Universe Today

September 2, 2009December 24, 2015 by Nancy Atkinson

LRO Sees Bouncing, Rolling Boulders on the Moon

Closeup of LROC image showing boulders that have rolled down the slope of Tsiolkovskiy Crater. Credit: NASA

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Think nothing ever happens on the Moon? New images from the Lunar Reconnaissance Orbiter Camera shows spectacular views of the famous Tsiolkovskiy Crater, and a close-up look reveals boulders that have rolled down the slopes of the crater. In the larger image, below, it is easy to see where the boulders came from by following their rolling, bouncing tracks. These are not small rocks by any means: the largest boulder in this image is about 40 meters wide – half as big as a soccer field! Seeing where the boulders originated from is a great clue to geologists reconstructing the local geology. What do they see here?

Tsiolkvoskiy Crater is 185 km in diameter, and is a great example of complex impact crater. It has a terraced rim, a central peak, and a floor flooded with mare basalts. Impact events release tremendous amounts of energy and result in very dynamic changes in the local landscape. Just after the initial impact, the central peak was uplifted from lower crustal rock, forming a giant mountain in the middle of the crater. That’s where the boulders rolled down the slopes, as pieces of the uplifted rock rolled down and accumulated at the base of the slope.

This is an easy way for explorers to find samples of the central peaks without having to climb the top. The Apollo 17 astronauts used this strategy as an easy way to sample nearby mountain tops without having to don any climbing gear!

Click the image for a larger “Zoomifiable” version.

The dark area in the lower right is the tip of enormous shadow cast by the central peak. Scroll north in the full image, and you will find the contact where the later-formed lavas pooled at the base of the peak. Even though the central peak formed before the mare, it has fewer craters due to its steep slope which tends to slump and slide erasing small craters. In this case, that’s an apparent violation of the rule that older surfaces have more craters!

Click here to see a zoomable look at Tsiolkovskiy Crater taken by the Apollo missions.

Source: LROC Journal

September 2, 2009December 24, 2015 by Nancy Atkinson

Do We Look Like This Edge-On?

Seen edge-on, observations of NGC 4945 suggest that this hive of stars is a spiral galaxy much like our own Milky Way. Credit: ESO

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Unfortunately, the Universe isn’t equipped with any three-panel dressing room mirrors, so we can’t see what our own Milky Way Galaxy looks like face on, or even from the side. But here’s a great new edge-on image of Galaxy NGC 4945, and many astronomers think this hive of stars closely resembles our own spiral galaxy with swirling, luminous arms and a bar-shaped central region. However, in sizing up this mirror-like image, does our black hole look that big? No, say astronomers from the European Southern Observatory. NGC 4945 has a brighter center that is likely home to a supermassive black hole bigger than the Milky Way’s, and it is devouring reams of matter and blasting energy out into space.

As NGC 4945 is only about 13 million light-years away in the constellation of Centaurus, a modest telescope is sufficient for skygazers to spot this remarkable galaxy.

James Dunlop, a Scottish astronomer, is credited with originally discovering NGC 4945 in 1826 from Australia.

For a closer view, click here to see a zoomable image of NGC 4945.

Today’s new portrait of NGC 4945 comes courtesy of the Wide Field Imager (WFI) instrument at the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile. NGC 4945 appears cigar-shaped from our perspective on Earth, but the galaxy is actually a disc many times wider than it is thick, with bands of stars and glowing gas spiraling around its centre. With the use of special optical filters to isolate the color of light emitted by heated gases such as hydrogen, the image displays sharp contrasts in NGC 4945 that indicate areas of star formation.

Other observations have revealed that NGC 4945 has an active galactic nucleus, meaning its central bulge emits far more energy than calmer galaxies like the Milky Way.

Scientists classify NGC 4945 as a Seyfert galaxy after the American astronomer Carl K. Seyfert, who wrote a study in 1943 describing the odd light signatures emanating from some galactic cores. Since then, astronomers have come to suspect that supermassive black holes cause the turmoil in the centre of Seyfert galaxies. Black holes gravitationally draw gas and dust into them, accelerating and heating this attracted matter until it emits high-energy radiation, including X-rays and ultraviolet light. Most large, spiral galaxies, including the Milky Way, host a black hole in their centres, though many of these dark monsters no longer actively “feed” at this stage in galactic development.

Source: ESO

September 2, 2009April 26, 2016 by Nancy Atkinson

Astronomers Find Most Distant Supermassive Black Hole Yet

Composite pseudo-color image of the QSO (CFHQSJ2329-0301). The RGB colors are assigned to z0; zr and i0-bands, respectively. The figures are north up, east left. Credit: Goto et al.

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A long time ago in a galaxy far, far away there was a supermassive black hole….. Astronomers from the University of Hawaii have spotted a giant galaxy surrounding the most distant supermassive black hole ever found. The galaxy, so distant that it is seen as it was 12.8 billion years ago, is as large as the Milky Way galaxy and harbors a supermassive black hole that contains at least a billion times as much matter as our Sun.

“It is surprising that such a giant galaxy existed when the Universe was only one-sixteenth of its present age,” said Dr. Tomotsugu Goto, “and that it hosted a black hole one billion times more massive than the Sun. The galaxy and black hole must have formed very rapidly in the early Universe.”

Knowledge of the host galaxies of supermassive black holes is important in order to understand the long-standing mystery of how galaxies and black holes have evolved together. Until now, studying host galaxies in the distant Universe has been extremely difficult because the blinding bright light from the vicinity of the black hole makes it more difficult to see the already faint light from the host galaxy.

The upper, middle, lower panels are for i0, z0 and zr-band, respectively.In each line, the left panels are reduced images. The middle panels are PSFs constructed using nearby stars. The right panels show residuals from the PSF subtraction. All figures are north up, east left.

To see the supermassive black hole, the team of scientists used new red-sensitive Charge Coupled Devices (CCDs) installed in the Suprime-Cam camera on the Subaru telescope on Mauna Kea. Prof. Satoshi Miyazaki of the National Astronomical Observatory of Japan (NAOJ) is a lead investigator for the creation of the new CCDs and a collaborator on this project. He said, “The improved sensitivity of the new CCDs has brought an exciting discovery as its very first result.”

The origin of the supermassive black holes remains an unsolved problem, and this new device and its findings could open a new window for investigating galaxy-black hole co-evolution at the dawn of the Universe.

A currently favored model requires several intermediate black holes to merge. The host galaxy discovered in this work provides a reservoir of such intermediate black holes. After forming, supermassive black holes often continue to grow because their gravity draws in matter from surrounding objects. The energy released in this process accounts for the bright light emitted from the region around the black holes.

A careful analysis of the data revealed that 40 percent of the near-infrared light observed (at the wavelength of 9100 Angstroms) is from the host galaxy itself and 60 percent is from the surrounding clouds of material (nebulae) illuminated by the black hole.

The scientists results will be published in the journal Monthly Notices of the Royal Astronomical Society later in September. Their paper is available here.

Source: RAS

September 1, 2009December 24, 2015 by Nancy Atkinson

New Way to Measure Curvature of Space Could Unite Gravity Theory

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Einstein’s general theory of relativity describes gravity in terms of the geometry of both space and time. Far from a source of gravity, such as a star like our sun, space is “flat” and clocks tick at their normal rate. Closer to a source of gravity, however, clocks slow down and space is curved. But measuring this curvature of space is difficult. However, scientists have now used a continent-wide array of radio telescopes to make an extremely precise measurement of the curvature of space caused by the Sun’s gravity. This new technique promises to contribute greatly in studying quantum physics.

“Measuring the curvature of space caused by gravity is one of the most sensitive ways to learn how Einstein’s theory of General Relativity relates to quantum physics. Uniting gravity theory with quantum theory is a major goal of 21st-Century physics, and these astronomical measurements are a key to understanding the relationship between the two,” said Sergei Kopeikin of the University of Missouri.

Kopeikin and his colleagues used the National Science Foundation’s Very Long Baseline Array (VLBA) radio-telescope system to measure the bending of light caused by the Sun’s gravity to within one part in ~~30,000~~ 3,333 (corrected by NRAO and updated here on 9/03/09 — see this link provided by Ned Wright of UCLA for more information on deflection and delay of light). With further observations, the scientists say their precision technique can make the most accurate measure ever of this phenomenon.

Bending of starlight by gravity was predicted by Albert Einstein when he published his theory of General Relativity in 1916. According to relativity theory, the strong gravity of a massive object such as the Sun produces curvature in the nearby space, which alters the path of light or radio waves passing near the object. The phenomenon was first observed during a solar eclipse in 1919.

Though numerous measurements of the effect have been made over the intervening 90 years, the problem of merging General Relativity and quantum theory has required ever more accurate observations. Physicists describe the space curvature and gravitational light-bending as a parameter called “gamma.” Einstein’s theory holds that gamma should equal exactly 1.0.

“Even a value that differs by one part in a million from 1.0 would have major ramifications for the goal of uniting gravity theory and quantum theory, and thus in predicting the phenomena in high-gravity regions near black holes,” Kopeikin said.

To make extremely precise measurements, the scientists turned to the VLBA, a continent-wide system of radio telescopes ranging from Hawaii to the Virgin Islands. The VLBA offers the power to make the most accurate position measurements in the sky and the most detailed images of any astronomical instrument available.

Sun's Path in Sky in Front of Quasars, 2005. Credit: NRAO

The researchers made their observations as the Sun passed nearly in front of four distant quasars — faraway galaxies with supermassive black holes at their cores — in October of 2005. The Sun’s gravity caused slight changes in the apparent positions of the quasars because it deflected the radio waves coming from the more-distant objects.

The result was a measured value of gamma of 0.9998 +/- 0.0003, in excellent agreement with Einstein’s prediction of 1.0.

“With more observations like ours, in addition to complementary measurements such as those made with NASA’s Cassini spacecraft, we can improve the accuracy of this measurement by at least a factor of four, to provide the best measurement ever of gamma,” said Edward Fomalont of the National Radio Astronomy Observatory (NRAO). “Since gamma is a fundamental parameter of gravitational theories, its measurement using different observational methods is crucial to obtain a value that is supported by the physics community,” Fomalont added.

Kopeikin and Fomalont worked with John Benson of the NRAO and Gabor Lanyi of NASA’s Jet Propulsion Laboratory. They reported their findings in the July 10 issue of the Astrophysical Journal.

Source: NRAO

September 1, 2009April 26, 2016 by Nancy Atkinson

Satellite Images of California Wildfires, Mt. Wilson Update

NASA's Aqua Satellite MODIS Instrument view of the California wildfires. Credit: NAS

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The wildfires near Los Angeles have spread to over 100,000 acres. The Los Angeles Times reported that the fire had burned 74 structures and remained out of control, spreading both west and north. As of 6:30 p.m. Pacific Daylight Time on August 31, some 12,000 homes were threatened. Fire fighters struggled to save the Mt. Wilson Observatory from the encroaching fire. Today, fire fighters set controlled backfires in effort to remove the closest vegetation to the various telescope structures. See below for a labeled image of the structures on Mt. Wilson amid smoke from the fires, courtesy of Emily Lakdawalla of the Planetary Society, along with more satellite, ground and helicopter images from the fires.

Mt. Wilson with labeled names of scopes. Courtesy of Emily Lakdawalla

Imagery from Mt. Wilson’s tower camera, recently went offline, likely due to loss of power. They have a back up site, available here, and staff from the observatory are still posting updates. While it was alarming to see the observatory structures surround and sometimes not visible because of smoke, the Mt. Wilson staff assured that they structures were still safe, and the fires were planned:

The [fire fighter’s] plan, which they would have implemented earlier had they not been withdrawn, was to start these groundlevel fire and literally walk along with them to keep them controlled. This is why we see no flames. The fires will consume the accumulation of needles from the many pine and fir trees as well as other scrub growth that could flame up and ignite lower limbs that would them permit the blossoming of the entire tree into flames. All the smoke we see is entirely consistent with this procedure. Larry and Dave are both delighted to see what’s going on, but I’ve got to say that seeing smoke next to those domes is very unsettling to me. Still, I know what the fire fighters are now doing is necessary to save the Observatory.

The latest news is that 4 acres of water is going to be dropped on the north side of Mt.W towers on Tuesday afternoon in an effort to save the observatory and communications towers.

A live view from a helicopter from station KTLA is available here. UPDATE: That feed is cutting out frequently due to demand. Try this one instead. (It is from a Fox station from anyone who thinks I have something against Fox….)

View this link to see a map of where the fire has spread. It is a Google map that is updated frequently.

The Los Angeles times blog reports that the “Station” fire, as it is called, in Angeles National Forest has been creeping east, toward the center of the San Gabriel Mountains. But its growth has been slower in the last 24 hours than it was over the weekend, thanks to higher humidity.

The fire’s maximum borders are roughly 25 miles from west to east and 18 miles north to south, covering the entire length of Angeles National Forest.

This image from NASA’s GOES-O satellite shows how far the smoke from the fires has spread.

GOES O image of smoke from the California fires, reaching nearly across Nevada. Credit: NASA

Image from NASA's Terra Satellite, taken August 30, 2009. Credit: NASA

This image was acquired mid-morning on Aug. 30 by the backward (northward)-viewing camera of the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA’s Terra satellite. The image is shown in an approximate perspective view at an angle of 46 degrees off of vertical. The area covered by the image is 245 kilometers (152 miles) wide. Several pyrocumulus clouds, created by the Station Fire, are visible above the smoke plumes rising from the San Gabriel Mountains north of Los Angeles in the left-center of the image. Smoke from the Station fire is seen covering the interior valleys along the south side of the San Gabriel Mountains, along with parts of the City of Los Angeles and Orange County, and can be seen drifting for hundreds of kilometers to the east over the Mojave Desert.

This striking time-lapse video of the fires at sunset, taken on August 29 from Mulhulland Drive in Los Angeles, show the fires spreading.

Sources: Mt. Wilson observatory website fire update, Los Angeles Times, New York Times, NASA Earth Observatory

September 1, 2009December 24, 2015 by Nancy Atkinson

Watch Saturn’s Rings Disappear (Video)

Composite image of Saturn over 6 years. Credit: Alan Friedman

On September 4, 2009, Earth’s orbital motion will carry it through the same plane as Saturn’s rings. From our vantage point, the rings will disappear. Usually these ring plane crossings — which only happen about every 15 years — are great opportunities to observe Saturn’s moons. But this year’s ring plane crossing will be practically impossible to see, as Saturn will be very close to the sun, only 11 degrees away. So, disappointingly, we won’t see much. However, amateur astronomer Alan Friedman has given us a glimpse of what this event will look like, without the glare from the sun. Friedman has put together an animation of how the angle of Saturn’s rings have changed over the past six years. See the animation below. “It shows the changing plane of the ring system as viewed from my Buffalo backyard from 2004 to 2009,” said Friedman. “The final frame has been assembled from earlier 2009 observations to display how the planet will appear with its rings edge on.” Gorgeous!

6 years of Saturn observations were combined to create this animation showing the changing plane of the ring system as viewed from earth. Credit: Alan Friedman

But, Friedman says, our real view of Saturn should get much better and provide a real treat this autumn. “In the fall of 2009, Saturn will emerge from the glare of the sun in the early morning sky and provide Earth-bound astronomers with our first glimpse of its blue north pole in 14 years,” he said.

Enjoy perusing Friedman’s impressive gallery on his website.

And thanks, Alan, for sharing your six-year endeavor with Universe Today!

September 1, 2009December 24, 2015 by Nancy Atkinson

After Loss of Lunar Orbiter, India Looks to Mars Mission

India Moon Mission — Artist concept of Chandrayaan-1 orbiting the moon. Credit: ISRO

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After giving up on re-establishing contact with the Chandrayaan-1 lunar orbiter, Indian Space Research Organization (ISRO) Chairman G. Madhavan Nair announced the space agency hopes to launch its first mission to Mars sometime between 2013 and 2015. Nair said the termination of Chandrayaan-1, although sad, is not a setback and India will move ahead with its plans for the Chandrayaan-2 mission to land an unmanned rover on the moon’s surface to prospect for chemicals, and in four to six years launch a robotic mission to Mars.

“We have given a call for proposal to different scientific communities,” Nair told reporters. “Depending on the type of experiments they propose, we will be able to plan the mission. The mission is at conceptual stage and will be taken up after Chandrayaan-2.”

On the decision to quickly pull the plug on Chandrayaan-1, Nair said, “There was no possibility of retrieving it. (But) it was a great success. We could collect a large volume of data, including more than 70,000 images of the moon. In that sense, 95 percent of the objective was completed.”

Contact with Chandrayaan-1 may have been lost because its antenna rotated out of direct contact with Earth, ISRO officials said. Earlier this year, the spacecraft lost both its primary and back-up star sensors, which use the positions of stars to orient the spacecraft.

The loss of Chandrayaan-1 comes less than a week after the spacecraft’s orbit was adjusted to team up with NASA’s Lunar Reconnaissance Orbiter for a Bi-static radar experiment. During the maneuver, Chandrayaan-1 fired its radar beam into Erlanger Crater on the moon’s north pole. Both spacecraft listened for echoes that might indicate the presence of water ice – a precious resource for future lunar explorers. The results of that experiment have not yet been released.

Chandrayaan-1 craft was designed to orbit the moon for two years, but lasted 315 days. It will take about 1,000 days until it crashes to the lunar surface and is being tracked by the U.S. and Russia, ISRO said.

The Chandrayaan I had 11 payloads, including a terrain-mapping camera designed to create a three-dimensional atlas of the moon. It is also carrying mapping instruments for the European Space Agency, radiation-measuring equipment for the Bulgarian Academy of Sciences and two devices for NASA, including the radar instrument to assess mineral composition and look for ice deposits. India launched its first rocket in 1963 and first satellite in 1975. The country’s satellite program is one of the largest communication systems in the world.

Sources: New Scientist, Xinhuanet

August 31, 2009December 24, 2015 by Brian Ventrudo

Is The Milky Way Doomed By Galactic Bombardment?

This image from a supercomputer simulation shows the density of dark matter in our Milky Way galaxy which is known to contain an ancient thin disk of stars. Brightness (blue-to-violet-to-red-to-yellow) corresponds to increasing concentration of dark matter.

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As scientists attempt to learn more about how galaxies evolve, an open question has been whether collisions with our dwarf galactic neighbors will one day tear apart the disk of the Milky Way.

That grisly fate is unlikely, a new study now suggests.

While astronomers know that such collisions have probably occurred in the past, the new computer simulations show that instead of destroying a galaxy, these collisions “puff up” a galactic disk, particularly around the edges, and produce structures called stellar rings.

The finding solves two mysteries: the likely fate of the Milky Way at the hands of its satellite galaxies — the most massive of which are the Large and Small Magellanic Clouds — and the origin of its puffy edges, which astronomers have seen elsewhere in the universe and dubbed “flares.”

The mysterious dark matter that makes up most of the universe plays a role, the study found.

Astronomers believe that all galaxies are embedded within massive and extended halos of dark matter, and that most large galaxies lie at the intersections of filaments of dark matter, which form a kind of gigantic web in our universe. Smaller satellite galaxies flow along strands of the web, and get pulled into orbit around large galaxies such as our Milky Way.

Ohio State University astronomer Stelios Kazantzidis and his colleagues performed detailed computer simulations of galaxy formation to determine what would happen if a satellite galaxy — such as the Large Magellanic Cloud and its associated dark matter — collided with a spiral galaxy such as our own.

The researchers considered the impacts of many different smaller galaxies onto a larger, primary disk galaxy. They calculated the likely number of satellites and the orbital paths of those satellites, and then simulated what would happen during collision, including when the dark matter interacted gravitationally with the disk of the spiral galaxy.

The conclusion? None of the disk galaxies were torn apart. To the contrary, the primary galaxies gradually disintegrated the in-falling satellites, whose material ultimately became part of the larger galaxy. The satellites passed through the galactic disk over and over, and on each pass, they would lose some of their mass, a process that would eventually destroy them completely.

Though the primary galaxy survived, it did form flared edges which closely resembled our galaxy’s flared appearance today.

Does that settle the question of the fate of the Milky Way?

Kazantzidis couldn’t offer a 100-percent guarantee.

“We can’t know for sure what’s going to happen to the Milky Way, but we can say that our findings apply to a broad class of galaxies similar to our own,” Kazantzidis said. “Our simulations showed that the satellite galaxy impacts don’t destroy spiral galaxies — they actually drive their evolution, by producing this flared shape and creating stellar rings — spectacular rings of stars that we’ve seen in many spiral galaxies in the universe.”

Source: Ohio State University

August 31, 2009April 17, 2017 by John Carl Villanueva

What are Divergent Boundaries?

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

August 31, 2009December 24, 2015 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