Posted on by Fraser Cain

History of Planet Venus



Venus is one of the 5 planets visible to the unaided eye, and so it has been seen in the sky since prehistoric times. After the Sun and the Moon, Venus is the brightest object in the sky – brighter than any stars.

Venus is the Roman name for the Greek goddess of love; Aphrodite. But there are references to Venus as far back as Babylonian cuneiformic texts, like the Venus table of Ammisaduqa which could be as old as 1600 BC. Ancient Egyptians thought that Venus was actually two separate objects… a morning star, and then a completely different evening star. The tradition carried on with the ancient Greeks, as well.

The early mathematician Pythagoras was one of the first to recognize that the morning and evening stars were actually the same object: Venus. So perhaps he was the first to “discover Venus”.

The Maya civilization held Venus in high regard, and the planet figured prominently in their religious calendar.

Once he built his first rudimentary telescope, Galileo turned it towards Venus, was was astonished to find that the planet goes through phases like the Moon, going from crescent to gibbous to full and then back again. This was one of the strongest pieces of evidence that Venus goes around the Sun, and not the Earth as others originally believed.

Because Venus has always been obscured by thick clouds, science fiction writers have been free to imagine whatever they wanted existed on the surface of Venus. The clouds helped them to imagine a warm tropical world with constant rainfall and lush vegetation. The truth, of course, is that Venus is a hellish hot world, devoid of life.

Posted on by Tammy Plotner

Spock’s Astronomy Quiz

Leonard Nimoy as Mr. Spock. Credit: CBS Television

Have you ever wanted to test your astronomy knowledge against the best? Then take the warp speed jump to Spock’s Astro Quiz. It’s more than just astronomy trivia, it’s a great way to test your astronomy knowledge, learn more about astronomy related topics and interact via live chat with others interested in astronomy…

Welcome to Spock’s Astro Quiz, a great place to see just how much you know about astronomy and to enjoy the company of astronomy minded individuals. No special knowledge, secret passwords, or fancy hoops to jump through to enjoy the fun… All you have to do is click Log In and get started!

While you’re there, this interactive site will not only allow to test your astronomy skill against Spock’s, but to chat live with astronomy-minded visitors and play against each other as well. Just a word of caution though… Spock plays a clean astronomy game. Use a swear word and you’ll be warned once. Do it again and you’re permanently beamed out. The astronomy quiz and astronomy chat board is continually monitored and safe for players of all ages. Solicitors of any type will be immediately banned.

Test your astronomy skill… Enjoy the company of other astronomy friends during cloudy nights… And live long and prosper!

Brought to you by Macedon Ranges Observatory.

Posted on by Fraser Cain

Pictures of Planet Venus

Venus is one of the brightest objects in the night sky, so it’s not surprising that it’s been photographed many times. Some pictures of Venus have been taken from here on Earth, while other Venus pics have been taken from spacecraft orbiting the planet. You might be surprised to know that spacecraft have even landed on Venus (they didn’t last long), and took images of Venus from the surface.

Surface Image of Venus
This is a picture of Venus captured by NASA’s Magellan spacecraft. It shows the entire surface of the planet, imaged by the spacecraft’s radar instrument, which can penetrate the thick clouds to reveal the surface below. Magellan was launched from the cargo bay of the space shuttle Atlantis in May 1989, and arrived at Venus on August 10, 1990. It orbited the planet for 4 years before plunging to the surface.


3-D Image of Venus’ Surface
This is another photograph of Venus taken by NASA’s Magellan spacecraft. Planetary scientists used the radar data captured by Magellan to build up 3-dimensional images of the planet’s surface. This is an image of the Eistla Regio region, which contains volcanos and impact craters.



Photo of Venus from Pioneer Venus Spacecraft
This was one of the first ever close-up photographs of Venus, captured by NASA’s Pioneer Venus spacecraft. It’s actually a false color image made from ultraviolet images of the planet Venus by the spacecraft. The Pioneer Venus Orbiter went into orbit around Venus on December 4, 1978, and released several probes into Venus’ atmosphere to study it.


The Surface of Venus by Venera
You might be amazed to know that spacecraft have actually landed on the surface of Venus and sent pictures back. The Soviets sent a fleet of Venera spacecraft to Venus, and several actually made it down to the surface. Here’s a color photograph of Venus captured by the Venera 13 spacecraft, which landed on the surface of Venus on March 3, 1982.



Picture of Venus by Venus Express
This is a false-color image of Venus taken by the Venus Monitoring Camera on board ESA’s Venus Express spacecraft. It’s showing the planet’s southern hemisphere, including its south pole. The spacecraft captured the image when it was 35,000 km from the surface of Venus.

Posted on by Fraser Cain

Photos of the Earth and Moon – From Other Worlds

Image taken by the HiRISE camera on NASA's Mars Reconnaissance Orbiter, showing Earth and the Moon. Credit: NASA/JPL

We’re familiar with the close-up images of Earth captured by orbital satellites and astronauts on the International Space Station. But here are a few pictures of the Earth and Moon captured at a distance, while passing around the Moon, or orbiting distant Saturn. In the words of Carl Sagan, “Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.”

Since Sagan commented on Voyager 1’s image of Earth, several more pics of the Earth and Moon have been captured that really put our tiny spot in the Universe into perspective.


Voyager 1 – the Pale Blue Dot
This image, captured by NASA’s Voyager 1 spacecraft on February 14, 1990, is the one Sagan was talking about. It was taken when Voyager 1 was about 6.4 billion kilometres (4 billion miles) from Earth. In this image, the entirety of the planet takes up less than a single pixel; in fact, NASA calculated that we’re only 0.12 pixel in size. Sagan pushed the agency to capture images of all the planets in the Solar System, to create a family portrait seen from Voyager’s distant position.



Cassini – the Earth from Saturn
This is easily the best picture ever captured by NASA’s Cassini spacecraft, and in the running for the best space pictures of all time. It shows Saturn in all its glory, backlit by the Sun. From this view, the rings glow with an ethereal light.

But this image is extra special. Take a look towards the upper left of the image, and you’ll notice a tiny blue-white dot. Once again, there’s Earth, seen from a distance of 1.4 billion km (1 billion miles).


Mars Express – the Earth and Moon from Mars
ESA’s Mars Express captured this image of Earth and the Moon on July 3, 2005 when it was 8 million km (5 million miles). This was actually the first observational data sent back by the probe. A fitting introduction to Martian system. Of course, Mars Express was designed to image the relatively nearby surface of Mars, and not such distant objects, so the resolution of the image isn’t very good. And yet, they’re instantly recognizable as the Earth and Moon.

Opportunity Rover – the Earth from the Surface of Mars
Here’s an image of Earth captured from the surface of another planet. In this case, we’re seeing Earth from Mars, as photographed by NASA’s Mars rover Opportunity on April 29, 2005. Normally operating only in the Martian day, Opportunity woke up a little after sunset, and captured this image of Earth as the stars were starting to come out. The image of Earth looks a little elongated because it was moving slightly during the 15-second exposures. Imagine what some future Martian might see, stepping out onto the surface of the Red Planet in the dusky twilight to see our bright planet in the sky.


Rosetta – Earth and Moon during a flyby

Now this is what you might have been expecting to see. A picture of Earth, with the continents clearly visible. This photograph of Earth and the other of the Moon were taken by ESA’s Rosetta spacecraft during a flyby on November 15, 2007. Rosetta’s primary mission is to visit Comet 67P/Churyumov-Gerasimenko in May 2014, but this flyby was a great opportunity for Rosetta to test out its OSIRIS camera system. The image of the Moon was taken separately.


Earthrise – seen from the Moon
This is the classic “Earthrise” photograph, captured by astronaut William Anders during the historic Apollo 8 mission – the first human mission to the Moon. This photograph was taken on December 24, 1968. If you’re standing on the surface of the Moon, the Earth doesn’t actually “rise”. Since the Moon is tidally locked to the Earth, our planet always hangs in exactly the same point of the sky. It takes an orbiting spacecraft to see the Earth actually rise from the horizon.

This photograph was recreated by the Japanese Kaguya spacecraft, which captured a similar sequence of the Earth using its high-definition video camera.

Earth from Galileo
And finally, I think I’ve saved one of the best pictures for last. This is a photograph of the Earth and Moon (not to scale) captured by NASA’s Galileo spacecraft as it was speeding away towards Jupiter. Galileo captured these images in 1992, and finally reached the Jovian system in 1995-97. You’re looking at the Pacific Image, with South America visible as well as the Caribbean.

Posted on by Ian O'Neill

Lightning Storm Generated by Chilean Volcano (Images)

The Chaiten volcano erupting during storms in the middle of the night (Daily Mail - UK Newspaper)

It could be the scene from a movie: huge plumes of ash and gas rising during a ferocious volcanic eruption, sparking off a dazzling lightning storm; lightning bolts thundering to life inside and out of the hot cloud. However, this is the reality down on the ground for the people living near the Chaiten Volcano, southern Chile, who have been evacuated since the volcano erupted on Friday. Activity continues to increase, producing these terrifying, yet mesmerizing scenes…

Bolts of lightning erupt as the plume rises (Daily Mail/UPI/Carlos Gutierrez)

Lightning can happen as a result of a volcanic eruption. As the hot ash rises through the cooler atmosphere, transfer of charge occurs. This excess of electrons within the cloud makes it act like a capacitor, and should the conditions be correct, huge electrical discharges may be observed as bolts of lightning during volcanic eruptions. It seems that the Chaiten volcano’s recent activity has created the perfect conditions for such a show, allowing photographers in the region to capture some stunning images.

The eruption as viewed from orbit, probably from the ISS (Daily Mail)

I actually saw the picture shown at the top of this article in a double page spread in today’s edition of the UK’s Daily Mail. At first I couldn’t work out what I was seeing but on reading the caption I soon realized it was connected with the recent eruption in Chile. Fortunately the Daily Mail also posted the article on their website, giving me the opportunity to share these incredible images on the Universe Today.

The eruption looms (AP)

This region of South America has some very active plate tectonics and has been dubbed “Andean Arc” region of Chile, Peru, Ecuador and Columbia containing around 200 to 300 volcanoes. Volcanologists are highly concerned as many of these volcanoes are located in densely populated areas, so they are studying the Chaiten eruption very carefully. The small town of Chaiten is being threatened by this particular eruption, but fortunately the surrounding area is otherwise unpopulated.

Sources: Physorg.com, Daily Mail

Posted on by Nancy Atkinson

Snow on Mercury?

No, not that kind of snow, but scientists say deep inside the planet Mercury, iron “snow” forms and falls toward the center of the planet, much like snowflakes form in Earth’s atmosphere and fall to the ground. The movement of this iron snow could be responsible for Mercury’s mysterious magnetic field, and Mercury may be the only body in our solar system where this occurs.

Mercury and Earth are the only local terrestrial planets that possess a global magnetic field. But Mercury’s is about 100 times weaker than Earth’s, which scientists have been unable to explain.

Made mostly of iron, Mercury’s core is also thought to contain sulfur, which lowers the melting point of iron and plays an important role in producing the planet’s magnetic field.

To better understand the physical state of Mercury’s core, the researchers in a lab recreated the conditions believed to exist at Mercury’s core, and melted an iron-sulfur mixture at high pressures and high temperatures.

In each experiment, an iron-sulfur sample was compressed to a specific pressure and heated to a specific temperature. The sample was then quenched, cut in two, and analyzed with a scanning electron microscope and an electron probe microanalyzer.

As the molten, iron-sulfur mixture in the outer core slowly cools, iron atoms condense into cubic “flakes” that fall toward the planet’s center, said Bin Chen, University of Illinois graduate student and lead author of a paper published in the April issue of Geophysical Research Letters. As the iron snow sinks and the lighter, sulfur-rich liquid rises, convection currents are created that power the dynamo and produce the planet’s weak magnetic field.

The researchers say their findings provide a new context for the data that will be obtained from NASA’s MESSENGER spacecraft, which will flyby Mercury for a second time on October 6, 2008. It will pass by the planet again in September of 2009, and go into orbit in March of 2011.

Original News Source: Eureka Alert

Here are some interesting facts about Mercury.

Posted on by Nancy Atkinson

Where In The Universe? #4

Here’s this week’s “Where In The Universe?” mystery image. Your mission, should you choose to accept, is to guess what location in the universe is depicted here. No peeking below before you make a guess. Give yourself an extra point if you can name the feature shown here, and another point or two if you can name the spacecraft that took this image. I have to admit, I was drawn to this image strictly by the color: blue is my favorite, and especially this shade of blue. Kind of electric, don’t you think? Let’s see, could this be a moon, or a planet, or even a portion of a planetary nebula, or perhaps a photo from somewhere on our home planet? Make your guesses now, or maybe you knew what this was the moment you saw it….

Have you made your guess?

This spectacular image was taken by the Hubble Space Telescope. It’s a close-up view of an electric-blue aurora that is eerily glowing on the planet Jupiter. It was taken by HST’s Space Telescope Imaging Spectrograph (STIS) using an ultraviolet filter.

Auroras are curtains of light resulting from high-energy electrons racing along the planet’s magnetic field into the upper atmosphere. The electrons excite atmospheric gases, causing them to glow. The aurora is centered on Jupiter’s magnetic north pole.

Although this aurora resembles the same phenomenon seen at Earth’s polar regions, this image shows unique emissions from the magnetic “footprints” of three of Jupiter’s largest moons. These points are reached by following Jupiter’s magnetic field from each satellite down to the planet.

Auroral footprints can be seen in this image from Io (along the left hand limb), Ganymede (near the center), and Europa (just below and to the right of Ganymede’s auroral footprint). These emissions, produced by electric currents generated by the satellites, flow along Jupiter’s magnetic field, bouncing in and out of the upper atmosphere. They are unlike anything seen on Earth.

This ultraviolet image of Jupiter was taken with the on November 26, 1998. In this ultraviolet view, the aurora stands out clearly, but Jupiter’s cloud structure is masked by haze.

So, how’d you do?

Image credit: NASA/ESA, John Clarke (University of Michigan)

Link to image on the Hubble Site.

Posted on by Nancy Atkinson

JAXA Releases Boomerang Experiment Video

During the STS-123 mission to the International Space Station in March 2008 Japanese astronaut Takeo Doi tested a special boomerang in space to see how it worked in the microgravity environment of the ISS. The boomerang used in the experiment was a “Roomerang,” a small, tri-blade boomerang intended for use indoors in a small area or outdoors in light winds. IT was designed by boomerang expert Gary Broadbent, and it travels 5 to 8 feet before returning to the thrower.

The Japanese Space Agency has now released the video of the event:

As you can see, it worked very well, even in the small space of the ISS module. Broadbent told Universe Today that in the pressurized environment of the ISS, “microgravity has very little effect on the boomerang flight. The boomerang is so versatile, it can be tuned to fly in a perfect path back to the thrower, with gyroscopic precession and angular momentum over-compensating the lack of gravity.”

But Broadbent also said that a boomerang would not work in the vacuum of space. “You need air molecules to generate the lift to make the boomerang turn,” he said.

Here’s our earlier article about the boomerang experiment.

Original News Source: You Tube

Posted on by Ian O'Neill

NASA Considers Manned Asteroid Mission

Low gravity on an asteroid would be a big issue (NASA)

What would happen if we spot a Near-Earth Asteroid (NEO) heading straight for us? Assuming we had enough time, we might be able to pull together a group of brave astronauts (or oil drillers) and send them to the asteroid just in the nick of time to destroy it… oh hold on, that sounds like the storyline for a Hollywood blockbuster. Actually, NASA is planning a mission to an NEO, but not because it’s aimed at us. An asteroid named 2000SG344 (which threatened the Earth in the year 2000) is being considered as the destination for the first manned asteroid mission. The asteroid astronauts will travel there, chasing the 28,000 mi/hr (45,000 km/hr) speeding body and then carry out experiments, living on it for up to two weeks. Why? To briefly establish a manned outpost, advancing science and technology toward the ultimate goal: Mars.

The 1.1 million tonne asteroid was once thought to be a serious threat Earth. Back in 2000, there was a significant chance that asteroid 2000SG344 may have been on a collision course for Earth (with an explosive power of approximately 1 megatonne). Obviously it wasn’t, but it is expected to make an astronomically close flyby in 2030. Before then, NASA hopes to use this 40 meter-wide asteroid as the destination of a three to six month manned mission.

The asteroid mission would act as a “stepping stone” for future planetary missions to Mars and beyond. This three-month trek would provide vital technological, psychological and practical clues to what a manned deep space mission would face. Landing on an asteroid will be very difficult (due to the tiny influence of gravity on such a low-mass body), but it would provide an opportunity for astronauts to mine for water ice, use it for consumption and convert it into its component hydrogen and oxygen (for fuel and breathing). These tests would be essential before sending man on a long-term mission to Mars.

Under the current US administration, NASA has been instructed to send man back to the Moon by 2020. It is hoped that a more permanent base will be established soon after. Once the Moon base has been established, missions to Mars will become much easier to carry out. However, manned trips to near-Earth asteroids allow us to learn more about this potentially catastrophic hazard as well as developing deep space technology for the human presence on Mars.

In a study to be published in June, scientists at NASA’s Johnson Space Centre in Houston and Ames Research Centre in California will provide a rundown of their plans to use the future Orion spacecraft for this task, with a stop over of one- or two-weeks. I’m looking forward to seeing their recommendations for this ambitious development…

Source: The Guardian (UK)

Posted on by Ian O'Neill

Will Mars Astronauts be put in Suspended Animation for the Journey?

Sigourney Weaver in the film Alien (Brandywine Productions Ltd.)

Could you handle six months in space with a tiny handful of crew? Keep in mind you’d be doing everything with them, eating, sleeping, chatting, working, waiting, more sleeping, the occasional emergency, more chatting… If you look around your office now, could you really see yourself spending 24/7 with any of those guys for 24 weeks? Even the happiest, close-knit family would find it hard, especially at the close quarters they are likely to endure. Even if you had to spend that time with your partner, someone you love dearly, there would be stresses… after all you can’t exactly storm out of the spaceship and float home. You’re in it for the long-term.

The solution? Put the astronauts on their way to Mars into a suspended animation state. This not only saves the astronauts from potentially dangerous arguments, it would also save on food, air and water. So how can this be done? Hydrogen sulfide, the gas produced by rotten eggs, may be able to help…

Peggy Whitson, NASA astronaut, spent a record breaking six months on board the International Space Station (she returned on April 19th with a bit of a bump) and it appears she was able to make it through the days on board the ISS with her crew. However, the ISS had a very busy few months, plus it’s had several changes of crew and various new modules have been added. The ISS is a very different environment to work in than on board future missions to Mars. For starters, the main mission is to get to the Red Planet; the transit from Earth will be seen as the “run-up”. Although valuable science will undoubtedly be done, the accommodations are likely to be cramped and Mars astronauts will see the same faces day in and day out. Confrontations could become a serious problem. Supplying the ship with enough food and water for the trip will also be a difficult task. How can all these issues be faced? Put the astronauts in suspended animation.

Probably more familiar in science fiction movies (like the 1979 classic Alien, pictured top), suspended animation has some serious problems. Cooling the human body was thought to be the key to slowing the metabolism down sufficiently so space-bound crews could slip into hibernation for the duration of the long trip, but it seems this interferes with the rhythm of the heart. Now scientists at Harvard believe they have a solution.

Dr Warren Zapol, the head of anaesthesiology at Harvard University’s Massachusetts General Hospital, has been working on the effects that hydrogen sulfide has on the human body. More commonly known for the pungent smell produced by rotten eggs, hydrogen sulphide has been used on mice and the results have been very interesting. When breathed in, the gas slows mouse metabolism, but does not reduce the flow of blood to the brain and doesn’t interfere with the heart.

“The mice aren’t asleep. If you pinch their tails they respond. I don’t know what it’s like. Probably some slow-motion world.” – Dr Warren Zapol.

After about ten minutes of inhaling the gas, the mice slipped into a hibernation state. A reduction in oxygen consumption and carbon dioxide production was measured. This reduction continued for as long as hydrogen sulfide was administered and the test subjects recovered fully after normal air flow was supplied for 30 minutes. What’s more, oxygen levels in the blood did not vary, signifying that the major organs were not at risk of being oxygen starved. Mouse heart rate also dropped by 50%.

Of course many tests will be needed before hydrogen sulfide is administered to humans, let alone astronauts, but the preliminary results are encouraging. It looks like mice are joining the monkeys in mankind’s future on Mars…

Source:
ABC Science