Universe Today

August 2, 2007December 26, 2015 by Fraser Cain

Detailed Gravity Maps of the Earth will be Coming Soon

How high is Mount Everest? Really high? Nearly 9,000 metres? Come on, be precise. Don’t worry if you can’t, even geographers can’t agree. In 1999, the mountain’s height was stated as 8,850 metres, and then a Chinese survey in 2005 calculated it to be 8,844.43. That might not sound like much of a difference, but for scientists, it’s just too much uncertainty. Good thing a new spacecraft will be launching soon to settle the question once and for all.

ESA’s gravity field and steady-state Ocean Circulation Explorer (GOCE) is scheduled to blast off in early 2008. This sensitive satellite will then measure the Earth’s gravity field and geoid with unparalleled precision.

What’s the geoid? That’s a measure of the Earth’s gravity field at every point across the planet. Imagine you were able to extend the oceans across the surface of the entire planet, perhaps by cutting canals across the continents. This is how geographers can measure the height of a point above sea level, even when you’re thousands of kilometres away from the nearest ocean.

The geoid isn’t flat. Instead, it rises and falls depending on the local gravity at that exact point. If you’re traveling across the ocean on ship, you don’t stay at the exact same distance from the Earth’s centre point. Instead it varies, depending upon where on Earth you are. Pass by the Hawaiian islands, and their mass will draw the water up, raising sea level. Not a lot – the total variation is less than 200 metres, compared to a perfect mathematical ellipsoid. As you can imagine, the shape of this geoid is important to scientists.

When GOCE launches, it’ll fly at an altitude of 260 km. Instead of a traditional satellite, it’s streamlined, with fins that keep it stable as it passes through the last remnants of the Earth’s atmosphere. It will measure the Earth’s gravity to within an accuracy of 1-2 cm. In other words, they should be able to provide an answer to the Everest height question, once and for all. Not to mention, an accurate altitude for every other spot on Earth.

Here are some additional stories on measuring the Earth’s gravity, with GOCE and the previously launched GRACE satellite.

Original Source: ESA News Release

August 2, 2007December 26, 2015 by Fraser Cain

Engineers Working to Resolve Endeavour’s Air Leak

NASA workers are still working to fix the mysterious air leak in the space shuttle Endeavour’s cabin. They’ve been able to trace the problem down to one of two pressure-relief valves which are designed to ensure the crew cabin doesn’t become over-pressurized.

The space agency seems confident enough that they’ll trace down the source of the leak and have it resolved. The launch is still scheduled for Tuesday, August 7th at 7:02 pm EDT. If all goes well, Endeavour’s launch will begin mission STS-118 – the 22nd to fly to the International Space Station.

The shuttle has a collection of cargo, air, fuel and water on board, as well as another truss segment to build up the station’s backbone. I’ll keep you all posted if there’s another delay.

Original Source:NASA Space Shuttle

August 2, 2007December 26, 2015 by Fraser Cain

Astrosphere for August 2, 2007

New member Strongmanmike has joined the Bad Astronomy/Universe Today forum, and offers up this picture of Omega Centauri. Thanks, and welcome!

Now for the stories.

The Spaceward Foundation has opened up registration for their Light Racer Championship. In this race, drivers will compete with light-powered remote-control cars. Apart from being really fun, the technologies will help engineers work out the challenges of powering a vehicle with a beam of light.

There’s also a story over at Cnet.com about the space elevator challenges that’ll be happening at the event.

In the movie Sunshine, one of the characters goes out into the vacuum of space without a spacesuit. What would really happen to the human body? Slate magazine has the answers.

August 2, 2007December 26, 2015 by Fraser Cain

The Clear Skies Above Paranal

If you ever wondered why telescopes are perched atop the highest mountains, with the clearest skies, just check out this picture. That’s the night sky above the European Southern Observatory’s Very Large Telescope, located atop Paranal, a 2,600 metre (8,500 foot) mountain in Chile’s Atacama Desert. The photograph was taken by ESO astronomer Yuri Beletsky.

Here’s the cool thing. It’s a single image. The camera was tracking the stars, which is why they look so crisp, while the telescope domes look a little blurry.

The most striking part of the image is, of course, the wide band of stars in the Milky Way. It spans across 100 degrees of the sky. There are two brighter objects in the image as well. The larger, brighter object is Jupiter. You can make out that it has a planetary disk in the photograph. The other is the star Alpha Centauri (one of the closest stars to the Sun).

The beam stretching into the sky is part of the telescope’s adaptive optics system. It creates an artificial star in the sky above the observatory, which a sophisticated computer can use to calculate the amount of atmospheric distortion above the telescope. The telescope’s mirror is then distorted in real time to counteract the effects of the Earth’s atmosphere. It’s like having a space telescope without needing to actually head out into space.

Great picture Yuri!

Here are some past articles about adaptive optics system:

Original Source:ESO news Release

August 2, 2007December 26, 2015 by Fraser Cain

Planet Found Orbiting a Red Giant

About 5 billion years from now, our Sun will begin to run out of hydrogen, and swell up to become a red giant. The inner planets will be consumed, and the outer planets will have to deal with a much larger star. What will happen to the planets? We can’t know for sure, but a legendary team of planet hunters have discovered a planet orbiting another red giant.

A fateful look at things to come?

The discovery of a red giant star with a planet was made by Alex Wolszczan. If you don’t recognize the name, I’ll give you a little backgrounder. Wolszczan and his team were the first to discover planets orbiting another star – well, a pulsar actually, back in 1992. Subsequent observations have turned up entire solar systems of objects orbiting pulsars.

Alright, back to this discovery. Wolszczan and his team used the Hobby-Eberly Telescope – one of the largest and most powerful telecopes on Earth – to find a planet orbiting a red giant star. This star has approximately twice the mass of our own Sun, but it’s 10 times the size.

The planet orbits its star every 360 days, and was discovered using the Doppler shift technique. It was found because the pull of the planet’s gravity yanks its parent star back and forth. The change in this velocity is detectable by the Hobby-Eberly Telescope.

The discovery is important because it gives astronomers an idea of the fate that awaits our own Sun. Within 2 billion years, life on Earth will probably be unsustainable. And 5 billion years from now, our own Sun will become a red giant. As the star swells up, its changing density and gravity will disrupt the dynamics of the whole solar system. Planets will be pulled inward, and others will be flung out into space. Frozen moons orbiting giant planets like Jupiter might thaw out, and enter the star’s habitable zone for a brief period of time.

The more data astronomers can gather about this time, the better. And more data is coming. Wolszczan and his team have spent the last 3 years collecting data on over 300 stars, trying to identify ones which are good candidates for planets. So stay tuned.

Here are some previous stories on Wolszczan’s discoveries

And some stories on red giants:

Original Source:Penn State News Release

August 2, 2007January 24, 2021 by Fraser Cain

Carnival of Space #14

The carnival is back in town. Once again, I’m happy to host all manner of space blogs with the Carnival of Space. This gives you a chance to see how there’s a great big Universe of space writing out there. It’s a big group this week.

On the 38th anniversary of the first Moon landing, FlyingSinger recalled where he was on that day, how a supportive teacher had helped him get there, and how being there helped him to get into college and beyond. It’s really the story of how a young space nerd eventually became… a much older space nerd.

Astroblog has some stupid mobile phone tricks. Following “Animations of Venus”, made with low cost equipment, the ultimate low cost astrophotography, with a mobile phone camera. Amaze your friends!

After a terrible week for NASA, voices are again being raised accusing the space program of being too expensive and too dangerous, an extravagant luxury we can’t afford. This post on Cumbrian Sky looks at the recent events that have dominated the headlines, and concludes that despite setbacks like this, the “conquest of space” is ultimately inevitable, and something we should celebrate and support, not dismiss.

Phil for Humanity jumps into the debate whether people or robots should explore outer space. He gives a more detailed investigation into both sides of the argument.

Poor Pluto. As we near the one year anniversary of the IAU’s historic ‘re-definition-ing’ of the word planet, many people know that Pluto is no longer a planet, but a large majority of people don’t know why Pluto is not a planet. The common misconception is that Pluto itself was demoted, when in fact, the definition of the word ‘Planet’ was changed; and Pluto just did not fit the definition. Astroversity gives you an easy-to-follow explanation of why Pluto is no longer a planet.

The Moon is an ideal location for a variety of observations. A Babe in the Universe has an article about how a 2-meter multi-wavelength instrument could be placed on the Moon in a short time at a surprisingly low cost.

Advancednano discusses a variant of the nuclear thermal gaseous core rocket, which does not put any radiation into the atmosphere yet has 6.7 times the ISP of the space shuttle and can lift 40 times the cargo of the space shuttle.

Want to hunt comets and asteroids using images from the STEREO spacecraft? Astroblog gives you a handy guide to help you along, and an important note on the pesky problem of parallax.

Astropixie talks about the Martian blueberries, how they were formed, and their implications for water and life on Mars.

When astronauts get back to the Moon, it would be handy if they could pick up their oxygen locally. Spacefiles explains the ways you can extract oxygen from lunar regolith.

Emily Lakdawalla from the Planetary Society blog has an article about Saturn’s moon Helene. Voyager 2’s best view of Helene showed a blob a few pictures across. Cassini has been getting closer and closer to Dione’s co-orbital moon, and the most recent pictures showed a blocky world with sharp craters and mountainous ridges.

Selenian Boondocks has a brief overview of some recent research that suggests the our nearest neighbor might be a much more interesting place – both scientifically and economically – than previously imagined.

Centauri Dreams has an article called Galactic Drift and Mass Extinction. It looks at recent work on a possible cycle in mass extinction events on Earth that may be related to the Solar System’s position in the Milky Way.

Normally cynical, the Space Cynics are downright excited by the new 25 meter sub-millimeter telescope being built in Chile.

Before people can dream about mining asteroids, we are going to need to figure out how to land on them first – a problem that NASA and DigitalSpace may have already solved. Colony Worlds has the story.

Robot Guy has the space video of the week. This time, it’s the X-Prize winning flight of Scaled Composites’ SpaceShipOne.

Dr. Pamela Gay has all the details on a new study of 231 low metallicity stars in the local neighborhood points to past objects getting eaten by the Milky Way. As these stars pass though out area as the orbit in from the Halo, they let us learn about their past: where they came from and when they where eaten.

Phil Plait highlights some beautiful photographs of the Veil Nebula, captured by the Hubble Space Telescope.

And finally, for my own humble submission, I look forward through time, though the End of Everything.

August 1, 2007December 26, 2015 by Fraser Cain

Double the Hurricanes, Half the Fun

Researchers are reporting that the frequency of Atlantic hurricanes has doubled over the last century. 100 years ago, the Atlantic saw 6 severe storms a year, and now it experiences 15. The study concludes that warmer sea surface temperatures are to blame; changing wind patterns from global warming are fueling the increase in hurricanes.

This news comes from the most recent issue of the journal Philosophical Transactions of the Royal Society of London. The study is written by Greg Holland of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., and Peter Webster of Georgia Institute of Technology.

The researchers identified three periods since 1900, separated by sharp transitions, where the average number of hurricanes and tropical storms increased dramatically, and then remained at this new plateau. The first period was between 1900 and 1930, with 6 major storms a year. From 1930 to 1940, the number increased to 10. And then it increased again to an average of 15 from 1995 to 2005.

The increases in storm frequency and severity match the levels of warmer surface sea temperatures, which have risen over the last century. As temperatures rise, this has created warmer ocean temperatures, fueling the storms. The article authors note that the rise in Atlantic Ocean temperatures have been attributed to global warming in many other studies.

This study goes on to discuss what role natural storm cycles might have in the increase they measured. They found that natural cycles can’t be the entire cause because the increase has happened over the last century, and hasn’t been oscillating in tandem with a natural cycle.

2006 might have seemed like a slow year for storms. Maybe today. But 100 years ago, it would have seemed normal, or even above average compared to average storm frequency.

Original Source: NSF News Release

August 1, 2007December 26, 2015 by Fraser Cain

Networking Across the Planets

I don’t know about your Internet connection, but I have enough trouble wiring up my home network. Imagine trying to connect together spacecraft orbiting millions of kilometres away into a serviceable network. That’s just what’s going to happen when NASA’s Phoenix Lander arrives at the Red Planet. In the spirit of cooperation, ESA’s Mars Express will be on hand to watch the Phoenix lander during its entry and landing phases of the mission.

If everything goes well, Phoenix will blast off from Cape Canaveral on August 4th, making its way to the Red Planet atop a Boeing Delta II rocket. It’ll then take several months to reach Mars, arriving in spring, 2008.

For missions to Mars, the most dangerous moment is the Entry Descent and Landing (EDL) phase, where the spacecraft plunges through the thin Martian atmosphere. Go too fast and you crash into the planet; too slow and you just skip off the atmosphere, and head off into space. For more information about why this is hard, check out this article.

With such a dangerous maneuver, it’s good to know there’ll be another set of eyes watching overhead. Mars Express will optimize its orbit over the next few months so that it’ll be keeping Phoenix directly in sight for the entire EDL phase. Mars Express is equipped with a special electronics package designed to communicate with landers on the surface of Mars. It was originally designed to communicate with Beagle 2, but it’ll be repurposed to talk to Phoenix.

If all goes well, Mars Express will receive regular updates from Phoenix through the decent and landing stages, and then over the lander’s anticipated 90-day lifespan. Let’s hope everything goes well, but if things go poorly, the spacecraft will be able to give mission controllers detailed information about how the lander went splat, so they can work out why. If only Beagle 2 had been so lucky.

Original Source:ESA News Release

August 1, 2007December 26, 2015 by Fraser Cain

Another Reminder, Go See the Perseids

My favourite meteor show is less than 2 weeks away now, so I wanted to give you all another gentle reminder to get organized and make sure that you’re able to enjoy the Perseid meteors this year – the shower will be peaking on the night of August 12, and into the next morning. It’s going to be a special event because the shower coincides with a new moon. The sky will be at its darkest, and the meteors will be at their brightest.

The shower gets its name because they will appear to originate from the constellation of Perseus. Don’t worry about finding the constellation, though, just lay on your back and stare up, you’ll see them.

On the evening of August 12, the first thing you’ll want to do is head outside shortly after sunset. If you’re lucky, you’ll see “earthgrazers”. These are some of the most beautiful meteors that you’ll see in the whole evening. Then settle down, find some satellites, and wait for the show to really get going. It you’ve got the stamina, the best viewing will happen in the early dawn hours of Monday, August 13th. At that point, you could be seeing a few dozen every hour.

To really get the best experience out of this, travel away from the lights of the city. Here in Vancouver, we need to get about 50 km away to start seeing the Milky Way above our heads. We’ve got a dark sky park in a suburb called Abbotsford that’s perfect.

So get organized. Book the evening with your friends, map out where you’re going to go. Bring hot drinks, warm clothes, and a comfortable place to sit back and enjoy the show.

And if you’re interested, Pamela and I recorded an episode of Astronomy Cast dealing with meteors and meteor showers, so you can listen in the car before you reach your viewing spot.

Enjoy, and let me know how it goes.

August 1, 2007December 26, 2015 by Fraser Cain

Poor Weather Might Take out Opportunity

Okay, this is starting to get worrysome. As I reported twice in the past few weeks, there’s a series of dust storms currently raging across the surface of Mars. And the plucky Mars rovers, Spirit and Opportunity are right in the middle of it. NASA put out a news release today, that was a little grim.

They’re worried about Opportunity.

As you know, the Mars Exploration Rovers are solar powered. Every activity they take: driving around, using their instruments, and communicating with Earth requires electricity generated through solar power. The power isn’t an option, it’s a necessity. That’s because they use the energy to run a heater that keeps their most fragile equipment warmed during the frigid Martian nights.

The latest communications received from Opportunity on July 30, 2007 told a grim tale. Dust from the atmosphere is settling out onto the rovers’ solar panels, blocking the amount of light they receive. The rover is already in a low-power regimen, using the absolutely bare minimum to survive. And the light it’s receiving is steadily going down.

Even though the weather has gotten a little warmer since the dust storm started, the temperature of Opportunity’s electronic modules has gone down at night. Right now, it’s getting down to -37 degrees C (-35 degrees F). This is just within a couple of degrees from the point that the rover will need to turn on its electronics heaters. At that point, the heaters will deplete the rover’s batteries more quickly than it can refill them with sunlight.

NASA engineers have a plan, but it’s a little bit risky. They’re having the rover use its electronics for a longer period each day. If the skies don’t clear up, it might go overboard and switch into a low-power fault mode. This would take the batteries off-line, and put the rover to sleep to wait for sunlight to return. The rover might go to sleep for days, weeks or even months, waiting for enough sunlight to get moving again.

“We will continue to watch the situation on Mars and do all we can to assist our rovers in this ongoing battle against the environmental elements on the Red Planet,” said John Callas, rover project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Original Source: NASA/JPL News Release