Where In The Universe Challenge — With a New Twist

Here’s the image for this week’s “Where In The Universe” challenge. But we’re going to try something different this time. Several readers have suggested (and maybe even begged) that we don’t reveal the answer right away, but allow everyone a chance to mull over the image and provide their answer in the comment section. Then tomorrow, I’ll post the answer and you can see how you did. So here you go: Take a look at the image above and try to determine where in the universe this image was taken. Give yourself extra points if you can name the spacecraft responsible for taking this image. Post your answers in the comments (if you’re brave enough!) and check back tomorrow for the answer. Good luck!

The Violent Variations of Black Holes

Artist impression of a black hole. Credit: ESO/L. Calçada

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What is the environment around a black hole really like? Astronomers are getting a better idea by observing the light coming from the accretion disk surrounding black holes. The light is not constant — it flares, sputters and sparkles – and this flickering provides new and surprising insights into the colossal amount of energy emanating from around black holes. By mapping out how well the variations in visible light match those in X-rays on very short timescales, astronomers have shown that magnetic fields must play a crucial role in the way black holes swallow matter.

“The rapid flickering of light from a black hole is most commonly observed at X-ray wavelengths,” says Poshak Gandhi, who led the international team that reports these results. “This new study is one of only a handful to date that also explore the fast variations in visible light, and, most importantly how these fluctuations relate to those in X-rays.”

The observations tracked the flickering of the black holes simultaneously using two different instruments, one on the ground and one in space. The X-ray data were taken using NASA’s Rossi X-ray Timing Explorer satellite. The visible light was collected with the high speed camera ULTRACAM, a visiting instrument at ESO’s Very Large Telescope (VLT), recording up to 20 images a second. ULTRACAM was developed by team members Vik Dhillon and Tom Marsh. “These are among the fastest observations of a black hole ever obtained with a large optical telescope,” says Dhillon.

To their surprise, astronomers discovered that the brightness fluctuations in the visible light were even more rapid than those seen in X-rays. In addition, the visible-light and X-ray variations were found not to be simultaneous, but to follow a repeated and remarkable pattern: just before an X-ray flare the visible light dims, and then surges to a bright flash for a tiny fraction of a second before rapidly decreasing again.

Watch a movie of the fluctuations.

None of this radiation emerges directly from the black hole, but from the intense energy flows of electrically charged matter in its vicinity. The environment of a black hole is constantly being reshaped by a competing forces such as gravity, magnetism and explosive pressure. As a result, light emitted by the hot flows of matter varies in brightness in a muddled and haphazard way. “But the pattern found in this new study possesses a stable structure that stands out amidst an otherwise chaotic variability, and so, it can yield vital clues about the dominant underlying physical processes in action,” says team member Andy Fabian.

The visible-light emission from the neighborhoods of black holes was widely thought to be a secondary effect, with a primary X-ray outburst illuminating the surrounding gas that subsequently shone in the visible range. But if this were so, any visible-light variations would lag behind the X-ray variability, and would be much slower to peak and fade away. “The rapid visible-light flickering now discovered immediately rules out this scenario for both systems studied,” asserts Gandhi. “Instead the variations in the X-ray and visible light output must have some common origin, and one very close to the black hole itself.”

Strong magnetic fields represent the best candidate for the dominant physical process. Acting as a reservoir, they can soak up the energy released close to the black hole, storing it until it can be discharged either as hot (multi-million degree) X-ray emitting plasma, or as streams of charged particles travelling at close to the speed of light. The division of energy into these two components can result in the characteristic pattern of X-ray and visible-light variability.

Papers on this research: Here and Here

Source: ESO

18-Year-Old Rocket Motor Found in Australian Outback

A solid rocket motor casing from a commercial U.S. Delta 2 launch vehicle was found inAustralia, nearly 18 years after it reentered. Picture by Michael White

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This just in from ‘The Sky is Falling’ Department: NASA’s Orbital Debris Newsletter reports that a launch vehicle rocket motor casing was found by ranchers in the Australian Outback during a cattle round-up on a three million-acre pasture property. It was first spotted by Mr. Arthur Taylor who was flying a Cessna aircraft to look for stray cattle. The casing appeared in relatively good condition (see picture above) and did not seem to be very old. Mr. Michael White forwarded numerous photos of the object to the NASA Orbital Debris Program Office, including one with a clear serial number next to the nozzle attachment point. Using the serial number, NASA Kennedy Space Center personnel were able to trace the motor casing to a a specific mission.

The casing came from a Delta 2 rocket used on June 2, 1990 to launch the Indian INSAT-1D geosynchronous spacecraft from the Cape Canaveral Air Force Station, Florida. This solid rocket motor served as the launch vehicle’s third stage which carried the payload from a low altitude parking orbit into a geosynchronous transfer orbit. (If you want to trace it yourself, here are the particulars: U.S. Satellite Number 20645, International Designator 1990-051C), Reentry of the stage occurred a few months later.

This isn’t the first time rocket casings have been found in Australia, and this object joins similar solid rocket motor casings found in Saudi Arabia, Thailand, and Argentina during the past several years.

Yikes!

Sources: CollectSpace, NASA’s Orbital Debris Program

Space Tourist Garriott Docks with Station (Videos)

The Soyuz TMA-13 approaches the Space Station alongside another Soyuz spaceship, set to return Garriott in 10 days (NASA)

[/caption]The Soyuz TMA-13 carrying Expedition 18 to the International Space Station (ISS) has successfully docked, delivering astronaut Mike Fincke, cosmonaut Yuri Lonchakov and space tourist Richard Garriott. The Soyuz spaceship docked with the Zarya module ahead of schedule over breathtaking views of southern Asia. Richard Garriott, a 47 year-old computer games entrepreneur and son of retired US astronaut Owen Garriott, spent $30 million for the privilege of spending ten days travelling to, and living on the orbital outpost. To appreciate how the Earth has changed in the 35 years since his father first looked down on Earth from the US Skylab space station, Garriott Jr. will spend some of his time taking photos of our planet so the images can be compared…

It looked like a flawless docking procedure between the Soyuz spacecraft and the ISS over the scenic backdrop of the Earth. Soyuz gently floated toward its dock with the Russian-built Zarya module along side the Soyuz TMA-12 that carried Expedition 17 to the station back in April. The already parked Soyuz will be the return vehicle in eight days time (on October 23rd) for cosmonauts Sergei Volkov and Oleg Kononenko who will chaperone Richard Garriott back to solid ground at the end of his space “vacation.” Volkov and Kononenko, members of Expedition 17 have spent six months in space.

View the Soyuz TMA-13 dock with the space station »

'Running the lockers' inside Skylab. (NASA)
'Running the lockers' inside Skylab. (NASA)
Now that Garriott is getting settled in his temporary orbital home, he only has a short time to complete all the tasks he has set. As the sixth space tourist to visit the space station, he will obviously enjoy the views, but Garriott is also keen to follow in his father’s footsteps. Owen Garriott lived and worked on Skylab in 1973 for 59 days and he found that by running around the circumference of the station, that he was able to build up enough centrifugal force to remain in contact with the sides. Although Garriott Jr. is keen to try this zero-gravity activity out for himself, the International Space Station doesn’t have a large enough volume.

I have been trying to figure out where on the International Space Station could this best be performed,” Richard said. “One of the great things about Skylab is that it had this massive internal volume and this nice ring of lockers that gave you a relatively smooth surface to make that attempt and a reasonable diameter so that at a nice jog pace, the centrifugal force would do a reasonable job of holding you to the outside wall. The ISS’s diameter is much smaller.” So it would appear that “running the lockers” as Owen called it, will not be possible on board the ISS. I guess they don’t make space stations like they used to

View the Expedition 18 crew arrive on the space station, being welcomed by Sergei Volkov and Oleg Kononenko »

Jogging inside the space station to one side, the Expedition 18 crew will begin to supervise the start-up of new life-support equipment for the station. This is one of the steps to ensure that the station can accommodate six full-time crewmembers as from the planned expansion in May 2009.

Sources: BBC [1] [2], collectSPACE

Martian Dust Storm Hampers Phoenix Lander’s Activities

Dust storm on Mars. Credit: MARCI Science Team

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The science team for the Phoenix Lander was forced to curtail many of their activities over the weekend because of a regional dust storm that temporarily lowered the lander’s solar power. But Phoenix weathered the storm well, and the team is back investigating the Red Planet’s northern plains. The 37,000 square-kilometer storm (nearly 23,000 miles) moved west to east, and weakened considerably by the time it reached the lander on Saturday, Oct. 11. The science team was expecting the worst, so this tamer storm put the spacecraft in a better than expected situation, said Ray Arvidson of Washington University in St. Louis, the lead scientist for Phoenix’s Robotic Arm.

The lander is now back to busily collecting samples and weather data, analyzing the soil samples, and conducting other activities before fall and winter stop Phoenix cold.

“Energy is becoming an issue, so we have to carefully budget our activities,” Arvidson said.

The Phoenix team tracked the dust storm last week through images provided by the Mars Reconnaissance Orbiter’s Mars Color Imager. The imager’s team estimated that after the dust storm passed through Phoenix’s landing site on Saturday, the dust would gradually decrease this week.

This dust storm is a harbinger of more wintry and volatile weather to come. As Martian late summer turns into fall, the Phoenix team anticipates more dust storms, frost in trenches, and water-ice clouds. They look forward to collecting data and documenting this “most interesting season,” Arvidson said.

Source: Phoenix News Site

Procedure to Repair Hubble Begins Wednesday

The Hubble Space Telescope. Credit: NASA

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The procedure to begin “brain surgery” on the Hubble Space Telescope will begin at 6:00 am EDT (10:00 GMT) on October 15. The venerable space telescope will be put into electronic hibernation; then engineering teams will work from the ground around the clock for two days to reconfigure a data handler system which failed two weeks ago. If the procedure is successful, science operations could resume as early as Friday, October 17. The Control Unit/Science Data Formatter, which relays science data to Earth, is a redundant system, with two sides. Side A has been used exclusively since the telescope’s launch over 18 years ago in 1990. Side B hasn’t been powered on since well before launch. “It is obviously a possibility that things will not come up,” said Art Whipple, manager of the Hubble Space Telescope Systems Management office at the Goddard Spaceflight Center in Greenbelt, Md. “We have very good confidence this will work. In addition, we have contingency plans built in at each step of the transition where if something does not go the way we expect it to, we’ll be able to back out and go down an alternate path.”

Whipple said there is very little aging that goes on with an unpowered component in space. “It’s actually a very benign storage environment,” he said.

In addition six associated components have to be switched over to a redundant side as well. “Five of the six redundant components in this data management system that will be brought on line have also not been powered since 1990,” said Whipple. “The command procedures to accomplish this transition have been thoroughly tested.”

Engineers and mission managers have been working the past two weeks, devising a plan and testing procedures. NASA headquarters gave approval for the activation on Tuesday.

The planned Hubble Servicing Mission 4, shuttle mission STS-125, would have launched today (Oct. 14) if the data handler had not gone off line. NASA has re-set a tentative launch date for mid-February. The seven member crew, commanded by veteran Scott Altman, will perform five back-to-back spacewalks to add new cameras, (the Wide Field Camera 3 (WFC3) and the Cosmic Origins Spectrograph), replace old batteries and gyroscopes, add docking equipment and upgrade the telescope’s guidance system. The astronauts will also attempt to fix the Space Telescope Imaging Spectrograph (STIS) and the Advanced Camera for Surveys (ACS). Those two were never designed to be repaired in orbit. In addition, a spare data handler system will brought up, after engineers test and certify the unit. That unit has not been turned on since 1992.

It has yet to be determined if the spare data handler will be ready by mid-February, and if the astronauts can be trained ready for the additional work required for the unit switch-out.

“We think in the first week or two in November we will have a much better handle on the actual state of the hardware,” Whipple said. “The paperwork says February should be supportable, but we should have much higher confidence (in November).”

Sources: NASA press release, NASA news conference

Mass of the Moon

NASA's image of the Moon

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The mass of the Moon is 7.347 x 1022 kg.

That sounds like a large number, and I suppose it is compared to the mass of a single person, a car or even a building. But you’ve got to keep it in context. The mass of the Moon is only 1.2% the mass of the Earth. In other words, you would need 81 objects with the mass of the Moon to match the mass of the Earth.

The diameter of the Moon is only about 1/4 the diameter of the Earth, so it might seem like the mass of the Moon is strangely low. And you would be right. The key is the Moon’s low density. It has a density of only 3.3 g/cm3. This is almost half the density of Earth.

Astronomers think that a Mars-sized object crashed into the Earth about 100 million years after the Earth formed. The huge cloud of ejected debris coalesced into the Moon, which still orbits us today. The Moon has a lower density because the impact gouged out the outer crust and mantle, and didn’t eject so much of the Earth’s iron core.

Want more information about the mass of the Earth? Or what about the mass of Mars?

The Physics Factbook has more information about the mass of the Moon. And here’s an article that explains how you would go about weighing the Moon.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Reference:
NASA Moon Facts

Lunar Day

Earthrise. Image credit: NASA

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A lunar day is the length of time it takes for the Moon to make one complete rotation on its axis compared to the Sun. This is important because the Moon is tidally locked with respect to the Earth. So it always points the same face towards the Earth as it goes around the planet. So, how long is a day on the Moon?

The lunar day lasts 29 days, 12 hours and 44 minutes. And this the same time it takes for the Moon to orbit around the Earth.

With respect to the background stars, however, the Moon only takes 27 days and 7 hours for the sky to completely rotate back to its original position.

So why is there a difference?

As the Earth and Moon are orbiting around the Sun, they complete a circle over the course of the year. Each time the Moon goes around the Earth, it needs to go a little further to get the Sun back into the same position.

If you ever get the opportunity to stand on the surface of the Moon, and look at the Earth, our planet would always remain in the exact same position in the sky. The Sun, on the other hand, will still rise, move across the sky and then set. Of course, an average day will last 29 days, 12 hours and 44 minutes until the Sun returns to the same position in the sky.

Astronomers say that the Moon is tidally locked to the Earth. At some point in the distant past, the Moon rotated more rapidly than it currently does. The Earth’s gravity caused part of the Moon to bulge out. The pull of gravity caused the rotation of the Moon to slow down until this bulge was pointing directly at the Earth. At this point, the Moon was tidally locked to the Earth; this is why it shows the same face to us.

And it’s also why a lunar day lasts the same as it takes the Moon to go around the Earth.

One of the most famous pictures taken during the space age is Earthrise, captured by the Apollo 8 astronauts. Here’s an article about it, and here’s an update from the Japanese Kaguya spacecraft.

Here’s an animation from NOAA showing how the Moon’s position affects the tides. And have you ever wondered why you can see the Moon during the day?

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Gravity on the Moon

A NASA astronaut on the lunar surface (credit: NASA)

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Are you feeling heavy? Maybe it’s time to go to the Moon, where you’ll experience much less gravity. Since the Moon is smaller, and has much less mass, it pulls with less gravity. In fact, if you could stand on the surface of the Moon, you would experience only 17% the force of gravity that you would experience on Earth. Gravity on the Moon is much less.

Just to give you an example, let’s say that you weighed 100 kg on Earth. If you stood on the Moon, and then onto your bathroom scale your weight would only be 17 kg. With gravity on the Moon so low, you would be able to jump much higher. If you can jump 30 cm on Earth, you would be able to jump almost 2 meters straight up into the air. And you would be able to fall much further on the Moon. If you jumped off the roof of your house, it would only feel like you jumped off a table. You would be able to throw a ball 6 times further, hit a golf ball 6 times further… you get the idea.

When the Apollo astronauts first walked on the surface of the Moon, they needed to learn how to walk differently in the Moon’s gravity. That’s why the astronauts do a funny hopping run as they move across the surface of the Moon. If they tried to take normal steps, they would fly up into the air to far and fall over – that did happen a few times.

One last, fascinating idea. The pull of gravity on the Moon is so low that you could actually fly with wings attached to your arms (as long as you were inside an enclosed dome filled with air at the Earth’s atmospheric pressure. Wouldn’t it be great to be able to fly around like a bird?

Do you wonder about the gravity of Mars, or the gravity of Jupiter?

There are some cool calculators out there that let you take your weight and see what you would experience on other planets. Check this one out.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Double Moon

Mars. Credit: NASA

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Have you ever heard that there’s a special time of the year when you’ll be able to see Mars in the sky so big that it looks like a double Moon? You might have gotten this as an email from a friend or family member. Here’s an example of the email.

The Red Planet is about to be spectacular! This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history. The next time Mars may come this close is in 2287. Due to the way Jupiter’s gravity tugs on Mars and perturbs its orbit, astronomers can only be certain that Mars has not come this close to Earth in the Last 5,000 years, but it may be as long as 60,000 years before it happens again.

The encounter will culminate on August 27th when Mars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide. At a modest 75-power magnification

Mars will look as large as the full moon to the naked eye. By the end of August when the two planets are closest, Mars will rise at nightfall and reach its highest point in the sky at 12:30 a.m. That’s pretty convenient to see something that no human being has seen in recorded history. So, mark your calendar at the beginning of August to see Mars grow progressively brighter and brighter throughout the month. Share this with your children and grandchildren. NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN

Are we going to get a chance to see a double Moon? I’m sorry, but this is a complete hoax and Internet myth. We’ve written many times about this on Universe Today. Here’s a link to a more complete article.

Each time this email hoax goes around the Internet, it doesn’t mention the year. It only says August 27th, but it doesn’t say what year. In reality, this email first started in 2003. But because the email doesn’t have a year, it keeps coming around year after year. There wasn’t a double moon back in 2003. And there won’t be one this year – whenever you’re reading this.

Mars did make a close approach back in 2003, but it was only slightly closer than it gets any other year that it makes a close approach to the Earth. It came within 34.6 million km. But if you don’t understand how far away that is, it’s hard to see that it can’t be anywhere near as close or big as the Moon. Mars looked like a bright red star in the sky. But nothing like a double moon.

What this email is trying to say is that if you put your eye to the telescope and looked at Mars at 75 power magnification, it would look about the same size as the Moon looks with the unaided eye. In other words, you’d see a double moon if you could somehow look at both at the same time – but you can’t.

I hope this helps clear up the double moon myth.

We’ve tackled this myth many times in the past. Here’s the one we did in 2006, 2007, and 2008.

Maybe you’re looking for the Double Moon music company?

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Reference:
NASA: Beware the Mars Hoax