Universe Today

July 24, 2008December 24, 2015 by Ian O'Neill

Project Lucifer: Will Cassini Turn Saturn into a Second Sun? (Part 1)

Project Lucifer. Could the plutonium fuel onboard the Cassini mission cause a nuclear chain reaction on Saturn? Credit: NASA/US Department of Defense

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The story: On October 15th 1997, the Cassini-Huygens mission blasted off from Cape Canaveral Air Force Station to explore Saturn and its moons. It continues to study the ringed gas giant today and its mission has been extended till 2010. Cassini is is powered by 32.8 kg (72 lbs) of plutonium fuel. A radioactive power source is the only option for missions travelling beyond the orbit of Mars as sunlight is too weak for solar panels to be effective. However, NASA (in association with secret organizations, such as the Illuminati or the Freemasons) wants to use this plutonium for a “higher purpose”, dropping Cassini deep into Saturn at the end of its mission where atmospheric pressures will be so large that it will compress the probe, detonating like a nuclear bomb. What’s more, this will trigger a chain reaction, kick-starting nuclear fusion, turning Saturn into a fireball. This is what has become known as The Lucifer Project. This second sun will have dire consequences for us on Earth, killing millions from the huge influx of radiation by this newborn star. Earth’s loss becomes the Saturn moon Titan’s gain, suddenly it is habitable and the organizations playing “God” can start a new civilization in the Saturn system. What’s more, exactly the same thing was attempted when the Galileo probe was dropped into Jupiter’s atmosphere in 2003…

The reality: Now that the Cassini mission has been extended by two years, we can expect this conspiracy theory to become more and more vocal in the coming months. But like the Galileo/Jupiter/second sun theory, this one is just as inaccurate, once again using bad science to scare people (much like Planet X then)…

So what happened when Galileo dropped into Jupiter?

Well… nothing really.

In 2003, NASA took the prudent decision to terminate the hugely successful Galileo mission by using its last drops of propellent to push it at high speed into the gas giant. By doing so, this ensured the probe would burn up during re-entry, dispersing and burning any contaminants (such as terrestrial bacteria and the radioactive plutonium-238 fuel on board). The primary concern about letting Galileo sit in a graveyard orbit was that if mission control lost contact (very likely as the radiation belts surrounding Jupiter were degrading the probe’s ageing electronics), there may have been the possibility that Galileo would crash into one of the Jovian moons, contaminating them and killing any possible extra-terrestrial microbial life. This was a serious concern, especially in the case of Europa which could be a prime location for life to thrive below its ice-encrusted surface.

Now this is where the intrigue begins. Long before Galileo plummeted into Jupiter’s atmosphere, conspiracy theorists cited that NASA wanted to create an explosion within the body of the gas giant, thus igniting a chain reaction, creating a second sun (Jupiter is often called a ‘failed star’, although it has always been way too small to support nuclear reactions in its core). This was proven wrong on many counts, but there were three main reasons why this could not happen:

The design of the radioisotope thermoelectric generators (RTGs) supplying energy to the craft wouldn’t allow it.
The physics behind a nuclear explosion (nuclear fission) wouldn’t allow it.
The physics of how a star works (nuclear fusion) wouldn’t allow it.

Five years after the Galileo impact, Jupiter still looks to be in fine health (and it certainly isn’t close to being a star). Although history has already proven you can’t create a star from a gas giant using a space probe (i.e. Jupiter + Probe ≠ Star), conspiracy theorists think that NASA’s evil plan failed and there is some evidence that something did happen after Galileo got swallowed by Jupiter (and that NASA is pinning their hopes on the Cassini/Saturn combo).

Cue the Big Black Spot

The mystery black spot in 2003 (by Eric Ng) compared with one of the Shoemaker-Levy 9 fragment impact sites in 1994 (NASA) — The mystery black spot in 2003 (by Eric Ng) compared with one of the Shoemaker-Levy 9 fragments impact sites in 1994 (NASA)

Backing up the conspiracy theorists’ claims that there was an explosion inside the Jovian atmosphere after Galileo hit was the discovery of a dark blob near the equator of Jupiter a month after the event. This was widely reported across the web, but only a couple of observations were made before it disappeared. Some explanations pointed out that the blob could have been a short-lived dynamic atmospheric feature or it was a shadow from one of the Jovian moons. After this initial excitement, nothing else surfaced about the phenomenon. However, some were keen to point out that the dark patch on Jupiter’s surface may have been a manifestation of a nuclear detonation from Galileo deep within the planet which, after a month, eventually floated to the surface. Comparisons had even made with the 1994 features generated by the impact of the pieces of Comet Shoemaker-Levy 9 (pictured above).

What ever the cause of this dark feature, it didn’t come from Galileo as a nuclear detonation simply was not possible. What’s more, a nuclear detonation from the Cassini mission when it enters Saturn’s atmosphere in 2010 is also impossible, and here’s why…

The Radioisotope Thermoelectric Generators (RTGs)

RTGs are a tried and tested technology in use since the 1960’s. Various RTG designs have been used on a huge number of missions including Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Galileo, Ulysses, Cassini and, most recently, New Horizons. RTGs are a very dependable source of power for space missions where solar panels have not been an option. For Cassini, if solar panels were used, they would need to have a huge area to collect the meagre sunlight at 10 AU, thus impractical to launch and operate.

The three RTGs on board Cassini are fuelled by small pellets of plutonium-238 (238Pu) encased separately in shock-proof containers known as general purpose heat source modules. There are 18 modules in each RTG. Through the use of thermocouples, the steady heat generated by the radioactive decay of the plutonium isotope is converted into electricity to supply Cassini. It is worth noting at this point that 238Pu is not weapon grade (i.e. it is very difficult to generate nuclear fission, 239Pu is more suited for this purpose). There are also dozens of Radioisotope Heater Units (RHUs) on board Cassini that provide a steady heat to critical subsystems, which contain single pellets of Pu-238. Again, these units are separated and shielded, each weighing 40 grams. For more details on this, check out the NASA Factsheet: Spacecraft Power for Cassini.

Inside an RHU and RTG (Roland Piquepaille)

Shielding is critical for each plutonium pellet, primarily to prevent radioactive contamination during launch of space missions. Should there be an incident during launch, space agencies such as NASA must assure the containment of the radioactive material. Therefore all RTGs and RHUs are completely safe regardless of the stresses they are put under.

So, like Galileo, Cassini will hit Saturn’s atmosphere at a high velocity (Galileo hit the Jovian atmosphere at a speed of 50 km/s) and disintegrate very quickly before burning to a cinder. The point I want to highlight here is that Cassini will break apart like any fast-moving object during re-entry.

Still, conspiracy theorists are quick to point out that Cassini is carrying a huge amount of plutonium, totalling 32.8 kg (even though it is not the weapon-grade 239Pu and all the bits of 238Pu are tiny pellets, encased in damage-proof containers, being scattered through Saturn’s atmosphere). But ignoring all the logical arguments against, it will still generate a nuclear explosion, right?

Alas, no.

So how does a nuclear bomb work anyway?

Artist impression of Galileo burning up when falling into the Jovian atmosphere. Credit: David A Hardy

For a general run-down of the basics behind a nuclear weapon, check out the very clear description at How Stuff Works: How Nuclear Bombs Work (scroll down to “Implosion-Triggered Fission Bomb,” as this is what the conspiracy theorists believe Cassini will emulate).

So there’s Cassini, plummeting through Saturn’s atmosphere in two years time. As it gets deeper, bits fall off and burnt by the friction caused by re-entry. When I say fall off, I mean they are no longer attached. For a nuclear detonation to occur we need a solid mass of weapon grade plutonium. By solid mass, I mean we need a minimum amount of the stuff for nuclear fission to occur (a.k.a. “critical mass”). The critical mass of 238Pu is approximately 10 kg (US DoE publication), so Cassini has enough 238Pu for three crude nuclear bombs (ignoring the fact that it is very difficult to build a 238Pu weapon in the first place). But how could all those tiny pellets of 238Pu be pulled together, in free-fall, casings removed, letting the pressure of Saturn’s atmosphere force it all together tipping it toward critical mass? Is that really possible? No.

An imploding nuclear weapon (answers.com)

Even if by some chance all the 238Pu in one RTG melded together, how would it detonate? For detonation of an implosion-triggered fission bomb to occur, sub-critical masses need to be forced together at the same instant. The only way this is possible is to surround the sub-critical masses with high-explosives so a shock wave rapidly collapses the sub-critical masses together. Only then may a chain reaction be sustained. Unless NASA has been really sneaky and hidden some explosives inside their RTGs, detonation is not possible. Using atmospheric pressure alone is not a viable explanation.

Now we can see that it is pretty much impossible for the plutonium on board Cassini to create a nuclear explosion. But if there was a nuclear detonation, could a chain reaction occur? Could Saturn become a star?

Find out in Part 2 of Project Lucifer: Will Cassini Turn Saturn into a Second Sun?

(A special thanks goes to Selene Spencer at Paranormal Radio for highlighting this topic on their website’s discussion forum.)

July 23, 2008December 24, 2015 by Nancy Atkinson

Phoenix in the Land of Mars’ Midnight Sun

Mars' Midnight Sun. Credit: NASA/JPL-Caltech/U of Arizona/Texas A&M University

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This panorama mosaic of images was taken by the Surface Stereo Imager on board NASA’s Phoenix Mars Lander. This mosaic documents the midnight sun during several days of the mission, from Sol 46, or the 46th day of the mission to Sol 56 (that would be to July 12 – 22, 2008 here on Earth.) The foreground and sky images were taken on Sol 54, when the lander pulled an all-nighter to coordinate work with the Mars Reconnaissance Orbiter. The solar images were taken between 10 p.m. and 2 a.m., local solar time, on the different nights of the 11 sol period. During this period, the sun’s path got slightly lower over the northern horizon, causing the lack of smoothness to the curve. This pan captures the polar nature of the Phoenix mission in its similarity to time lapse pictures taken above the Arctic Circle on Earth.

The latest activities of the lander has brought it closer to analyzing a sample of icy soil in the TEGA oven.

On Tuesday and Wednesday, Phoenix used its robotic arm to scrape the top of the hard layer in the trench called “Snow White.”

“We are monitoring changes between the scrapes,” said Doug Ming of NASA Johnson Space Center. “It appears that there is fairly rapid sublimation of some of the ice after scraping exposes fresh material, leaving a thin layer of soil particles that had been mixed with the ice. There’s a color change from darker to bluer to redder. We want to characterize that on Sol 58 to know what to expect when we scrape just before collecting the next sample.”

The science team is preparing to quickly collect a sample from the hard layer of Snow White and deliver it to one of the eight ovens of Phoenix’s Thermal and Evolved-Gas Analyzer (TEGA). Doors to the oven have been opened to receive the sample. TEGA will “bake and sniff” the samples to analyze the composition of the soil and ice.

On Wednesday the team also checked out the heater on TEGA is working properly, to verify that pressure sensors can be warmed enough to operate properly early in the Mars morning.

“For the next sample, we will be operating the instrument earlier in the morning than we have before,” said William Boynton of the University of Arizona, lead scientist for TEGA. “It will be almost the coldest part of the day, because we want to collect the sample cold and deliver it cold.”

On the day when Phoenix will deliver the next sample to TEGA, the team plans to have lander activities begin about three hours earlier than the usual start time of about 9 a.m. local solar time.

On Thursday, one set of imaging commands will check a northwestern portion of the horizon repeatedly during early afternoon to see whether any dust devils can be seen. This will be the first systematic check by Phoenix for dust devils. The Mars Rover Spirit was able to image sequences of dust devils in its location, south of Mars’ equator.

Original News Source: Phoenix News

July 23, 2008December 24, 2015 by Fraser Cain

Solar System Pictures

Diagram of the Solar System. Image credit: NASA

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This is a a diagram of the Solar System. It was released shortly before the International Astronomical Union made its final decision about whether Pluto should be a planet or not. In the end, they decided that Pluto is not a planet. But for a few days, it was possible that there would be 11 planets in the Solar System, including Pluto, Eris and the asteroid Ceres. This image of the Solar System shows them all with the Sun.

Pictures of all the objects in the Solar System. Image credit: NASA/JPL

This is a montage photo of the Solar System, with a picture of a Sun and all the planets, as well as all the moons in the Solar System. This lets you see just how many objects there really are in the Solar System.

Montage of the Solar System. image credit: NASA/JPL

This is another montage of the planets, dwarf planets, comets and asteroids in the Solar System. It’s one of the older Solar System pictures that we’ve seen.

Planets in the Solar System. Image credit: NASA/JPL/IAU

Here’s a Solar System image with all the planets correctly categorized. In this, we can see a picture of Pluto, Ceres and Eris are correctly designated as dwarf planets.

Want more images of planets? Here are some pictures of Mars, pictures of Venus, pictures of Saturn, pictures of Pluto, and pictures of Jupiter. Here’s an article about a 3D Solar System.

One of the best resources for photographs of the Solar System is NASA’s Planetary Photojournal. You can also check out Hubble’s photographs of the Solar System.

We have recorded a whole series of podcasts about the Solar System at Astronomy Cast. Check them out here.

July 23, 2008April 26, 2016 by Nancy Atkinson

What Are YOU Doing for the International Year of Astronomy?

In 1609, Galileo Galilei looked at the heavens through a telescope for the first time, and things on Earth haven’t been the same since. To celebrate the 400th anniversary of this advent of scientific discovery and thought, people and organizations from around the globe are coordinating a world-wide, year-long program called the International Year of Astronomy (IYA). Some of the goals of IYA are to stimulate worldwide interest in astronomy and science, especially among young people, to provide as many people as possible with an “astronomy experience,” and to support science education in both formal and informal settings. Currently, 118 countries are going to be part of IYA. The program has the support of the United Nations, the International Astronomical Union, the US’s National Science Foundation and all the space agencies around the world. Recently, the US House of Representatives passed a resolution supporting IYA. Right now IYA is in the planning and coordination stage. But for IYA to be a success, says Doug Isbell, one of the co-chairs for the US IYA program, it’s going to take a coordinated effort from volunteers around the world who want to share their love of space and astronomy. So, it’s time to start thinking about what YOU are going to do for IYA. And even though we’ve posted the IYA trailer on UT before, here it is again to help get you in the mood:

So, what’s in it for you? Plenty. There are a myriad of ways for everyone to get involved in IYA, whether its just attending a star party, or helping to coordinate a local event, or making a financial contribution.

One of the goals of IYA is to provide as many people as possible with the experience of looking through a telescope. Currently, IYA is designing a telescope kit, called the Galileoscope, to distribute to schools and science centers around the world. “We have a goal of approximately 1 million Galileoscopes world wide” said Isbell. “We want everyone to have a high quality, aha! experience. From networking and experience, we know that experience is something like being able to see Saturn’s rings. That drives you to a 40 or 45 power telescope, which is more ambitious than we originally thought.” The telescope kit will come with a educational curriculum, and is designed to be to be a science experience in either a classroom or an informal science center.

IYA would like to offer these scopes free to people around the world, and is looking for funding. “This is a big funding challenge,” said Isbell. “We’re getting close to the design, but we’re still looking for the chunk of money that will get us to the production phase.”

The overall US goal, said Isbell, is to offer an engaging astronomy experience to every person in the country in some fashion, whether it is in person or virtual, and to build partnerships for the future in educational outreach.

“Within the US, we have plans to foster star parties around the country, in coordination with local astronomy groups,” said Isbell. “There will be national and international efforts to observe particular objects, like Jupiter that will be in a good alignment in August of 2009. Also, we’re promoting the dark skies concept of preserving the night sky for observers, and we’re trying to foster a more formal research project to observe the variable binary star Epsilon Aurigae. It’s going through an eclipse that comes around every few decades, and this is a chance for the more dedicated observers and teacher/student researchers to study this star.”

One of the exciting events happening in conjunction with IYA is the production of a PBS special called “400 Years of the Telescope,” produced by Interstellar Studios, headed by Kris Koenig. Not only will there be a television special, but planetarium shows and interactive educational activities are being coordinated for as well for IYA. The 400 Years of the Telescope website has a newsletter available, which is also where you can find info on the US IYA effort. Subscribe to the newsletter here. UT will provide more information on “400 Years of the Telescope” as the air date gets closer.

Check out IYA’s website, which provides a centralized outlet for people to publicize and learn about events, activities and materials available online. Here’s the US IYA site. See how you can get involved. You can also find IYA on several of the social networking sites, like MySpace, and Facebook.

Universe Today will provide updated information about IYA, as well as details about the different facets of IYA in upcoming articles.

July 23, 2008December 24, 2015 by Fraser Cain

Diagram of the Solar System

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This image contains all of the largest objects in the Solar System. You can print this diagram of the Solar System, as well as this handy list of all the planets.

The Sun – The central star in the Solar System

Mercury – The first planet in the Solar System. It’s also the smallest planet in the Solar System. Mercury takes just 88 days to complete an orbit around the Sun.

Venus – The second planet from the Sun. In many ways, Venus is a twin to our own Earth. It has nearly the same size and mass as Earth, but the thick atmosphere on Venus makes surface temperatures hot enough to melt lead. Venus is also unusual because it rotates backwards to all the other planets.

Earth – Our home planet, the third planet from the Sun. Earth is the only planet in the Solar System known to support life. This is because we are at just the right distance from the Sun so that our planet doesn’t get too hot or too cold. We also have one moon – the Moon.

Mars – Mars is the fourth planet from the Sun, and is much smaller and colder than the Earth. Temperatures on Mars can rise to 20-degrees C, but dip down to -140-degrees C in the northern winters. Mars is thought to be the best candidate for life elsewhere in the Solar System. Mars has two small, asteroid-shaped moons: Phobos and Deimos.

Ceres – Ceres is the first dwarf planet in the Solar System, and the largest member of the asteroid belt.

Jupiter – Jupiter is the 5th planet from the Sun, and the largest planet in the Solar System. Jupiter has as much mass as 2.5 times all the rest of the planets combined – almost all of this mass is hydrogen and helium; although, scientists think it has a solid core. Jupiter has at least 63 moons.

Saturn – Saturn is the 6th planet from the Sun, and is well known for its beautiful system of icy rings. Saturn is almost as large as Jupiter, but it has a fraction of Jupiter’s mass, so it has a very low density. Saturn would float if you could find a tub of water large enough. Saturn has 60 moons at last count.

Uranus – Uranus is the 7th planet from the Sun, and the first planet discovered in modern times; although, it’s just possible to see with the unaided eye. Uranus has a total of 27 named moons.

Neptune – Neptune is the 8th and final planet in the Solar System. Neptune was only discovered in 1846. It has a total of 13 known moons.

Pluto – Pluto isn’t a planet any more. Now it’s just a dwarf planet. Pluto has one large moon, called Charon, and then two smaller moons.

Eris – The next dwarf planet in the Solar System is Eris, which was only discovered back in 2003. In fact, it was because of Eris that astronomers decided to reclassify Pluto as a dwarf planet.

I hope you find this diagram of the Solar System helpful.

Reference:
NASA Solar System Exploration Guide

July 23, 2008December 24, 2015 by Nancy Atkinson

This Week’s “Where In The Universe” Challenge

It’s Wednesday, so that means its time for another “Where In The Universe” challenge to test your visual knowledge of the cosmos. Guess the location of this image, and give yourself extra points if you can name the spacecraft responsible for the photo. Remember, you have 8 planets, 169 known moons, a handful of dwarf planets (there’s a new one!) and lots of asteroids in our solar system to choose from. We’re also up to over 300 known exoplanets now; however we don’t have the capability to image them quite yet, so you can cross them off your potential answer list. Don’t cheat – make your guess before you look below!

On October 13, 2000, the Expedition 3 crew of the International Space Station, took this interesting photo of the Brahmaputra River in Tibet. This river carves a narrow west-east valley between the Tibetan Plateau to the north and the Himalaya Mountains to the south, as it rushes eastward for more than 1,500 km in southwestern China. The 15-km stretch shown here is about 35 km south of the ancient Tibetan capital of Lhasa. As you can see the river flow becomes intricately braided as it works and reworks its way through extensive deposits of erosional material. This pattern indicates a combination heavy sediment discharge from tributaries and reduction of the river’s flow from either a change in gradient or perhaps even climate conditions over the watershed. The area is also known for strong, persistent westerly winds which also shapes the region.

Photos such as this one bring immediate visual understanding and appreciation of natural processes in some of the most remote locations on Earth.

How did you do?

More info on this image.

July 23, 2008April 26, 2016 by Nancy Atkinson

New “Sunglasses” Help Astronomers See Light Near Black Holes

Looking at the sunset on Mauna Kea through IRPOL. Credit: U of Hawaii

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Although we can’t actually see a black hole, we can see the black hole’s effect on nearby matter. But even that is difficult because infrared light from clouds of dust and gas usually pollutes the view. But astronomers have found a way to get a clean view of the disks surrounding black holes by using a polarizing filter in the infrared. This technique works in particular when the region immediately surrounding the black hole emits a small amount of scattered light. Since scattered light is polarized, astronomers can use a filter that works like polarized sunglasses on large telescopes to detect this small amount of scattered light and measure it with unprecedented accuracy. Scientists have theorized these luminous disks existed around black holes, but until now have not been able to observe them.

The United Kingdom Infrared Telescope (UKIRT) on Mauna Kea in Hawaii has such an infrared filter, called a polarimeter (IRPOL). Astronmers have been using UKIRT and IRPOL and other telescopes for many years to search for proof that such a luminous supermassive black hole is accreting materials in a particular form of disk, where the disk shines directly using the gravitational binding energy of the black hole. Theorists have long thought that such disks should exist, and while there is a well-developed theory for it, until now theory and observations have been contradictory.

Dr. Makoto Kishimoto of the Max Planck Institute, principal investigator of this project, says: “After many years of controversy, we finally have very convincing evidence that the expected disk is truly there. However, this doesn’t answer all of our questions. While the theory has now been successfully tested in the outer region of the disk, we have to proceed to develop a better understanding of the regions of the disk closer to the black hole. But the outer disk region is important in itself – our method may provide answers to important questions for the outer boundary of the disk.”

A polarizing filter allows the colors of disk to be seen. Figure by M. Kishimoto, with cloud image by Schartmann

Dr. Robert Antonucci of the University of California at Santa Barbara, a fellow investigator, says: “Our understanding of the physical processes in the disk is still rather poor, but now at least we are confident of the overall picture.”

Astronomers are hoping this new method will provide more information about the disks surrounding black holes in the near future.

Now, next on the agenda should be developing a suitable gravitational wave detector to confirm the existence of black holes!

Original News Source: University of Hawaii

July 23, 2008December 24, 2015 by Nancy Atkinson

Ancient Galactic Magnetic Fields Stronger than Expected

Spiral galaxy M 51 with magnetic field data. Credit: MPIfR Bonn

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The origin of magnetic fields in our universe is a mystery. But magnetic fields are a key part of the interstellar medium and scientists are finding they may play a major role in galactic formation, such as helping to form the spiral arms of galaxies. Until recently, however scientists believed the strength of galactic magnetic fields increased over time as galaxies matured, and in the early universe, these magnetic fields were initially very weak. But, recently a team of scientists looking back to probe the ancient universe as it existed 8 to 9 billion years ago has found that the magnetic fields of ancient galaxies were just as strong as they are today, prompting a rethinking of how our galaxy and others may have formed.

Using the European Southern Observatory’s 8-meter telescope located in Chile, a team of scientists from the Los Alamos National Laboratory and the Swiss Federal Institute of Technology studied 70 galaxies similar to the Milky Way at optical wavelengths. They combined their data with 25 years of radio wave observations of magnetic fields that measured how far the radio waves were pulled toward the red end of the spectrum, known as “redshift” using Faraday rotation measures.

Serving as a looking glass into the past, the powerful telescope at the European Southern Observatory, adding to the radio rotation measures, allowed the scientists to observe surprisingly high magnetic fields between 8 billion and 9 billion years ago in the 70 galaxies studied. That means that several billion years before the existence of our own sun, and within only a few billion years of the Big Bang, ancient galaxies were exerting the tug of these strong magnetic fields.

“It was thought that, looking back in the past, earlier galaxies would not have generated much magnetic field,” said Philipp Kronberg of LANL. “The results of this study show that the magnetic fields within Milky Way-like galaxies have been every bit as strong over the last two-thirds of the Universe’s age as they are now-and possibly even stronger then.”

Astronomers had thought a mechanism called a dynamo, which transfers mechanical energy into magnetic energy was responsible for galactic magnetic fields. In that case, with the right configuration gas flow could generate a higher magnetic field from a weaker seed field. (Again, we have yet to understand how galactic magnetic fields originally form.) But this new research suggests that the magnetic fields in galaxies did not arise due to a slow, large-scale dynamo effect, which would have taken 5 billion to 10 billion years to reach their current measured levels.

“There must be some other explanation for a much quicker and earlier amplification of galactic magnetic fields,” Kronberg said. “From the time when the first stars and galaxies formed, their magnetic fields have probably have been amplified by very fast dynamos. One good possibility is that it happened in the explosive outflows that were driven by supernovae, and possibly even black holes in the very earliest generations of galaxies.”

This realization brings a new focus on the broader question of how galaxies form. Instead of the commonly held view that magnetic fields have little relevance to the genesis of new galaxies, it now appears that they are indeed important players. If so, strong magnetic fields a long time ago are one of the essential ingredients that explain the very existence of our galaxy and others like it.

Original News Source: Los Alamos National Lab

July 22, 2008December 24, 2015 by Ian O'Neill

Polaris Brightness Variations are Revived, Astronomers Mystified

Polaris A (Pole Star) with its two stellar companions, Polaris Ab and Polaris B. Polaris itself is a Cepheid type variable star. Artists impression. Credit: NASA

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Polaris is a well known Cepheid variable, but its periodic brightness variations have been steadily decreasing in amplitude for the last hundred years. Around the beginning of the 20th Century, Polaris’ brightness fluctuated every four days by 10%. Only ten years ago this variation had dropped to 2%, leading astronomers to believe this steady decline in the variability of the star was about to end. That was until recent observations uncovered an increase in variability to 4%. Polaris is an odd star in that it is a Cephid variable with a declining variability, and now astronomers are baffled as to why the brightness fluctuation has been revived…

Polaris (a.k.a. the North Star or Pole Star) has helped mankind navigate the globe since ancient times. Always positioned around the North Polar axis of the Earth, Polaris has also provided material for literature, poetry and religion. In astronomical terms it is also significant as it is a Cepheid variable with a regular variation in brightness, although it is the only Cepheid variable known that has been decreasing in brightness for the last several decades. But to complicate matters even further, this Type 1a supergiant (approximately 4-5 solar masses and 30 solar radii) appears to have been rejuvenated, and the vibrations have increased, varying in brightness by 4 %.

This discovery comes after observations made by Hans Bruntt from the University of Sydney and his international collaboration. Dr Alan Penny, co-investigator from the University of St. Andrews, UK, will present the team’s findings at his university’s “Cool Stars 15” conference this week.

In reality, the astronomers had focused their attention on Polaris in the hope to catch the point at which its variations ceased completely, only to find they had increased. “It was only through an innovative use of two small relatively unknown telescopes in space and a telescope in Arizona that we were able to discover and follow this star’s recovery so accurately,” Penny said. He was using the SMEI space camera, usually applied for solar-terrestrial observations of the solar wind, but he used it to accurately survey the night sky for Cepheid variables. At the same time, Bruntt was using a small telescope attached to NASA’s retired infra-red space telescope (WIRE) set up to study Polaris for a short period. When Penny noticed the strange recovery of Polaris in his SMIE data, it was compared with Bruntt’s WIRE data. It was therefore confirmed that Polaris’ vibrations had been revived.

Decrease over 100 years of amplitude of 4-day light variation of Polaris and of the increase since 2000. Credit: H. Bruntt et al. 2008

Backing up Penny and Bruntt, Professor Joel Eaton (Tennessee State University), who was using the AST automated spectroscopic telescope located in Arizona, noticed variations in the plasma velocity on the surface of Polaris. These measurements showed the brightness variations were correlated with expansion and contraction effects through the body of the star.

These observations are both exciting and perplexing. Although the variations observed in Cepheid variables are poorly understood, the vast majority of these “standard candles” do not change in brightness, let alone revive themselves. It would appear Polaris is undergoing a change that isn’t predicted by the standard model for stellar evolution, so the team of astronomers will be quick to follow up these observations with some theory as to what is causing the changes inside Polaris…

Sources: Physorg, arXiv

July 22, 2008December 24, 2015 by Fraser Cain

Model of the Solar System

Everyone seemed to enjoy the answer to my daughter’s question, “what’s the biggest star?”, so I thought I’d give you another insight into space science at the Cain household. A couple of months ago, we built a scaled map of the Solar System. I thought I’d share my process and resources with you, and throw in a few cute pictures of the kids. So come on, let’s build a solar system scale model in your neighborhood. And for those who might be interested, we also put up links of amazing Solar System collectibles from Amazon.com. Your kids will surely enjoy them!

This project happened when I casually mentioned to Chloe that it might be fun to build a scale model of the solar system. You know, some day, when we had time. Chloe and Logan thought it was a great idea, and even though there was half a metre of snow on the ground, it had to happen… right now!

We decided that we wanted to put the Sun in Chloe’s room, and then put all the planets to scale, so that we could walk to Chloe’s school (about a kilometer away), and have all the planets fit nicely – we even included Pluto (which will always be a planet in our hearts).

I found a great calculator that lets you calculate various scale model versions of the Solar System. You put in the size for the Sun and then it calculates both the diameters of the scale model versions of the planets, as well as the scale distances.

We were really fortunate. A version of the Solar System scale model that fit within the distance from our house to Chloe’s school allowed for a Sun that could be cut out of a single sheet of printer paper. I used a protractor to measure out the circle for the Sun, and then cut it out. While the kids were colouring it yellow, I made tiny versions of all planets.

Here are the sizes:

Object	Size (mm)	Size(in)
Sun	200	7.8
Mercury	0.6	0.0275
Venus	1.7	0.0684
Earth	1.8	0.072
Mars	0.9	0.0382
Jupiter	20	0.7892
Saturn	16.7	0.6586
Uranus	6.7	0.2655
Neptune	6.5	0.257
Pluto	0.3	0.012

Then we put our mock planets out into their proper orbits using clear sticky tape. With the Sun just inside Chloe’s room, Mercury was at the top of the stairs. Venus was just outside our front door. Earth at the end of our sidewalk. Mars is on a parking sign across the street from our front door. Jupiter is part way down the next block, stuck to a tree. Saturn is on another tree further down that same block. Neptune is on a parking sign 2 blocks further. Uranus is on a fire hydrant. And finally, tiny Pluto was affixed to a power pole just in front of Chloe’s school.

If you want to get really clever, you can even put in tiny moons. For example, you could put in the moons of Pluto: Charon, Nix and Hydra.

Here are the kids with Mars. Look closer, it’s there.

Here are all the distances:

Object	Distance (m)	Distance (feet)
Sun	0	0
Mercury	8	27
Venus	15	51
Earth	21	71
Mars	32	107
Jupiter	111	367
Saturn	205	673
Uranus	412	1353
Neptune	647	2121
Pluto	850	2787

I was fairly careful measuring distances for the inner planets. But then I just made a rough estimate of my stride length, and used that to mark off the longer distances. Here’s a link to a stride length calculator.

It’s scary to think that a version of Alpha Centauri at this scale would still be 5804.4 km (3606.7 miles) away. That would require a road trip across Canada.

And, now, every day that I walk Chloe to school, we follow the route of our miniature Solar System, and think about just how big the place really is. Even though it’s been a few months since we made our model, most of the planets are still there (we lost Saturn a few weeks back, but we’ll replace it).

Have you built a Solar System scale model for a school project? Let me know how it went and send pictures. Maybe I’ll do a follow up with some more astronomy project ideas.

For extra credit, get your kids to model some of the recently discovered extrasolar planets. Here’s a page that lists their sizes and distances from their parent stars. With so many hot jupiters out there, you could fill a wall with scale versions.

If your kids want to learn more about the Solar System, listen to Astronomy Cast. We did a special tour through each of the planets in the Solar System. Start your tour here with Mercury, then Venus, Earth, Mars, the Asteroid Belt, Jupiter, Jupiter’s Moons, Saturn, Saturn’s Moons, Uranus, Neptune, Pluto, and then the outer reaches of the Solar System.