure. There are also other extreme situations wherein tides are manifested but have nothing to do with astronomical positioning.

A tidal wave or tsunami, for example, makes use of the word ‘tide’ and actually exhibits rise and fall of water levels (in fact, it is very noticeable). However, this phenomena is caused entirely by a displacement of a huge amount of water due to earthquakes, volcanic eruptions, underwater explosions, and others. All these causes take place on the Earth’s surface and have nothing to do with the Moon or Sun.

A thorough study of tides was conducted by Isaac Newton and included in his published work entitled Philosophiæ Naturalis Principia Mathematica.

We have some related articles here that may interest you:

There’s more about it at NASA. Here are a couple of sources there:

Here are two episodes at Astronomy Cast that you might want to check out as well:

Sources:
Princeton University
NASA
NOAA

Posted on by John Carl Villanueva

Famous Earthquakes

Earthquakes are among the most devastating forces of nature. What we have are seven of the world’s most famous earthquakes, chronologically listed below. Not all included here are necessarily the strongest (in terms of magnitude) but they made the headlines when they hit. Here they are:

Shaanxi Earthquake of 1556

– This was the deadliest quake ever recorded. It claimed the lives of about 830,000 people. At that time, most inhabitants in the affected areas were living in Yaodongs or artificial caves. They were buried alive when the huge tremors caused the cliffs in which these caves were located in, to collapse.

San Francisco Earthquake of 1906

– Although its tremors were also felt in Southern Oregon, it is the resulting fire in San Francisco that had a more devastating impact on the economy. Is has been often compared recently to Hurricane Katrina because of its similar economic bearing.

The Great Chilean Earthquake of 1960

– Like the one that hit Asia in 2004, this 9.5-rated quake resulted in a massive tsunami reaching up to as high as 10.7 meters. This magnitude is the highest recorded ever. Although the tsunami originated in Cañete, Chile, the waves raced north-westward to Japan and the Philippines, wreaking havoc there.

Great Alaska Earthquake of 1964

– With a magnitude of 9.2, it is the second strongest earthquake to be ever recorded. It caused tsunamis, landslides, and resulted in major landscape changes. Some places near Kodiak is said to have been raised 9.1 meters high, while those near Portage were dropped by 2.4 meters. Here are more articles about Alaska earthquakes.

Great Tangshan Earthquake of 1976

– This is the deadliest quake of the 20th Century, with the number of deaths hitting somewhere near 250,000. Weak building structures and the time this disaster struck (4 am) contributed a lot to that sickening number.

Bam Earthquake of 2003

– The death toll in this tremor reached over 26,000. Like the one in Tangshan, the use of poor construction materials was one of the leading culprits for the deaths. Most of the affected buildings were made of mud bricks.

Indian Ocean Earthquake of 2004

– The resulting tsunami that killed 230,000 people was caused by a subduction between the India and Burma plate. Its 30 m-high waves destroyed virtually everything in its path, making this quake not only one of the most famous earthquakes but also one of the famous natural disasters in history.

Excluding poor building infrastructure, we can see that high death tolls in these famous earthquakes result when the tremors are accompanied by tsunamis. This happens when the quake’s epicenter is found at the bottom of the ocean.

You can read more about famous earthqueakes here in Universe Today. Here are the links:

There’s more about it at USGS. Here are a couple of sources there:

Here are two episodes at Astronomy Cast that you might want to check out as well:

Sources:
http://en.wikipedia.org/wiki/1906_San_Francisco_earthquake
http://en.wikipedia.org/wiki/2006_Hawaii_earthquake
http://en.wikipedia.org/wiki/1556_Shaanxi_earthquake
http://earthquake.usgs.gov/earthquakes/world/events/1960_05_22.php
http://en.wikipedia.org/wiki/1964_Alaska_earthquake
http://en.wikipedia.org/wiki/1976_Tangshan_earthquake
http://en.wikipedia.org/wiki/2003_Bam_earthquake
http://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_and_tsunami

Posted on by John Carl Villanueva

Milankovitch Cycle

Graphic showing how changes in the Earth's eccentricity and tilt can lead to massive changes in maximum sunlight it receives, and therefore its climate.

Milankovitch cycles. Source: UCAR

A Milankovitch cycle is a cyclical movement related to the Earth’s orbit around the Sun. There are three of them: eccentricity, axial tilt, and precession. According to the Milankovitch Theory, these three cycles combine to affect the amount of solar heat that’s incident on the Earth’s surface and subsequently influence climatic patterns.

Eccentricity

The path of the Earth’s orbit around the sun is not a perfect circle, but an ellipse. This elliptical shape changes from less elliptical (nearly a perfect circle) to more elliptical and back, and is due to the gravitational fields of neighboring planets (particularly the large ones – Jupiter and Saturn). The measure of the shape’s deviation from being a circle is called its eccentricity.

That is, the larger the eccentricity, the greater is its deviation from a circle. Thus, in terms of eccentricity, the Earth’s orbit undergoes a cyclical change from less eccentric to more eccentric and back. One complete cycle for this kind of variation lasts for about 100,000 years.

Axial Tilt

We know the earth is spinning around its own axis, which is the reason why we have night and day. However, this axis is not upright. Rather, it tilts at angles between 22.1-degrees and 24.5 degrees and back. These angles are measured between the angle of the axis to an imaginary line normal (perpendicular) to the Earth’s plane of orbit. A complete cycle for the axial tilt lasts for about 41,000 years.

Greater tilts mean that the hemispheres closer to the Sun, i.e., during summer, will experience a larger amount of heat than when the tilt is less. In other words, regions in the extreme upper and lower hemispheres will experience the hottest summers and the coldest winters during a maximum tilt.

Precession

Aside from the tilt, the axis also wobbles like a top. A complete wobble cycle is more or less 26,000 years. This motion is caused by tidal forces from the Sun and Moon.

Precession as well as tilting are the reasons why regions near and at the poles experience very long nights and very long days at certain times of the year. For example, in Norway, the Sun never completely descends beneath the horizon between late May to late July.

The Milankovitch Cycles are among the arguments fielded by detractors of the Global Warming concept. According to them, the Earth’s current warming is just a part of a series of cyclical events that take thousands of years to complete, and hence cannot be prevented.

You can read more about milankovitch cycle here in Universe Today. Here are the links:

There’s more about it at USGS and NASA. Here are a couple of sources there:

Here are two episodes at Astronomy Cast that you might want to check out as well:

References:
NASA Earth Observatory
NOAA Website

Posted on by Tammy Plotner

What Planets Are Visible Tonight?


Are you interested in knowing what planets are visible tonight? Almost every night of the year, some planet in our solar system can be spotted using either just your eyes, a pair of binoculars or a small telescope. Finding the planets is easy – but you just have to know how! Here’s a few simple lessons and some great links to helping you locate what planets you can see from your location on any given night…

Finding The Ecliptic Plane

eclipticJust as the Earth orbits the Sun, our Moon orbits the Earth in a clockwork fashion, along an imaginary path called the ecliptic plane. Why is knowing the sky position of the Moon and Sun important? Because the planets also orbit the Sun like clockwork on the same path – the ecliptic plane. Picture our solar system from above. In the center is our Sun and around it the planets move along their own race tracks. The planets close to the Sun orbit faster and their track is smaller, while outer planets move slower and their track is longer – this is Kepler’s law in action!

orreryVenus and Mercury speed past Earth’s position several times a year, passing in front of or behind the Sun. Earth is running with them, but on a longer track. On the outside tracks are Mars, the asteroid belt, Jupiter, Saturn, Uranus, Neptune and planetoid Pluto – all on the same flat plane. There are times when the Sun is positioned between Earth and the outer planets. They are still holding their position on their tracks, but we simply cannot see them. When the inner planets pass the Earth, or the Earth passes the outer planets, something very extraordinary happens – retrograde motion. How does it work? Picture yourself in a moving car coming up on another vehicle. As you approach, the other car seems to slow down, stand still and then move backwards. It’s a rather simple explanation, but it’s how retrograde motion works!

Observing the Planets

mercury_and_venusThe two inner planets – Mercury and Venus – are closer to the Sun than Earth. This means we will always see them just before the Sun rises, or just after the Sun sets. The ring of the inner planet’s orbit is much smaller than Earth’s, and they will only appear a short distance above the horizon. At times, when Mercury reaches its greatest elongation, it is bright enough to be seen easily with just your eyes, but it helps to use binoculars. And we all know that Venus outshines every star in the sky! Mercury apparitions usually happen in the evening sky three times a year and three times in the morning. Usually, the best time to see Mercury is just after sunset near the vernal equinox. Since it orbits the Sun in just 88 days, it moves fast, so don’t delay your observations! If you observe Mercury through a telescope, you’ll see it enter a slim crescent phase as it passes between us and the Sun – just like our Moon! Another planet that goes through phases is inner Venus. Orbiting the Sun more slowly along its longer track every 244 days, we see Venus for months at a time instead of just days. It will appear in the evening for about six weeks as it comes out from behind the Sun, growing higher and brighter each night until it reaches a point between the Earth and Sun. This is when you’ll see a crescent phase in the telescope! Venus will then disappear and a week or two later it will return just before the Sun rises. It will stay in the morning sky for about 9 months until it once again switches its course back to the evening.

MarsViewing_Dec11-12As we move outward along the ecliptic plane, we pass Earth and move on to Mars. Since its orbital track around the Sun is slightly longer than ours, there will be extended periods of time when Mars is visible. Do you remember retrograde motion? When the Earth catches up with Mars it will appear to slow down on its path across the sky as we approach it, stand still as we come alongside, and move the other way as we pass it. A Mars’ viewing year will begin when it first makes its appearance in the morning on the opposite side of our solar system. There it will stay until Earth’s orbit begins to catch up with it and it rises 6 minutes earlier each day. As the cycle continues, it won’t be long until Mars reaches opposition, meaning it (or any outer planet) rises precisely the same time as the Sun sets. As we pass, it becomes brighter and larger – but never the same size as our Moon.

Jupiter_Saturn_dennismammana2Next up is Jupiter – orbiting the Sun once every twelve years. Jupiter is visible most of the year, beginning in the morning until sidereal time carries it to the early evening hours. With a much slower orbit of 30 years, graceful old Saturn will be viewable much of the year as well – waltzing slowly along the ecliptic plane. Far away Uranus and Neptune and planetoid Pluto can viewed whenever their respective constellations are visible. Retrograde motion also happens with the outer planets, but the process is much slower. Just remember… the planets all follow the same rule – the ecliptic plane. Do you remember what else also follows that same rule? That’s right… the constellations of the zodiac. You will always see the planets in relationship with those twelve constellations!

What Planets Are Visible Tonight?

724We can observe the planets with our eyes, binoculars, or a telescope and many planets are viewable during many different times of the year. There are many on-line resources that can tell you when and where they will appear, as well as many periodicals which chart the planets’ paths. Would you like some resources to help you along your planetary discovery path? Then here are a few of my favorites:

See The Planets Tonight!

free_2776077It is very easy, even from light polluted areas, to follow Mercury, Venus, Mars, Jupiter and Saturn with just your eyes alone. When they are visible, they shine brightly enough to follow their movements without any special equipment. The outer planets are naturally dimmer because they are much further away. With a pair of binoculars as an aid, it’s also easy to see Uranus and Neptune, but they aren’t very big or very bright. Planetoid Pluto is so incredibly small and distant that it takes at least a medium-sized telescope and careful work over many nights with a star chart to identify properly. Now… Get out there and get started! Once you have gained confidence in the position of the ecliptic, it won’t be difficult to watch the action of the planets from night to night. They are easy to recognize and it won’t be long before you’ll be identifying them – not by luck – but as an amateur astronomer!

“Planetary Line-Up” photo courtesy of Dennis Mammana (APOD).

Posted on by John Carl Villanueva

What are Divergent Boundaries?

Pangaea
Pangea animation

Divergent boundaries are one of the bi-products of plate tectonics. As the name implies, divergent boundaries are formed when two adjacent tectonic plates separate, i.e., when they diverge.

When tectonic plates start to diverge, the linear feature formed is called a rift. Sometimes, the gap widens and sometimes it stops. When the gap eventually widens, it then evolves into a rift valley. Divergent boundaries that occur between oceanic plates produce mid-oceanic ridges.

In places where molten lava is able to move up and fill the gap, volcanic islands are eventually formed. Molten lava that rises eventually cools and forms part of the ocean floor.

One divergent boundary is the Mid-Atlantic Ridge, found at the bottom of the Atlantic and is the longest mountain range in the world. That’s right, the longest mountain range is hidden from our view. Imagine how astonished crew members of the HMS Challenger were when they discovered the massive rise underneath them. The Challenger expedition was dedicated to scientific discoveries the became foundations of oceanography. The Mid-Atlantic Ridge was observed by the HMS Challenger in 1872.

The record for the slowest divergent boundary in the world goes to Gakkel Ridge between the North American Plate and the Eurasian Plate in the Arctic Ocean. Its annual rate of separation is less than one centimeter – that’s about half as fast the rate your fingernails grow. Robotic submersibles belonging to the AGAVE expedition discovered microbial communities of over a dozen new species on this ridge.

Although not as common, rift valleys can also be formed on land. One example is the Basin and Range province in Nevada and Utah. The world’s largest freshwater lakes such as Siberia’s Lake Baikal and East Africa’s Lake Tanganyika are found in rift valleys.

One of the favorite natural laboratories for the study of divergent plate boundaries is Iceland. The Mid-Atlantic Ridge runs beneath Iceland and as the North American Plate moves westward while the Eurasian Plate moves eastward, Iceland will slowly be sliced in half. When water rushes in to fill the widening gap, this huge island of ice will form two smaller islands.

How far can divergent boundaries go? Well if we look at a time frame of 100 to 200 million years, we can easily spot the Atlantic Ocean. What is believed to have been a tiny inlet of water between the formerly merged Europe, Africa, and Americas has now evolved into this vast expanse of water.

You can read more about divergent boundaries here in Universe Today. Here are the links:

There’s more about it at USGS. Here are a couple of sources there:

Here are two episodes at Astronomy Cast that you might want to check out as well:

Sources:
Plate Boundaries
http://pubs.usgs.gov/gip/dynamic/understanding.html
http://en.wikipedia.org/wiki/Divergent_boundary
http://geology.com/nsta/divergent-plate-boundaries.shtml

Posted on by John Carl Villanueva

Astronaut Helmet

Astronaut Suit
lunar-spacesuits. Image credit: NASA

The astronaut helmet protects its wearer from micrometeoroids, solar ultraviolet as well as infrared radiation. It is made up of the protective shell, neck ring, vent pad and feed port. Protection from radiation is actually provided by the Extravehicular Visor Assembly, which is fitted over the helmet.

A typical astronaut helmet like those worn in the Apollo missions is made of highly strengthened polycarbonate. Polycarbonate is a high impact-resistant plastic that you can also find in bulletproof glass and exterior automotive parts.

The neck ring mentioned above is a vital component in the pressure sealing feature of the astronaut’s outfit and attaches the helmet to the suit. The vent pad, which is fastened to the rear, has a recess that provides ventilation flow related functions. The feed port, on the other hand, supports the water and feed probes as well as the purge valve.

Today’s helmets have a built-in cam which allow us to see what they’re doing up there.

Both the helmet and suit provide protection from the dangerously low pressure of outer space. Without them, internal pressure in the astronaut’s body will push blood vessels and tissue outward.

Contrary to what Hollywood has portrayed in sci-fi films like Arnold Schwarzenegger’s Total Recall wherein bodies blow up when exposed to the vacuum of space, the effects are less sensational though. Nevertheless, full exposure to vacuum can still be harmful – lung damage being one of the side effects.

A lot of inconveniences accompany the wearing of an astronaut helmet. For example, you can’t just take it off to scratch a simple itch on your nose. To remedy this, a velcro patch is stuck on the inside to serve as a scratcher.

Also, since the helmet is fastened to the suit, astronauts who forget this end up facing its inner walls when they turn their heads. This can be quite annoying when they’d have to see panel switches above or at the sides from where they’re initially facing.

The problem gets even more complicated when they’re sitting. Since they’re strapped on their seats, astronauts can’t just lean back to face upward. If they want to turn their heads, they’d have to grab the helmet so they can make it turn to the desired direction.

Want to know what the most inconvenient predicament is? Space sickness or Space Adaptation Sickness (SAS) can strike even the most seasoned pilots, so imagine yourself as an astronaut having to puke right in the middle of a spacewalk. Still want to be the next Buzz Aldrin?

You can read more about astronaut helmet here in Universe Today. Here are the links:

There’s more about it at NASA. Here are a couple of sources there:

Here are two episodes at Astronomy Cast that you might want to check out as well:

Source: NASA

Posted on by Nicholos Wethington

Who was the First Monkey to go into Space?

Albert II in preparation for his historic flight. Image Credit: NASA

There are many brave astronauts that have participated – and even given their lives – in the quest to put human beings into space. But before those astronauts had a chance to take flight, there was a long line of other creatures that paved the way for human spaceflight. The first living beings were fruit flies, which were sent up along with some seeds of corn in 1947 to test the effects of radiation on DNA. The container of flies flew aboard a V2 rocket to a height of 106 miles (171 km), and the capsule was recovered with the flies alive and well.

The first monkey to be sent successfully into space was Albert II, a male rhesus monkey, who made it to a height of 83 miles (134 km) on June 14, 1949. Albert II was carried aboard a V2 rocket as well, though his fate was not as lucky as that of the fruit flies: a problem with the parachute on the recovery capsule sadly led Albert II to his death from the force of the impact upon landing.

Albert II was preceded by Albert, whose capsule only made it to a height of 39 miles (63km) on June 11, 1948. Albert did not last long, and possibly suffocated even before his capsule left the ground. Space officially begins at 100 km above the surface of the Earth, and this height is called the Karman Line. After Albert II made it into space, a number of other monkeys, named Albert III, IV, and V all flew aboard rockets, though none survived the flight, either dying on impact or during the flight.

All of the monkeys were anesthetized during their missions, and implants and sensors – as well as cameras on later missions – allowed scientists to study the effects of weightlessness and radiation at high altitudes on living creatures. Without the sacrifice of these animals, there would have been much loss of human life during the space program.

The first monkeys to survive the flight into space were two monkeys named Able and Miss Baker. They flew to a height of 360 miles (580 km) on May 28, 1959 aboard a Jupiter rocket. Their capsule landed 1700 miles (2736 km) downrange from the Eastern Space Missile Center at Cape Canaveral, Florida, and they were successfully recovered. To read more about this historic event, check out our story commemorating the 50th anniversary of the flight.

For more information on the history of animals in space, NASA has a brief synopsis here, and a much more detailed version here.

Source: NASA