Universe Today

February 7, 2008December 26, 2015 by Ian O'Neill

The “Astronomical Unit” May Need an Upgrade as the Sun Loses Mass

The Sun is constantly losing mass. Our closest star is shedding material through the solar wind, coronal mass ejections and by simply generating light. As the burning giant begins a new solar cycle, it continues to lose about 6 billion kilograms (that’s approximately 16 Empire State Building’s worth) of mass per second. This may seem like a lot, but when compared with the total mass of the Sun (of nearly 2Ã—10³⁰ kilograms), this rate of mass loss is miniscule. However small the mass loss, the mass of the Sun is not constant. So, when using the Astronomical Unit (AU), problems will begin to surface in astronomical calculations as this “universal constant” is based on the mass of the Sun…

The AU is commonly used to describe distances within the Solar System. For instance, one AU is approximately the mean distance from the Sun to Earth orbit (defined as 149,597,870.691 kilometres). Mars has an average orbit of 1.5AU, Mercury has an average of about 0.4AU… But how is the distance of one AU defined? Most commonly thought to be derived as the mean distance of the Sun-Earth orbit, it is actually officially defined as: the radius of an unperturbed circular orbit that a massless body would revolve about the Sun in 2Ï€/k days (that’s one year). ThereÂ lies theÂ problem. The official calculation is based on “k”, a constant based on the estimated constant mass of the Sun.Â But theÂ mass of the Sun ain’t constant.

As mass is lost via the solar wind and radiation (radiation energy will carry mass from the Sun due to the energy-mass relationship defined by Einstein’s E=mc²), the value of the Astronomical Unit will increase, and by its definition, the orbit of the planets should also increase. It has been calculated that Mercury will lag behind it’s current orbital position in 200 years time by 5.5 km if we continue to use today’s AU in future calculations. Although a tiny number – astrophysicists are unlikely to lose any sleep over the discrepancy – a universal constant should be just that, constant. There are now calls to correct for this gradual increase in the value of the AU by discarding it all together.

“[The current definition is] fine for first-year science courses. But for scientific and engineering usage, it is essential to get it right.” – Peter Noerdlinger, astronomer at St Mary’s University, Canada.

Correcting classical “constants” in physics is essential when high accuracy is required to calculate quantities over massive distances or long periods of time, therefore the AU (as it is currently defined) may be demoted as a general description of distance rather than a standard scientific unit.

Source: New Scientist

February 7, 2008December 26, 2015 by Fraser Cain

Name That Satellite

Have you ever named a space mission? Well, here’s your chance. NASA announced today that they’re looking for help from the public to rename their upcoming Gamma-ray Large Area Space Telescope (GLAST) before it launches in mid-2008.

Think you’ve got a good idea for a name? Here’s what the mission’s going to be doing:

– Explore the most extreme environments in the universe, where nature harnesses energies far beyond anything possible on Earth
– Search for signs of new laws of physics and what composes the mysterious dark matter
– Explain how black holes accelerate immense jets of material to nearly light speed
– Help crack the mysteries of the stupendously powerful explosions known as gamma-ray bursts
– Answer long-standing questions about a broad range of phenomena, including solar flares, pulsars and the origin of cosmic rays

So, come up with a name that’s very high-energy. Send in the name along with a statement of 25 words on why you like your idea to NASA’s “Name That Satellite”.

Click here to access the website.

You’ve got until March 31, 2008, so get thinking.

Original Source: NASA News Release

February 7, 2008December 26, 2015 by Fraser Cain

Astrosphere for February 7, 2008

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Your photograph for today is the recent conjunction between Jupiter and Venus, captured by Shevill Mathers.

Starts with a Bang looks at the Cosmic Microwave Background Radiation’s inevitable slide towards the Radio Background.

A day without Astronomy Picture of the Day isn’t a day. Today, check out NGC 4013.

Pamela Gay reviews astronomy software called “Where is M13”.

There was a solar eclipse, did you notice? Ian Musgrave had the right perspective, and caught just a tiny snip taken out of the Sun.

Wired has a list of 10 technologies we could build if they weren’t so friggin expensive.

Now this is thinking big. Next Big Future has an article about a rail gun system that could launch spacecraft into orbit.

Centauri Dreams looks at Project Longshot. A mission to send a probe to another star.

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 7, 2008December 29, 2015 by Fraser Cain

Carnival of Space #40

This week, the Carnival of Space moves to another new home: Orbiting Frog. Check out the cool thumbnail view that lets you browse through all the entries, or a traditional HTML view. Very clever.

Click here to read the Carnival of Space #40

And if you’re interested in looking back, here’s an archive to all the past carnivals of space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let me know if you can be a host, and I’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

February 7, 2008December 26, 2015 by Nancy Atkinson

Another Asteroid Passes Close to Earth

On Tuesday, February 5, 2008 an SUV sized asteroid passed between the Earth and the moon. Asteroid 2008 CT1 came within 135,000 kilometers ( 84,000 miles) of Earth, only a third of the distance to the moon. The asteroid was discovered only two days before its close approach to Earth, spotted by the Lincoln Near Earth Asteroid Research (LINEAR) project, using robotic telescopes located at New Mexico’s White Sands Missile Range. The asteroid’s size is estimated between 8 – 15 meters.

While this asteroid seems small, we know that even small rocks can be devastating. Last September, a meteorite estimated at .2 – 2 meters wide created a crater 13 meters wide in Peru. The cause of the Tunguska Event of the early 20th Century is now believed to be a 35m rock that never even touched the ground. It’s believed that it exploded a few miles above the ground, creating a shockwave that devastated the landscape below.

2008 CT1 could possibly return to Earthâ€™s vicinity in 2041, although its orbit has not yet been well defined, so that prediction could change. It is also a possible Mercury impactor, since that that planet is very near the asteroidâ€™s currently calculated perihelion.

LINEAR uses a Ground-based Electro-Optical Deep Space Surveillance (GEODSS) telescope, and has detected over 3,000,000 asteroids since 1998, which is about 70% of the known near-Earth asteroids.

Original News Source: SLOOH Skylog

February 7, 2008December 26, 2015 by Ian O'Neill

Large Hadron Collider Could Create Wormholes: a Gateway for Time Travelers?

As we get closer to the grand opening of the Large Hadron Collider (LHC) near Geneva, Switzerland, it seems the predictions as to what we might get from the high energy particle accelerator are becoming more complex and outlandish. Not only could the LHC generate enough energy to create particles that exist in other dimensions, it may also produce “unparticles“, a possible source for dark matter. Now, the energy may be so focused that even the fabric of space-time may be pulled apart to create a wormhole, not to a different place, but a different time. Also, if there are any time travellers out there, we are most likely to see them in a few weeks…

If you could travel back in time, where would you go? Actually it’s a trick question: you couldn’t travel back in time unless there was a time “machine” already built in the past. The universe’s very first time traveller would therefore only be able to travel back to when the machine he/she was using was built. This is one restriction that puts pay to those romantic ideas that we could travel back in time to see the dinosaurs; there were no time machines back then (that we know of), so nothing to travel back to. And until we create a time machine, we won’t be seeing any travelers any time soon.

However, Prof Irina Aref’eva and Dr Igor Volovich, mathematical physicists at the Steklov Mathematical Institute in Moscow believe the energies generated by the subatomic collisions in the LHC may be powerful enough to rip space-time itself, spawning wormholes. A wormhole not only has the ability to take a shortcut between two positions in space, it can also take a shortcut between two positions in time. So, the LHC could be the first ever “time machine”, providing future time travelers with a documented time and place where a wormhole “opened up” into our time-line. This year could therefore be “Year Zero”, the base year by which time travel is limited to.

Relativity doesn’t dispute this idea, but the likelihood of a person passing through time is slim-to-impossible when the dimensions of a possible wormhole will be at the sub-atomic level at best and it would only be open for a brief moment. Testing for the presence of a man-made wormhole would be difficult even if we knew what we were looking for (perhaps a small loss in energy during collision, as energy escapes through the wormhole?).

As if that didn’t discourage you from hoping to use wormholes for time travel, Dr Brian Cox of the University of Manchester says: “The energies of billions of cosmic rays that have been hitting the Earth’s atmosphere for five billion years far exceed those we will create at the LHC, so by this logic time travellers should be here already.” As far as we know, they’re not.

Source: Telegraph.co.uk

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

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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.