Diagram of the Solar System

Diagram of the Solar System. Image credit: NASA

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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

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.

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
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

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

Polaris Brightness Variations are Revived, Astronomers Mystified

Polaris
Polaris A (Pole Star) with its two stellar companions, Polaris Ab and Polaris B. 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.

H. Bruntt et al. 2008
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

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.

Solar System Model

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.

What is the Solar System?

Pluto and the rest of the Solar System. Image credit: NASA

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The Solar System consists of the Sun, and everything bound to it by gravity. This includes the 8 planets and their moons, the asteroids, the dwarf planets, all the Kuiper belt objects, the meteoroids, comets and interplanetary dust. Since the gravitational effects of the Sun are thought to reach out almost 2 light-years away – almost half the distance to the next star – there could be any number of objects out there, as part of the Solar System.

There are separate regions in the Solar System. First, there’s the Sun, of course. Then there are the inner terrestrial planets: Mercury, Venus, Earth, and Mars. Then comes the asteroid belt; although, not all the asteroids are located in this region. The largest dwarf planet, Ceres, is located in the asteroid belt. Then come the outer gas giants: Jupiter, Saturn, Uranus, and Neptune. Then comes the Kuiper Belt, which includes 3 more dwarf planets: Pluto, Makemake, and Eris. Beyond the Kuiper Belt is thought to be the Oort Cloud, which could extend out to a distance of 100,000 astronomical units (1 AU is the distance from the Sun to the Earth).

Between the planets are smaller objects which never formed a planet or moon. This can range from microscopic dust, up to asteroids hundreds of kilometers across. Beyond the orbit of Neptune, much of this material is icy.

The solar wind emanating from the Sun blasts through the Solar System, interacting with the planets, and pushing material out into interstellar space. The region where this solar wind blows is called the heliosphere, and where it stops is called the heliopause.

The immediate neighborhood around the Solar System is known as the Local Interstellar Cloud. It has high-temperature plasma that suggests that there were nearby supernovae.

The closest star to the Solar System is the triple star system Alpha Centauri.

Are you wondering how many planets there are in the Solar System, or what is the biggest planet in the Solar System?

One of the best pages about the Solar System is the Nine Planets, and Kids Astronomy has more info for kids.

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

Carnival of Space #63

Wall-E vs Opportunity

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Another new host for the Carnival of Space. This week, the whole carnival moves to the home of the Angry Astronomer.

Click here to read the Carnival of Space #63

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.

Podcast: Quasars



Last week we talked about galaxies in general, and hinted at the most violent and energetic ones out there: active galaxies. Quasars have been a mystery for half a century; what kind of object could throw out more radiation than an entire galaxy? A black hole, it turns out, with the mass of hundreds of millions of suns performs this feat. Let’s trace back the history of quasars, how they were first discovered and puzzled astronomers for so long. And let’s look at what we know today.

Click here to download the episode

Quasars – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Book Review: Floating to Space

Floating to Space.

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America’s OTHER space program is how John Powell bills his airship to orbit program. This endeavour, wonderfully encapsulated in his book Floating to Space, describes a less than typical application of a well-known technology. Using the concept of dynamic climbing, he believes and shows that airships are the better method to putting people and material into space.

Airships aren’t new. The Montgolfier brothers made the first modern edition and, since then, lighter-than-air transportation has been used to make determinations of weather in high latitudes, as well as to film sports events. Effectively, by trapping a less dense gas within an envelope, the envelope and a payload ascend. John Powell is fine tuning this concept for travelling into orbit and plans to soon elevate appreciable payloads to above 400 kilometres. And, as we all know, at that height, space travel becomes quite achievable.

Given this unconventional concept, Powell’s book follow the standard fare of all space dreamers. Like these, his book starts by admonishing the reader to accept physics and forgo tradition. Next, he justifies his beliefs by providing a review history. For example, did you know that the Nazca drawings might have been directed by a fellow in a hot air balloon? Continuing on, he provides a rational description of the current abilities of airships and their kin and ably convinces the reader that airships have got potential.

Now, if the reader perseveres through this brief background, they will get into the really exciting stuff. For it seems that John Powell is as much an engineer as he is a dreamer. Having amassed more than 80 missions over the previous 15 years, he can draw upon real experience and he does so in presenting the reader with steps he’s made of real progress. For example, during the early times he describes shooting rockets from balloons, nicknamed rockoons. Toward the end, he describes how he’s now floating platforms to above 100 000 feet. This story would warm any engineer’s heart. The technical progress described would set their hearts on fire.

Complementing the book is an enclosed DVD that is part documentary and part fanfare. In it, Powell’s placed some choice video taken from payloads as they climb to way-up-high and other videos that show a quite rapid descent from the same height. Equally exciting segments include footage of the next generation craft, Ascender 90, with ‘wings’ over 90 feet in length. It gently rises massively above a hanger floor as if coming to life for the first time. Given that this is a taste of things to come, this book is a wonderful place marker of what’s happened to date in Powell’s program and where things will hopefully be going.

In sum, this book’s got the touch of a visionary and the feel of a practitioner. It showcases a small cadre of people working against the grain of the norm. Yet, similarly, their goal is to achieve a great benefit for everyone. Optimism exudes from the pages as do technical triumphs. And, success just seems around the corner so that the reader may feel themselves getting drawn into the excitement and look to contribute.

Though not as flashy as rockets, airships provide similar capabilities. Both loft massive payloads up above the atmosphere. John Powell’s book Floating to Space – The Airship to Orbit Program shows the feasibility of this endeavour as well as results of his own efforts. With time, it seems, this program is destined for a lofty future.

Read more reviews online, or purchase a copy from Amazon.com.