Universe Today

February 7, 2008April 26, 2016 by Ian O'Neill

Building a Moon Base: Part 1 – Challenges and Hazards

So, we want to go to the Moon. Why? Because the Moon is an ideal “staging post” for us to accumulate materials and manpower outside of the Earth’s deep gravitational well. From the Moon we can send missions into deep space and ferry colonists to Mars. Tourists may also be interested in a short visit. Mining companies will no doubt want to set up camp there. The pursuit of science is also a major draw. For what ever reason, to maintain a presence on this small dusty satellite, we will need to build a Moon base. Be it for the short-term or long-term, man will need to colonize the Moon. But where would we live? How could we survive on this hostile landscape? This is where structural engineers will step in, to design, and build, the most extreme habitats ever conceived…

Manned missions to Mars take up a lot of the limelight insofar as colonization efforts are concerned, so it’s about time some focus is aimed at the ongoing and established concepts for colonization of the Moon. We currently have a means of getting there (after all, it is nearly 40 years ago since Apollo 11) and our technology is sufficiently advanced to sustain life in space, the next step is to begin building… In this first installment of “Building a Moon Base”, we look at the immediate issues facing engineers when planning habitats on a lunar landscape.

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases”)

The debate still rages as to whether man should settle on the Moon or Mars first. Mars is often considered to be the ultimate challenge for mankind: to live on a planet other than Earth. But looking down on us during cloudless nights is the bright and attainable Moon. From here we can see the details of the lunar landscape with the naked eye, it is so close astronomically when compared with the planets, that many believe that the Moon should be our first port of call before we begin the six month (at best) voyage to the Red Planet. It also helps as we’ve already been there…

Opinion has shifted somewhat in recent years from the “Mars Direct” plan (in the mid-1990s) to the “Moon First” idea, and this shift has recently been highlighted by US President George W. Bush when in 2004 he set out plans for re-establishing a presence on the Moon before we can begin planning for Mars. It makes sense; many human physiological issues remain to be identified, plus the technology for colonization can only be tested to its full extent when… well… colonizing.

Understanding how the human body will adapt to life in low-G and how new technologies will perform in a location close enough to home will be not only be assuring to lunar colonists and astronauts, it will also be sensible. Exploring space is dangerous enough, minimizing the risk of mission failure will be critical to the future of manned exploration of the Solar System.

So where do you start when designing a moon base? High up on the structural engineers “to do” list would be the damage building materials may face when exposed to a vacuum. Damage from severe temperature variations, high velocity micrometeorite impacts, high outward forces from pressurized habitats, material brittleness at very low temperatures and cumulative abrasion by high energy cosmic rays and solar wind particles will all factor highly in the planning phase. Once all the hazards are outlined, work can begin on the structures themselves.

The Moon exerts a gravitational pull 1/6th that of the Earth, so engineers will be allowed to build less gravity-restricted structures. Also, local materials should be used where and when possible. The launch costs from Earth for building supplies would be astronomical, so building materials should be mined rather than imported. Lunar regolith (fine grains of pulverized Moon rock) for example can be used to cover parts of habitats to protect settlers from cancer-causing cosmic rays and provide insulation. According to studies, a regolith thickness of least 2.5 meters is required to protect the human body to a “safe” background level of radiation. High energy efficiency will also be required, so the designs must incorporate highly insulating materials to insure minimum loss of heat. Additional protection from meteorite impacts must be considered as the Moon has a near-zero atmosphere necessary to burn up incoming space debris. Perhaps underground dwellings would be a good idea?

The actual construction of a base will be very difficult in itself. Obviously, the low-G environment poses some difficulty to construction workers to get around, but the lack of an atmosphere would prove very damaging. Without the buffering of air around drilling tools, dynamic friction will be amplified during drilling tasks, generating huge amounts of heat. Drill bits and rock will fuse, hindering progress. Should demolition tasks need to be carried out, explosions in a vacuum would create countless high velocity missiles tearing through anything in their path, with no atmosphere to slow them down. (You wouldn’t want to be eating dinner in an inflatable habitat during mining activities should a rock fragment be flying your way…) Also, the ejected dust would obscure everything and settle, statically, on machinery and contaminate everything. Decontamination via air locks will not be efficient enough to remove all the dust from spacesuits, Moon dust would be ingested and breathed in – a health risk we will not fully comprehend until we are there.

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

Could Nitrogen Pollution Give Tropical Flora a Much Needed Boost?

Global warming and subsequent climate change is directly linked with human activity on our planet. The greenhouse effect is amplified by our need for energy, burning fossil fuels and pumping vast quantities of CO₂ into our atmosphere. To make things worse, the plants that form the Earth’s “lungs” in the tropics are being destroyed on a massive scale, so less carbon dioxide can be scrubbed from the air. However, it’s not all bad news. Industry and agriculture also generate large amounts of excess nitrogen pollution and scientists now believe that this nitrogen (a main ingredient for fertilizer) may help to increase tropical plant growth by up to 20%…

From our high school classes, we all know that green plants, through photosynthesis, absorb atmospheric carbon dioxide. It is essential for plants to flourish. By far the largest absorbers of carbon dioxide are the tropical rainforests in the Amazon basin, central Africa and southern Asia. They are often referred to as the “lungs” of Earth, as they absorb much of the atmospheric CO₂ and provide balance to the carbon budget of our climate. If this resource is removed through wholesale deforestation, more CO₂ collects in the atmosphere and global warming is amplified by the increase of this greenhouse gas.

However, help may be at hand. Taking the results from over 100 previously published studies, David LeBauer and Kathleen Treseder from the University of California Irvine, believe they have found a trend that suggests a strong link between nitrogen pollution and increased plant growth in tropical regions. Increased plant growth is a welcomed consequence of human activity, as faster plant growth means more plants to absorb more CO₂. Although deforestation is a global catastrophe (much of the ancient forests will never recover and a vast proportion of plant and animal species are now extinct), the new research published in Ecology may influence future climate change models.

“We hope our results will improve global change forecasts.” – David LeBauer, UCI graduate student researcher of Earth system science and lead author of the study.

Nitrogen pollution comes in many forms, the most obvious being from agricultural activity (fertilizer) polluting water supplies and industrial burning emitting nitrogen into the air. What’s more, nitrogen pollution is on the increase, especially in developing countries.

Nitrogen pollution has often been ignored as a possible growth agent in the tropics, as other fertilizing elements are in short supply (typically, if one element is low, no matter how high the other element is, it will have little or no effect on plant growth). Phosphorus for example, is low in tropical regions, but according to the new research, this doesn’t seem to factor and plant growth is increased by 20% regardless.

LeBauer adds: “What is clear is that we need to consider how nitrogen pollution interacts with carbon dioxide pollution. Our study is a step toward understanding the far-reaching effects of nitrogen pollution and how it may change our climate…” It may only be a step, but at least it’s a positive one.

Source: Physorg.com

February 6, 2008December 26, 2015 by Fraser Cain

Researchers Explain Enceladus’ Icy Plume

Yesterday I blogged about how particles jetting from Enceladus find their way to Saturn’s A-Ring. Now there’s a new report that models how ice and vapour come pouring out of cracks on Enceladus’ surface in the first place.

Since Cassini first discovered jets of water ice blasting out of Saturn’s moon Enceladus, scientists have been trying to explain the process that could make this happen. The moon is very very cold; too far away to be warmed by the Sun.

Scientists now know that the jets are emanating from a series of cracks near Enceladus’ southern pole; these cracks have been dubbed “tiger stripes”. A team of German researchers, led by Juergen Schmidt of the University of Potsdam, have developed a computer model that describes what the bottom of those tiger stripes might look like.

According to Schmidt, they have to be at a temperature of 0 degrees Celsius. This is the triple point of water, where vapour, ice and liquid can all exist at the same time.

Water vapour and ice grains are blasted through funnels in the tiger stripes. The heavier grains rub against the sides of the holes and slow down.

This helps explain why ice particles coming out of Enceladus move at a slower velocity than the water vapour.

The process of tidal heating is probably keeping the interior of Enceladus warm. As it orbits around Saturn, the powerful gravitational force causes the tiny moon to flex back and forth. This creates heat within it. A more dramatic version of this process can be seen with Jupiter’s moon Io, which is heated to the point that volcanoes erupt across its surface.

The surface of Enceladus is -193 degrees Celsius, while the tiger stripes are -133 C. This means that the interior of the moon must be even warmer.

The researchers have published their work in this week’s issue of the journal Nature.

Original Source: Nature

February 6, 2008April 26, 2016 by Fraser Cain

Review: Infinity 125 mW Green Laser

green-laser-pointer-infiniti-series-working-status.thumbnail.jpg

Have you ever tried to point out the constellations to a friend? You huddle up close, point your arm out, and both of you try to locate the star you’re looking at. “See that star? Right there? Now down a little, no, not that one. It’s on the left… never mind, there’s the Moon over there.” I had a chance to play with a green laser pointer from techlasers.com, and let me tell you, that problem goes away once and for all.

The laser I received is the Infinity 125 mW laser from techlasers and it retails for $289.00 USD. But they also have lower watt lasers right down to 15 mW (for $79.00).

All their Infinity series are the size of a large pen. You can easily clip this in your shirt pocket, and whip it out when you need to clear up a constellation conundrum.

As long as you’re using the laser for good, it’s awesome. You point up into the sky, press the trigger, and a finger of light stretches from your hand to infinity. Instead of standing beside someone, with your arm outstretched, trying to point out a specific, dim object in the sky, you can just reach out and point to it.

I’m not kidding. Zap, your laser reaches out to a specific star. There’s Venus, that’s Mars. Zap… that’s Andromeda.

It only takes 2 AAA batteries, and I’ve been using it for the better part of a month now, amazing my friends and entertaining my children, and it hasn’t run out of batteries yet.

I’ve tested it around the house, and the spot where the laser hits the wall is almost too bright to look at. You can easily see the spot on a building a few miles away, and I’m sure distant aliens are squinting their eyes from the light when you beam it at their star (okay, not really). I’m sure my neighbours are wondering what that green beam is stretching up from my house.

I’ve got to say, though, it feels a bit like owning a firearm. I keep the laser out of reach of the kids, and make sure that we only use it with my supervision. I can imagine it would seriously damage someone’s eyes if you weren’t careful.

But if you’re a responsible person, and you keep it away from airplanes flying overhead, I would say that a green laser is a great way to share your love of astronomy with your friends.

Check out Pamela’s review over at StarStryder, where she breaks out the math to calculate how powerful the laser is.

And then take a look at techlasers for their full gallery of lasers.

February 6, 2008December 26, 2015 by Fraser Cain

Dark Matter and Dark Energy… the Same Thing?

I’ve said it many times, but it bears repeating: regular matter only accounts for 4% of the Universe. The other 96% – dark matter and dark energy – is a total mystery. Wouldn’t it be convenient if we could find a single explanation for both? Astronomers from the University of St. Andrews are ready to decrease the mysteries down to one.

Dr. HongSheng Zhao at the University of St. Andrews School of Physics and Astronomy has developed a model that shows how dark energy and dark matter are more closely linked than previously thought.

Dr Zhao points out, “Both dark matter and dark energy could be two faces of the same coin. “As astronomers gain understanding of the subtle effects of dark energy in galaxies in the future, we will solve the mystery of astronomical dark matter at the same time.”

Just a quick explainer. Dark energy was discovered in the late 1990s during a survey of distant supernova. Instead of finding evidence that the mutual gravity of all the objects in the Universe is slowing down its expansion, researchers discovered that its expansion is actually accellerating.

Dark matter was first theorized back in 1933 by Swiss astronomer Fritz Zwicky. He noted that galaxies shouldn’t be able to hold themselves together with just the regular matter we can see. There must be some additional, invisible matter surrounding the regular matter that provides the additional gravitational force to hold everything together.

And since their discoveries plenty of additional evidence for both dark energy and dark matter have been seen across the Universe.

In Dr. Zhao’s model, dark energy and dark matter the same thing that he calls a “dark fluid”. On the scale of galaxies, this fluid behaves like matter, providing a gravitational force. And in the large scales, the fluid helps drive the expansion of the Universe.

Dr. Zhao’s model is detailed enough to produce the same 3:1 ratio of dark energy to dark matter measured by cosmologists.

Of course, any theory like this only gains ground when it starts making predictions that can be tested through observation. Dr. Zhao expects the work at the Large Hadron Collider to be fruitless. If he’s right, dark matter particles will have such low energy that the collider won’t be able to generate them.

The paper was recently published in the Astrophysical Journal Letters in December 2007, and Physics Review D. 2007.

Original Source: University of St. Andrews News Release

February 6, 2008December 26, 2015 by Fraser Cain

Terrible Weather Will Probably Delay Atlantis Launch

People in the southeast United States are cleaning up from a powerful weather front that unleashed a series of devastating tornadoes across the landscape. At least 48 people are dead, and hundreds more are injured. And as you can probably guess, this weather could have an impact on tomorrow’s launch of the space shuttle Atlantis.

NASA’s shuttle launch weather officer, Kathy Winters said today that, “the storm prediction center is forecasting a five percent chance of severe weather in the central Florida area tomorrow. I think we could see isolated thunderstorms in the area.”

This is the same weather system that spawned all those tornadoes. In fact, tornado watches are still in effect in various parts of the southeast, including the western Florida panhandle; relatively nearby Cape Canaveral.

Not that tornadoes are expected to savage the launch facility. Still, managers are anticipating a 70% chance that heavy rains will prevent the shuttle from blasting off. Rain is a problem because it can damage the shuttle’s thermal protection system during its high-speed launch.

Although the weather is still a worry, there are no technical reasons remaining that could hold up Atlantis‘ launch. The issue with the malfunctioning fuel gauges has been resolved, and managers aren’t worried about a bent coolant hose that supplies Freon to keep the shuttle cool when it’s in space.

So, the expected launch date is still Thursday at 2:45 p.m. EST. And if that window closes, they’ll aim for a 2:19 p.m. EST launch on Friday.

Original Source: NASA Status Report

February 6, 2008April 26, 2016 by Fraser Cain

Astrosphere for February 6, 2008

Your image for the day is a montage of the Solar System (well, the Sun and 3 planets) captured by Rumples Riot in the forum. This is really cool. Does anyone have a more complete montage they’ve photographed?

Science journalist Will Gater has updated his website with a brand new blog and an RSS feed. His latest post, about the density of Mercury is pretty great too.

And while I’m mentioning new blogs, check out Starts With a Bang! by astrophysicist Ethan Seigel. I had a chance to meet Ethan at the American Astronomical Society meeting in Austin and he’s a great guy – and his blog is awesome. Here’s a sample post about the difference between centripetal and centrifugal force.

Becky spots a weather balloon floating over New Mexico. It’s easy to see how someone might think that’s a UFO.

APOD has a great photograph of the Sun. What is this Sun thing they’re talking about? We’ve still got clouds and more clouds here in Vancouver.

Keith Cowing at NASA Watch wonders who whines for Mars.

And finally, Astroprof looks at the Moon’s southern pole. A nice place to visit?

Do you have a space/astronomy blog? Let me know and I’ll subscribe to your news feed. Write something cool and I’ll link to it.

February 5, 2008April 26, 2016 by Fraser Cain

Stream of Hydrogen Connects the Milky Way and the Magellanic Clouds

If you live in the southern hemisphere, the Magellanic Clouds are a familiar sight. These are the closest, brightest examples of dwarf galaxies we can see from the Milky Way. Radio astronomers have discovered a tenuous stream of hydrogen connecting our galaxy together with the Magellanic Clouds. This stream will help astronomers calculate the motion of the Clouds. Have they been here for a long time, or are they just passing by.

The finger of hydrogen gas, called HVC306-2+230, is piercing through the disk of the Milky Way about 70,000 light-years away from our location. The exact point of contact is near the Southern Cross (you southerners know what I’m talking about).

Astronomers used to think that the Magellanic Clouds had orbited the Milky Way many times, slowly getting dismembered. But new observations from the Hubble Space Telescope showed that they’re actually moving much more quickly than previously believed. Instead of orbiting the Milky Way, they might just be passing us once, never to return.

By detecting where this leading arm strikes the Milky Way, astronomers will have an easier time calculating the Clouds’ trajectory.

“We think the Leading Arm is a tidal feature, gas pulled out of the Magellanic Clouds by the Milky Way’s gravity,” said Dr McClure-Griffiths, the research team leader from CSIRO’s Australia Telescope National Facility. “Where this gas goes, weâ€™d expect the Clouds to follow, at least approximately.”

Their discovery actually strengthens the original theory, that the Clouds have been orbiting the Milky Way for a long time. Of course, the researchers caution that this isn’t the final word on the subject – the flyby model still hasn’t been ruled out.

But if they’re right, the Magellanic Clouds will eventually merge with the Milky Way and not zoom past.

Original Source: CSIRO News Release

February 5, 2008April 26, 2016 by Fraser Cain

Astrosphere for February 5, 2008

Here’s a beautiful picture of star trails above Costa Rica captured by Tim S. Jones. Doesn’t it look like it’s raining stars?

Centauri Dreams searches for a double sunrise.

It’s boring work, but somebody’s got to do it. The Planetary Society Blog analyzes what’s good and bad in the new 2009 NASA budget. Alan Boyle calls it a comeback for big science. Yes, I’m putting off writing an article of my own. Can’t… stay… awake.

Remember Asteroid 2007 WD5? That was the one that might have hit Mars in late January, 2008. Maybe it hit, maybe it didn’t… I guess we’ll never know.

Wouldn’t it be convenient if dark matter and dark energy were the same thing? Then I could just call it dark manergy, or maybe dark eneratter.

CNN has joined the science/technology blog space with their new blog… SciTechBlog. Hey CNN, don’t forget to link over here once in a while.

Pamela reports on an interesting discovery about the multiple sources for gamma ray bursts.

Chris Lintott is back in Hawaii, trying to make his way up to the snowy summit to play with telescopes, but nature is denying entry.

Finally, the folks at Astronomy Magazine have reviewed Universe Today writer Tammy Plotner’s new book, the Night Sky Companion.

February 5, 2008December 26, 2015 by Fraser Cain

Enceladus is Supplying Ice to Saturn’s A-Ring

One of the biggest discoveries made by Cassini is at Saturn’s moon Enceladus, where great plumes of icy material were seen spewing from its southern pole. Now scientists think that this material is traveling all the way inward to get trapped into Saturn’s A-ring.

Scientists had already linked together Saturn’s E-ring with the material spewed out by Enceladus. And researchers had worked out that the whole magnetic environment around Saturn is weighed down by the Enceladus material, which becomes plasma.

But now this.

“Saturn’s A-ring and Enceladus are separated by 100,000 kilometers (62,000 miles), yet thereâ€™s a physical connection between the two,” says Dr. William Farrell of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Prior to Cassini, it was believed that the two bodies were separate and distinct entities, but Cassiniâ€™s unique observations indicate that Enceladus is actually delivering a portion of its mass directly to the outer edge of the A-ring.” Farrell is lead author of a paper on this Saturn discovery that appeared in Geophysical Research Letters January 23.

The gas particles are ejected from Enceladus and then become electrically charged by sunlight and through interactions with other particles. Once they’re charged, the particles can come under the sway of Saturn’s magnetic field, which traps and directs them around. The particles can move around from pole to pole, but once they enter Saturn’s A-ring, they’re stuck there for good.

Scientists had actually predicted this in the early 1990s. Using the Hubble Space Telescope, they saw a large presence of water-related molecules in orbit around Saturn. The researchers modeled the motions of this icy material, and calculated that it could migrate all the way in to the A-ring. But the source of this water cloud was unknown.

This discovery backs up the prediction, and provides a source for the cloud of water-related molecules feeding into the A-ring.

They’re coming from Enceladus.

Original Source: NASA News Release