Universe Today

April 26, 2008February 6, 2017 by Fraser Cain

Temperature of Pluto

Pluto's temperature makes it one of the coldest places in the Solar System.

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With such a large distance from the Sun, Pluto is incredibly cold. But this temperature can vary enough to change the dwarf planet significantly. At its closest point, it warms up enough so that Pluto’s nitrogen atmosphere sublimates and forms a diffuse cloud around it. As Pluto gets further away from the Sun; however its this atmosphere freezes out, and falls to the surface of Pluto like snow.

First, let’s define some measurements. Room temperature is considered 21-degrees Celsius or 70-degrees Fahrenheit. The freezing point of water is 0-degrees Celsius or 32-degrees Fahrenheit. But when you’re measuring temperatures on Pluto, you really want to use Kelvin.

Zero Kelvin is the absolute zero temperature; a theoretical maximum point where no more energy can be extracted from a system. 0-degrees Kelvin corresponds to -273-degrees Celsius.

The surface of Pluto, in comparison, can range from a low temperature of 33 Kelvin (-240 degrees Celsius or -400 degrees Fahrenheit) and 55 Kelvin (-218 degrees Celsius or -360 degrees Fahrenheit). The average surface temperature on Pluto is 44 Kelvin (-229 Celsius or -380 Fahrenheit).

Back in the days when Pluto was still a planet, it was the coldest planet in the Solar System. But now it’s just a regular temperature dwarf plant – poor Pluto. Neptune is now the coldest planet.

April 26, 2008December 24, 2015 by Fraser Cain

Distance to Pluto

Pluto has the most elliptical orbit of all the planets and dwarf planets. In addition to this widely varying orbital distance, Pluto is also highly inclined, orbiting above and below the planet of the ecliptic that the rest of the planets follow.

You can also look through these books from Amazon.com if you want more information about Pluto.

Pluto Distance from the Sun
Since Pluto orbits the Sun, like the rest of the planets and dwarf planets, astronomers typically measure the distance of Pluto in terms of Astronomical Units (AU). 1 AU measures the distance of the Earth to the Sun.

At its closest point, Pluto is only 29 astronomical units from the Sun (4.4 billion km or 2.75 billion miles). And at its most distant, it can be 49 AU (7.29 billion km, or 4.53 billion miles) from the Sun. In addition to being highly elliptical however, Pluto’s orbit is also inclined at an angle of over 17-degrees. At some points along its orbit, Pluto is above the plane of the ecliptic that the planets follow, and at other times, it’s below.

Pluto’s average distance from the Sun is 40 astronomical units (5.91 billion km or 3.67 billion miles).

Distance From Earth to Pluto
The Earth is only 1 AU from the Sun. When the Earth and Pluto are perfectly lined up with the Sun, their closest point is approximately 28 astronomical units. And at their furthest point, when Earth is on the opposite side of the Sun, Pluto can be 50 astronomical units.

April 25, 2008December 24, 2015 by Ian O'Neill

ATV Jules Verne Boosts Space Station to Higher Orbit (Video)

For the first time since docking with the International Space Station (ISS) on April 3rd, the Automated Transfer Vehicle (A T V) “Jules Verne” has been awoken and instructed to carry out an impressive task: push the ISS to a higher orbit. The robotic supply vessel, currently attached to the station’s Zvezda module carried out a 12 minute 20 second burn of its main engines. This is the first time an ESA spaceship has carried out such a task and it appears to have performed flawlessly, lifting the 280 tonne station 4.5 km (2.8 miles) to a new altitude of 342 km (213 miles). In true ESA style, they’ve even released a cool video simulation of the event…

Periodically, the ISS needs a small push in the right direction. As the station orbits Earth, it experiences a small amount of friction from the extended atmosphere of our planet. This atmospheric drag slows the orbiting outpost, making it drop to a lower orbit. When needed, the ISS must to be pushed to higher altitudes. Until now, “re-boosts” have been performed by the Space Shuttle, Russian Progress and by the ISS itself; but today, it was the turn of the most advanced European spacecraft ever put into space. Due to the large quantities of fuel still on board, Jules Verne is ideal for this manoeuvre.

At 04:22 GMT Friday morning, two of the four powerful ATV rockets burst to life after being given the signal from mission control in Toulouse, France. The supply ship provided a thrust of 2.65 m/s, accelerating the ISS along its orbital path. This increased speed increased its orbit. Mission controllers carefully monitored events for the long 740 seconds.

See the ESA video simulation of the ATV re-boost »

This re-boost comes after three weeks of inactivity for the ATV. The unmanned cargo vessel was launched on March 9th to take 1150 kg (2535 lb) of water, food and other supplies to the ISS. This proved to be a very busy time for space traffic control. First the ATV was launched, then on March 11th Space Shuttle Endeavour was sent on her way, then on April 8th Soyuz ISS 16S was launched. Jules Verne drew the short straw and had to wait in a parking orbit until Endeavour had docked, carried out its mission and then returned home. The ATV used this time to run tests until it was cleared for docking on April 3rd.

Now the ISS is ready for the arrival of Space Shuttle Discovery (STS-124) scheduled for launch at the end of May. Discovery will deliver the Japanese Kibo laboratory to be installed on the growing station. Another three re-boosts are planned for the ATV on June 12th, July 8th and August 6th. Shortly after the last boost, Jules Verne is destined to be detached from the Zvezda module and dropped into the atmosphere, carrying 6.5 tonnes of trash into a controlled re-entry burn over the Pacific Ocean. A sad end to an amazing piece of technology.

Source: ESA

April 25, 2008December 24, 2015 by Ian O'Neill

Space Golf and Other Zero-G Sports on the ISS

Cosmonaut Sergei Krikalev practices his swing on the station in 2005 (Element 21 Golf Company)

Humans and sports go hand-in-hand; it was only a matter of time before sports pushed into space. Whether astronauts are practicing their cosmic golf swing, throwing boomerangs (for science of course!), hurling footballs or creating their own unique zero g activity, we will see some new and inventive space sports in the future…

Launched on board Apollo 14 in February 9th, 1971, astronaut Alan Shepard had brought a little extra weight with him. A golf club and golf balls. He wanted to be the first to play golf on the dusty surface of the Moon. His dream became a reality, doing a one-handed drive, blasting the ball over 200 yards during one of his Moon walks. Not bad considering how restrictive his space suit must have been (although the 1/6 Earth gravity will have helped the ball along a little). Shepard held the extra-terrestrial golf drive record for 35 years until cosmonaut Mikhail Tyurin shattered the record with a million-mile hit from the International Space Station in 2006 (it was actually a miss-hit, but mission scientists think it orbited the Earth for 2-3 days before falling into the ultimate hazard… the Earth’s atmosphere).

In fact, the International Space Station astronauts have tried out a variety of sports. An average ISS astronaut’s day consists of six and a half hours of work, two hours for exercise and about eight and a half hours for sleep. Naturally, as we do on Earth, the orbiting men and women have some time to fill with personal activities, including sport. A lot of the time, the odd dabble with a boomerang and a session on the treadmill has a scientific merit, but some of the sporting activities were done simply for fun. In the case of Tyurin, sport may also be a marketing stunt (the ISS golf driving range was set up by Canadian golf club manufacturer Element 21) – but I’m sure he had a special sense of satisfaction teeing off the high altitude location.

Zero-G offers many options for new sports too. In a televised interview last week, NASA astronaut Garrett Reisman (who is currently residing on the station as the Expedition 17 flight engineer) admitted to finding the mundane task of filling up large water bags rather enjoyable:

“We started tossing them kind of like a medicine ball, and we realized that you could toss and catch and then go for a ride on this big thing as it takes you away. So there’s all kinds of possibilities, and if there’s any good ideas out there, let me know. We’ll try it.” – Reisman.

Whilst this may not constitute a “sport”, it could be a fun game. When the Expedition 16 and 17 crews overlapped, there were six crewmembers to participate in the orbital fun. Record breaker Peggy Whitson commented on a relay race that the crew had through three of the station modules. “We raced from one end of a module, relayed with the person waiting at the other end three modules away, and then sprinted back and sent a third person,” Whitson said. “So it was pretty fun.” Apparently her team (including Reisman) won.

Although the ISS astronauts may not have many sporting options at their disposal, mission control makes sure they don’t get bored. They have a treadmill and stationary bike, and they’ve played weightless basketball, Frisbee and thrown boomerangs. Plus the odd round of golf it seems. Even throwing away the garbage seems like a superb way to pass the time. Have a look at this NASA video of the station crew having way too much fun in orbit (I do admit, I am very jealous!).

All these activities are going on in the space station not exactly built for sporting activities. With the advent of space tourism, it’s not hard to envisage the development of space sports, perhaps in orbital space hotels with large volumes of space available for sports activities. One such sport could be the possibility of zero-G dodgeball (pictured). This was already attempted on board Boeing 727-200 jets operated by the Zero Gravity Corp. (Las Vegas). Although periods of weightlessness would have been short, it must have been fun.

Original source: Space.com

April 25, 2008April 26, 2016 by Ian O'Neill

Potential Global Warming “Fix” Will Damage the Ozone Layer

There are many possible “geo-engineering” solutions open to scientists in the aim to stave off global warming. One of the main candidates to dim the solar energy input to the atmosphere is to inject huge quantities of sulphate particles high in the atmosphere. This mimics the emissions from a large volcanic explosion proven to cool the Earth’s atmosphere in the past. But, you guessed it, there’s a problem. New research suggests that tampering with the atmosphere in this way will have serious repercussions for the ozone layer… Now there’s a surprise!

On writing this week’s Carnival of Space, I came across an interesting discussion about the damage that can be caused by scientists tampering with weather. Nancy L. Young-Houser takes the strong view that under no circumstance is it OK to alter natural weather processes, even if the purpose is to advert a catastrophic hurricane or bring rain to drought-ridden regions. Looking at historic examples of cloud seeding for example, Nancy concludes that weather manipulation is not only morally but ethically wrong. There will always be a loser.

Then today, the BBC ran an article on the perils of using high altitude particles to block sunlight from entering our atmosphere. The effect of such a large-scale measure could emulate the ejected particles from a huge volcanic explosion. Sulphide particles are known to be a highly efficient means to deflect sunlight, thus cooling our atmosphere, possibly saving us from the ravages of our self-inflicted global warming. (This effect was observed in the 1991 eruption of Mount Pinatubo, pictured.) But there is a big flaw in this plan according to new research published in Science. Sulphide particles can damage the ozone layer, possibly creating another hole in the ozone over the Arctic and undo the recovery of the Antarctic ozone hole, setting it back decades.

Dr Simone Tilmes of the National Center for Atmospheric Research (NCar) in Boulder, Colorado, and her team analysed data and ran simulations of the sulphide effect on the atmosphere. Their conclusion? Injecting sulphide particles into the high atmosphere may lessen the effects of global warming, but it will also set back Antarctic ozone layer recovery 30 to 70 years. Sulphates are ideal particles on which atmospheric chlorine gases held in polar clouds will attach themselves to (pictured top). A chemical reaction between sulphate particle and chlorine destroys ozone molecules (O₃). The effects of this chemical reaction may cause accelerated damage in troubled polar regions. This ozone depletion was also recorded after the Mount Pinatubo eruption.

Attempting to “repair” the global damage we are causing to the atmosphere by injecting even more particles at high altitudes may not be the best way forward. After all, as outlined in Nancy’s article, there are many hidden risks when geo-engineering our atmospheric dynamics. Perhaps working on the reduction in greenhouse gas emissions may be a better idea, sooner rather than later.

Source: BBC

April 25, 2008 by Fraser Cain

Trailer for the International Year of Astronomy 2009

Okay, now I’m getting excited. As I’ve mentioned in the past, and will bring up again and again, the UN has designated 2009 as the International Year of Astronomy. There are some really great projects planned that will try to get as many people as possible interested in astronomy. The IYA has released a cool trailer to get us all inspired. It’s working for me.

April 25, 2008December 24, 2015 by Fraser Cain

What is Pluto Made Up Of

No longer a planet, Pluto is just a member of the Kuiper Belt; a collection of icy objects that extend out past the orbit of Neptune. If you brought Pluto into the inner Solar System, it would start to act like a comet – blasting out gas and particles from the solar wind. It’s a good thing Pluto is in the cold, dark outer Solar System, far away from the Sun.

So, if it would act like a comet, what is Pluto built of, and how do we even know? Pluto is so small and dim that only the largest telescopes can see it. To even see with your own eyes, you want a 30 cm (12 inch) telescope – and then you’ll only see a dot.

Astronomers using the world’s biggest telescopes, including the Hubble Space Telescope see a much better view. By using a technique called spectroscopy, astronomers can analyze the details about Pluto’s surface. The current thinking is that it’s composed of more than 98% nitrogen ice, with traces of methane and carbon monoxide.

The limits of telescope technology mean that we can’t get a better view of Pluto’s surface. But NASA’s New Horizons spacecraft is making the journey to Pluto, and will make a flyby in 2015. At that point, it will fly within 10,000 km of Pluto’s surface and send back images that show features as small as 1.6 km across. This will be a tremendous improvement over our current understanding of Pluto.

But what’s inside?

Planetary scientists have calculated Pluto’s density at between 1.8 and 2.1 g/cm³. From this density, they have calculated that its interior is probably 50-70% rock and 30-50% ice. Decaying radioactive elements inside Pluto would heat the interior of the dwarf planet, allowing the rock and ice to move around. At this point, the interior of Pluto is probably a rocky core surrounded by a shell of ice. If the radioactive elements are still decaying today, they could heat Pluto up enough that it has an interior liquid ocean, like Jupiter’s moon Europa.

The surface of Pluto is a thin layer of nitrogen, methane and carbon monoxide. When Pluto is at its closest to the Sun, this material evaporates, and forms an atmosphere around the dwarf planet. And then, when it’s further from the Sun, and cooler, this atmosphere freezes back down onto the surface.

Here are some nice Pluto images.

Source: NASA

April 25, 2008December 24, 2015 by Fraser Cain

Pluto Atmosphere

Artist's impression of a comet's surface. Image credit: NASA/JPL

Yes, that’s right, Pluto does have an atmosphere. Well, the Pluto atmosphere is not the ocean of air we have here on Earth, but Pluto’s thin envelope of gases do surround the dwarf planet for part of its orbit around the Sun.

You can also look through these books from Amazon.com if you want more information about Pluto.

It’s important to understand that the orbit of Pluto is very elliptical, bringing it closer and then more distant at various points of its orbit. At the closest point, the surface of solid nitrogen heats up enough that it sublimates – changes directly from a solid to a gas.

These clouds of nitrogen surround Pluto, but it doesn’t have enough gravity to keep them together, so they can escape out into space.

And then, as Pluto gets further from the Sun again, it cools down, and the atmosphere freezes and solidifies back down on the surface of Pluto.

In 1988, astronomers discovered that Pluto has an atmosphere by watching how it passed in front of a more distant star – called a planetary transit. Instead of dimming the moment it went behind Pluto, the star was first obscured by the atmosphere, so that astronomers could measure its thickness and composition.

It currently has 3Î¼bar on the surface and its height extends 60 km above the surface.

More precise observations were done in 2002, when astronomers were surprised to find that Pluto’s atmosphere had actually thickened since it had first been discovered. Astronomers think this is a seasonal phenomenon. The nitrogen on Pluto’s surface was exposed to sunlight following a 120-year winter. The nitrogen became a gas, but it took time to get going as an atmosphere.

As Pluto is now traveling away from the Sun, the Pluto atmosphere won’t last long. Astronomers think it will begin to disappear by 2015. This is one of the big reasons NASA sent its New Horizons spacecraft – to study Pluto’s atmosphere before it’s gone for good.

April 24, 2008December 24, 2015 by Fraser Cain

Moons of Pluto

When Pluto was first discovered back in 1930, astronomers thought it was just a single, solitary planet orbiting the Sun. Almost 50 years later, astronomers discovered that it actually had a very large moon. And then in 2005, astronomers working with the Hubble Space Telescope announced that they had found two more moons of Pluto, officially named Nix and Hydra. Are there more, waiting to be found? How many moons does Pluto have?

Astronomers now know that Pluto has three natural satellites. The first and largest of the Pluto moons is Charon, first identified back in 1978 by astronomer James Christy. He made the discovery while examining a photograph of Pluto and noticed that it had a bulge on one side. Christy and his colleagues thought this bulge came from a defect in the alignment of the telescope, but then they noticed that only Pluto was elongated, and not the background stars. They realized they were looking at a moon for Pluto.

Pluto’s moon Charon is named after the boatman in Greek mythology who guides the dead across the River Styx. This works well, considering Pluto is the roman god of the underworld (no, not the Disney Dog).

Charon is large and massive, compared to its parent dwarf planet Pluto. While Pluto measures 2,306 km across, Charon is 1,205 km.across.

One of the remarkable things about Pluto and Charon is that they’re actually a binary system. The two objects orbit a common center of gravity which is outside Pluto itself. For comparison, the Earth and Moon’s center of gravity is inside the Earth.

Back in 2005, astronomers working with the Hubble Space Telescope discovered two additional Pluto moons; they named them Nix and Hydra (originally S/2005 P1 and S/2005 P2). Nix measures 46 km across, and Hydra is 61 km. The Hubble research suggested a n upper limit for moon sizes orbiting Pluto. It appears that Pluto has already reached this limit with Nix and Hydra, and anything larger would be clearly visible.

The discovery of these moons has given hope to the theory that Pluto has a ring system, created with micrometeorites impact with the surface of the dwarf planet. Another possibility is that Charon produces ice geysers, similar to Saturn’s moon Enceladus.

More on this will be discovered when NASA’s New Horizons spacecraft finally arrives at Pluto in 2015. At its closest point, New Horizons will get within 10,000 km of the dwarf planet’s surface, and capture images at an unprecedented level of quality.

We’ll finally know what Pluto really looks like. And we’ll get a chance to see Pluto’s other moons at the same time.

Go here if you’d like a picture of Pluto.

Source: NASA

April 24, 2008December 24, 2015 by Fraser Cain

Pictures of Pluto

Pluto is so small and distant that we just don’t have any good pictures of it… yet. We get so many people asking that I’ve compiled together a gallery of the best pictures of Pluto. Some of these are actual Pluto pictures, captured by telescopes, while others are pics of Pluto done by an artist. Once NASA’s New Horizons spacecraft finally arrives in 2015, we’ll get some actual, close up images of Pluto and its moon Charon.

Even though Pluto’s not a planet any more, we can’t wait to see what it’s going to look like.

Each image links to a version you can use as your desktop background. To do this, click on an image to see the larger version, and then right-click and choose “Set as desktop”. Now you’ll have the picture as your background.

You can also look through these books from Amazon.com if you want more information about Pluto.

This is one of the best hubble pics of Pluto ever taken. It was photographed by the Hubble Space Telescope in 1994. The image clearly shows both Pluto and Charon as separate disks with surface features.

This is a picture of Pluto, captured by the Hubble Space Telescope. The photograph of Pluto was taken when the dwarf planet was 4.8 billion km (3 billion miles) from Earth. Hubble was able to see lighter and darker patches across the surface of Pluto. What’s happening here? We’ll have to wait for New Horizons to know better.

This is an artist’s illustration picture of Pluto and Charon seen from one of its smaller moons. Pluto is the large disk right in the middle of the photograph, and Charon is the smaller one over to the right. Pluto’s other tiny moon is the bright object to the left, just above the horizon. (Image credit: NASA).

Here’s a new portrait of the Solar System, with tiny Pluto and the other dwarf planets. You can see how they compare in size to the rest of the planets.

This is a picture of Pluto being visited by NASA’s New Horizons spacecraft. The actual encounter is going to happen in 2015, when the first close-up images of the surface of Pluto will be sent back to Earth.

I hope you enjoyed these Pluto pics.