Really Rocket Science - Astronomy

DIY Friday: Sky Show

Fri, 04 Jul 2008 04:56:41 -0700

No, not your own fireworks -- playing with chemistry at home is dangerous. We're talking dazzling astronomic observation, as this "image of the day" from NASA:

Stars and a Stripe in Celestial Fireworks

A delicate ribbon of gas floats eerily in our galaxy. A contrail from an alien spaceship? A jet from a black-hole? Actually this image, taken by NASA's Hubble Space Telescope, is a very thin section of a supernova remnant caused by a stellar explosion that occurred more than 1,000 years ago.

Around May 1, 1006 A.D., observers from Africa to Europe to the Far East witnessed and recorded the arrival of light from what is now called SN 1006, a tremendous supernova explosion caused by the final death throes of a white dwarf star nearly 7,000 light-years away. The supernova was probably the brightest star ever seen by humans, and surpassed Venus as the brightest object in the night time sky, only to be surpassed by the moon. It was visible even during the day for weeks, and remained visible to the naked eye for at least two and a half years before fading away.

It wasn't until the mid-1960s that radio astronomers first detected a nearly circular ring of material at the recorded position of the supernova. The ring was almost 30 arcminutes across, the same angular diameter as the full moon. The size of the remnant implied that the blast wave from the supernova had expanded at nearly 20 million miles per hour over the nearly 1,000 years since the explosion occurred.

Today, SN 1006 has a diameter of nearly 60 light-years, and it is still expanding at roughly 6 million miles per hour. Even at this tremendous speed, however, it takes observations typically separated by years to see significant outward motion of the shock wave against the grid of background stars. In the Hubble image as displayed, the supernova would have occurred far off the lower right corner of the image, and the motion would be toward the upper left.

Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

But NASA is predicting a planetary alignment for today and this weekend, via PhysOrg.com:

The show gets going on Friday, July 4th. Red Mars and ringed Saturn converge just to the left of the bright star Regulus. The three lights make a pretty 1st-magnitude line in the heavens.

But that is just the beginning. On Saturday, July 5th, with weekend fireworks at fever pitch, a lovely crescent Moon joins the show. Saturn, Mars, and the Moon trace an even brighter line than the night before.

Scan a small telescope along the line. You'll see Saturn's rings, the little red disk of Mars, a grand sweep of lunar mountains and craters, and just maybe—flash!—a manmade incendiary. How often do you see fireworks through a telescope?

This is, however, more than just a flashy gathering of planets—it is also a gathering of spaceships and robots.

Each of the three worlds is orbited or inhabited by probes from Earth. Saturn has the Cassini spacecraft, studying the gas giant's storms, moons and rings. The Moon has two probes in orbit: Kaguya from Japan and Chang'e-1 from China. The pair, operating independently, are mapping the Moon and scanning for resources in advance of future human landings. NASA's Lunar Reconnaissance Orbiter will join them later this year.

Mars has more probes than the others combined. Three active satellites orbit the red planet: Europe's Mars Express and NASA's Mars Odyssey and Mars Reconnaissance Orbiter. The three not only study Mars with their own instruments, but also form a satellite network in support of NASA's Mars rovers Spirit and Opportunity and Mars lander Phoenix.

None of these mechanical specks are visible in a backyard telescope, but they are there, heralds of a growing human presence in the solar system. Tell that to your buddy at the fireworks show!

During the short night of July 5th, the Moon glides past Mars and Saturn so that nightfall on Sunday, July 6th, brings a different arrangement—a scalene triangle. The triad is easy to find in the hours after sunset. Look west and let the Moon be your guide.

In the nights that follow, the Moon exits stage left, leaving the others behind. Don't stop watching, though. Saturn and Mars are converging for their closest encounter of the next 14 years. After nightfall on Thursday, July 10th, the two planets will be just ¾ of a degree apart, snug enough to fit behind the tip of your pinky finger held at arm's length.

Now that's spectacular—no fireworks required.

Cool. No smoke, fire or noise. There's more than enough of that going on around you. To all the rocket scientist in the U.S., have a great 4th of July.

Super-Earths Galore!

Mon, 16 Jun 2008 09:32:15 -0700

Just how common are Earth-like planets in the universe?

About five times more common than previously thought, according to European researchers presenting their latest findings at a conference in France today:

European astronomers on Monday said they had located dozens of giant planets in three distant solar systems.

The discovery suggests that at least one third of stars similar to our own Sun harbour such planets, multiplying previous estimates by five.

A trio of these 'super-Earths' -- so-called because they are several times the mass of our own planet -- were detected orbiting a star known as HD 40307 some 42 lights away.

Reuters has additional details:

The [three] planets are bigger than Earth -- one is 4.2 times the mass, one is 6.7 times and the third is 9.4 times.

They orbit their star at extremely rapid speeds -- one whizzing around in just four days, compared with Earth's 365 days, one taking 10 days and the slowest taking 20 days.

The first planet outside our solar system was detected in 1995, and less than 280 of these exoplanets had been found before today's unveiling of 45 new exoplanet discoveries.

The astronomers used the High Accuracy Radial velocity Planet Searcher-- or HARPS -- to spot the planets. The next-generation HARPS spectrograph is used in conjunction with the 3.6-m telescope at La Silla observatory in Chile:

La Silla is a 2400-m mountain, bordering the southern extremity of the Atacama desert in Chile. It is located about 160 Km north of La Serena. Its geographical coordinates are: Latitude 29º 15' south & Longitude 70º 44' west.

Originally known as Cinchado, the mountain was renamed La Silla (the saddle) after its shape. It rises quite isolated and remote from any artificial light and dust sources (astronomy's worst enemies). La Silla was the first ESO observatory built in Chile.

The ESO press release also has additional information on these exciting, extra-solar discoveries.

Technorati Tags: astronomy science space solar+system exoplanets planets HARPS

Mars Madness is Building

Thu, 15 May 2008 08:08:37 -0700

Mars Madness is on the rise in Tucson, the Arizona Daily Star reports. That's because on May 25th, NASA's Phoenix Mars Lander is scheduled to touch down on the red planet. The event is significant in Tucson because the University of Arizona's Lunar and Planetary Lab team is leading the mission's science and built some of the instruments.

But the fever is spreading well beyond Arizona for this risky mission:

Fewer than half of attempts to land on Mars have succeeded, but planetary scientists leading the Phoenix Mars mission are cautiously optimistic. So far, all looks good, they say.
Public events to celebrate the landing are planned for at least 110 sites around the world, including London and Paris. There's even a virtual landing bash planned, in Second Life, which is a virtual social world on the Internet.

Just how risky and difficult is it to put a lander on the surface of Mars? To answer that question, check out this excellent video from NASA's Jet Propulsion laboratory. (NASA has done a fantastic job promoting the mission and landing in the style of a summer movie blockbuster):

The Phoenix Mars Mission website provides additional detail:

At 125 km (78 miles) above the surface, Phoenix will enter the thin martian atmosphere. It will slow itself down by using friction. A heat shield will protect the lander from the extreme temperatures generated during entry. Antennas located on the back of the shell which encases the lander will be used to communicate with one of three spacecraft currently orbiting Mars. These orbiters will then relay signals and landing info to Earth.

After the lander has decelerated to Mach 1.7 (1.7 times the speed of sound), the parachute is deployed. Shortly after the parachute is deployed, the heat shield is jettisoned, the landing radar is activated, and the lander legs are extended. The lander continues through the Martian atmosphere until it comes within 1 km (.6 miles) of the Martian surface. At this point, the lander separates itself from the parachute. It then throttles up its landing thrusters and decelerates.

When Phoenix is either at an altitude of 12 m (39 ft) or traveling at 2.4 m/s (7.9 ft/s), the spacecraft begins traveling at a constant velocity. The landing engines are turned off when sensors located on the footpads of the lander detect touchdown.

As we've mentioned, only half of all international attempts to land on Mars have succeeded. Back in 1999, the Mars Polar Lander (MPL) went missing as it entered Mars’s atmosphere, and its fate has been a mystery ever since. But now there is a chance for a member of the public to locate the missing spacecraft and help work out what went wrong, thanks to a new "Spot the Spacecraft" challenge:

The High-Resolution Imaging Science Experiment (HiRISE), based at the University of Arizona in Tucson, has a raft of images of the MPL’s projected landing area, but scans of the huge images came up blank.

So now, the HiRISE team’s blog has published 18 images, and has challenged the public to find the lost lander.

Can you find the MPL? The images can be viewed here.

We'll report more on the landing of the Phoenix Mars Lander after the 25th.

Technorati Tags: phoneix+mars+mission phoenix planets space solar+system science nasa mars mars+polar+lander mars+madness

Youngest Supernova Found

Wed, 14 May 2008 11:16:04 -0700

Very cool announcement from NASA this afternoon, uncovering the most recent supernova from 140 years ago:

"We can see some supernova explosions with optical telescopes across half of the universe, but when they're in this murk we can miss them in our own cosmic backyard," said Stephen Reynolds of North Carolina State University in Raleigh, who led the Chandra study. "Fortunately, the expanding gas cloud from the explosion shines brightly in radio waves and X-rays for thousands of years. X-ray and radio telescopes can see through all that obscuration and show us what we've been missing."
Astronomers regularly observe supernovae in other galaxies like ours. Based on those observations, researchers estimate about three explode every century in the Milky Way.
"If the supernova rate estimates are correct, there should be the remnants of about 10 supernova explosions that are younger than Cassiopeia A," said David Green of the University of Cambridge in the United Kingdom, who led the Very Large Array study. "It's great to finally track one of them down."
The tracking of this object began in 1985, when astronomers, led by Green, used the Very Large Array to identify the remnant of a supernova explosion near the center of our galaxy. Based on its small size, it was thought to have resulted from a supernova that exploded about 400 to 1000 years ago.
Twenty-two years later, Chandra observations revealed the remnant had expanded by a surprisingly large amount, about 16 percent, since 1985. This indicates the supernova remnant is much younger than previously thought.
That young age was confirmed in recent weeks when the Very Large Array made new radio observations. This comparison of data pinpoints the age of the remnant at 140 years - possibly less if it has been slowing down - making it the youngest on record in the Milky Way.
Besides being the record holder for youngest supernova, the object is of considerable interest for other reasons. The high expansion velocities and extreme particle energies that have been generated are unprecedented and should stimulate deeper studies of the object with Chandra and the Very Large Array.
"No other object in the galaxy has properties like this," Reynolds said. "This find is extremely important for learning more about how some stars explode and what happens in the aftermath."

More images here.

Here's an animation from the Chandra X-Ray Observatory:

In order to determine the age of G1.9+0.3, astronomers needed to track how quickly it is expanding. By comparing a radio image from 1985 to a Chandra image taken in 2007, scientists see the ring of debris expand. The expansion rate was confirmed with another radio observation with the VLA in 2008. The difference in size between these images gives clear evidence for expansion, allowing the age of the remnant and the time since the original supernova explosion (about 140 years) to be estimated.

Technorati Tags: smithsonian harvard supernova chandra nasa

Nice Science Project, Kid

Wed, 16 Apr 2008 08:18:14 -0700

"Der Junge aus Potsdam habe recht" -- that's what NASA said, as reported by the Potsdamer Neueste Nachrichten over the weekend. Translation: The boy from Potsdam is right:

Ein Potsdamer Schüler hat die Gefahr eines Asteroideneinschlags richtig berechnet und damit die Nasa blamiert. Was der 13-Jährige für das Jahr 2036 voraussagt, ist alles andere als beruhigend.

NASA figured there was a 1 in 45,000 chance the Apophis asteroid could collide with Earth. More like 1 in 450, according to Nico Marquardt. Here's the story in English, via the AFP:

A 13-year-old German schoolboy corrected NASA's estimates on the chances of an asteroid colliding with Earth, a German newspaper reported Tuesday, after spotting the boffins had miscalculated.
Nico Marquardt used telescopic findings from the Institute of Astrophysics in Potsdam (AIP) to calculate that there was a 1 in 450 chance that the Apophis asteroid will collide with Earth, the Potsdamer Neuerster Nachrichten reported.
NASA had previously estimated the chances at only 1 in 45,000 but told its sister organisation, the European Space Agency (ESA), that the young whizzkid had got it right.
The schoolboy took into consideration the risk of Apophis running into one or more of the 40,000 satellites orbiting Earth during its path close to the planet on April 13 2029.
Those satellites travel at 3.07 kilometres a second (1.9 miles), at up to 35,880 kilometres above earth -- and the Apophis asteroid will pass by earth at a distance of 32,500 kilometres.
If the asteroid strikes a satellite in 2029, that will change its trajectory making it hit earth on its next orbit in 2036.
Both NASA and Marquardt agree that if the asteroid does collide with earth, it will create a ball of iron and iridium 320 metres (1049 feet) wide and weighing 200 billion tonnes, which will crash into the Atlantic Ocean.
The shockwaves from that would create huge tsunami waves, destroying both coastlines and inland areas, whilst creating a thick cloud of dust that would darken the skies indefinitely.
The 13-year old made his discovery as part of a regional science competition for which he submitted a project entitled: "Apophis -- The Killer Astroid."

Technorati Tags: Nico+Marquardt esa nasa asteroid apophis potsdam

Black Holes & Taxes

Wed, 16 Apr 2008 08:17:52 -0700

Paid my taxes the other day -- yes, I had to pay. The forthcoming golden goose from the U.S. Treasury will act as a counter-balance, but I'm still paying up. Where does my money go?

The U.S. Defense Budget dwarfs hundreds of other counties' budgets combined -- in fact, the DoD overspent by $295 billion last year, reports the Christian Science Monitor. Does that include the "black budget?" The New York Times did a great piece on it on April Fools Day:

The classified budget of the Defense Department, concealed from the public in all but outline, has nearly doubled in the Bush years, to $32 billion. That is more than the combined budgets of the Food and Drug Administration, the National Science Foundation and the National Aeronautics and Space Administration.
Those billions have expanded a secret world of advanced science and technology in which military units and federal contractors push back the frontiers of warfare. In the past, such handiwork has produced some of the most advanced jets, weapons and spy satellites, as well as notorious boondoggles.
Budget documents tell little. This year, for instance, the Pentagon says Program Element 0603891c is receiving $196 million but will disclose nothing about what the project does. Private analysts say it apparently aims at developing space weapons.

More than the FDA, NSF and NASA budget combined? Dude, that's a black hole, which some find interesting. Hey, I'm all for space research and development, but a cure for cancer would be better

More interesting, in my opinion, was the news from the ESA press release yesterday about a "certified monster" black hole:

A team of Japanese astronomers using ESA’s XMM-Newton, along with NASA and Japanese X-ray satellites, has discovered that our galaxy’s central black hole let loose a powerful flare three centuries ago.

The finding helps resolve a long-standing mystery: why is the Milky Way’s black hole so quiescent? The black hole, known as Sagittarius A-star (A*), is a certified monster, containing about 4 million times the mass of our Sun. Yet the energy radiated from its surroundings is thousands of millions of times weaker than the radiation emitted from central black holes in other galaxies.
"We have wondered why the Milky Way’s black hole appears to be a slumbering giant," says team leader Tatsuya Inui of Kyoto University in Japan. "But now we realise that the black hole was far more active in the past. Perhaps it’s just resting after a major outburst."
The observations, collected between 1994 and 2005, revealed that clouds of gas near the central black hole brightened and faded quickly in X-ray light as they responded to X-ray pulses emanating from just outside the black hole. When gas spirals inward toward the black hole, it heats up to millions of degrees and emits X-rays. As more matter piles up near the black hole, the X-ray output becomes greater.

These X-ray pulses take 300 years to traverse the distance between the central black hole and a large cloud known as Sagittarius B2, so the cloud responds to events that occurred 300 years earlier.

1400-megapixel Camera to Change View of Universe

Wed, 09 Apr 2008 12:00:37 -0700

How many pixels? 1400-megapixel? That's 1.4 billion pixels, shutterbugs. And it won't fit in your pocket.

The camera is part of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), which promises to change our view of the Universe, producing the largest and most detailed map of the heavens ever produced. Defense Industry Daily reports the project is about to get $8 million in funding from the U.S. Air Force:

Kirkland AFB, NM recently gave the University of Hawaii of Honolulu, Hawaii a modified contract for $8 million for the Panoramic Survey Telescope and Rapid Response System (PanSTARRS) multi-year program. The initial effort to develop and deploy a telescope data management system was awarded via a Grant to the University of Hawaii (considered a Minority Institute) and “as the various phases progressed, the Air Force determined that a Cooperative Agreement would be the more appropriate instrument as now we would be substantially involved.” At this time all $8 million has been committed (FA9451-06-2-0338, P00002).

Located on top of a dormant volcano in Hawaii, the Pan-STARRS telescope will survey the visible sky, taking up to 1,000 exposures per night. In fact, this one telescope may be able to discover up to five times as many near-Earth asteroids as all present survey telescopes combined.

Check out this page for a comparison of what other observation platforms/systems can see: Hubble, Subaru, Pan-STARRS and Palomar Sky Survey. This is an amazing telescope, with 400 times the sensitivity of the Palomar Sky Survey.

Technorati Tags: hawaii nasa hubble subaru+observatory kirkland+afb pan-starrs nea asteroids

Yi!

Mon, 07 Apr 2008 09:24:19 -0700

Yi? Why, that's Korea's first astronaut. Yi So-yeon is scheduled to lift-off tomorrow, on a Russian Soyuz spacecraft, rolled to its launching pad earlier today. Symbolizing the historic trip, the rocket will depart from the same launch pad that Soviet Yury Gagarin, the first man in space, blasted off on in 1961.

The Russian-Korean crew has already bonded in the usual, Russian fashion – "The White Sun of the Desert":

As always with Russian space missions, the crew will sit down together before blast off to watch the old Soviet film "The White Sun of the Desert". The comedy classic boosts morale and is thought to bring the mission good luck.

Yi's historic stint in space will be very busy:

After a 50-hour flight, the Soyuz spacecraft will dock at the International Space Station on Thursday. There Yi will conduct several experiments until April 18, one day before she returns to Earth. The experiments include studies of the germination, growth and mutation of plants in space, the effects of micro-gravity on eye pressure, the effects of a space environment on the heart, and a study on gravitational effects on aging and genes. Yi will use fruit flies for the latter experiment since their life span is two weeks, making it possible to observe their growth to maturity during her 10-day stay. Having obtained a doctorate in bio and brain engineering from the Korea Advanced Institute of Science and Technology (KAIST) last February, Yi is considered well qualified for experiments involving biology, physics, and electronic engineering.

And Yi isn't about to conform to the usual NASA/RSA diets during her busy trip:

When it comes to dining, astronauts must live on space food they bring with them. Hundreds of kinds of space foods have been developed in the U.S. and Russia, made by freeze-drying items after they are sterilized by radiation. Yi will bring about a dozen Korean comestibles developed by the Korea Food Research Institute and Korea Atomic Energy Research Institute, including rice, kimchi, red pepper paste, soybean paste soup and instant noodles.

Technorati Tags: Soyuz Yi NASA RSA International+Space+Station Russia Korea

Lunar Eclipse APOD

Fri, 22 Feb 2008 05:11:54 -0800

Great image from the Astronomy Picture of the Day:

Technorati Tags: astronomy apod

Lunar Eclipse Tonight!

Wed, 20 Feb 2008 08:37:06 -0800

Here's one of the many fabled stories of how lunar eclipses have influenced history:

A lunar eclipse bailed Christopher Columbus out of a jam in Jamaica in 1504. Stranded there, ships damaged on a follow-up voyage to what would be called the Americas, Columbus and crew were starving because the natives refused to trade food for trinkets. The wily explorer consulted an almanac and learned a lunar eclipse would occur on Feb. 29, 1504. On that day, Columbus told the natives that God frowned on their lack of hospitality and would remove the moon from the sky if they didn't cooperate. The eclipse made good on the warning. The spooked natives promptly offered food if Columbus would bring back the moon, which natural events did for him. Well-supplied, Columbus and crew ultimately made it back to Europe.

While unlikely to improve relations with your neighbors, it's worth stepping out to see tonight's lunar eclipse. USA Today ran a great viewing guide yesterday. Some highlights:

Nearly a billion people in the Western Hemisphere, more than 1.5 billion in Europe and Africa, and perhaps another half-billion in western Asia will be able to watch — weather permitting...
The only problematic area will be along the Oregon and northern California coast, where the first partial stage of the eclipse will already be underway when the moon rises...
This eclipse comes with a rare bonus. The planet Saturn (magnitude +0.2) and the bright bluish star, Regulus (magnitude +1.4) will form a broad triangle with the moon's ruddy disk....this upcoming double event will be the only one of its kind occurring within the next millennium!

The European Space Agency and NASA both have viewing information, as well. For those in North America, this map tells you the time the eclipse will begin in your location. The short of it: 10:01 pm Eastern.

NASA also explains the color change during totality:

During an eclipse the moon changes color, going from a light gray color to an orange or deep red shade. This is totality. The moon takes on this new color because indirect sunlight is still able to pass through the Earth's atmosphere and cast a glow on the moon.
The exact color that the moon appears depends on the amount of dust and clouds in the atmosphere. If there are extra particles in the atmosphere, from say a recent volcanic eruption, the moon will appear a darker shade of red.

I can't think of any recent volcanic eruptions, do dark red may not be in the picture.

The next lunar eclipse will be on Dec. 21, 2010.

Technorati Tags: lunar+eclipse moon eclipse space astronomy solar+system skies

Nova Suprise for Astronomers on Mauna Kea

Tue, 29 Jan 2008 20:42:29 -0800

The Keck Interferometer -- two linked observatories in Hawaii (above, with Pu'u Poliahu in the background), located on the highest point in the Pacific -- give astronomers a new view of novae:

First results from a new NASA-funded scientific instrument at the W. M. Keck Observatory at Mauna Kea, Hawaii, are helping scientists overturn long-standing assumptions about powerful explosions called novae and have produced specific information about one nearby nova.
This sophisticated new system, called the Keck Interferometer, combines the observing power of the two 10-meter (33 feet) Keck telescopes into a single mega-telescope. Using the interferometer's "nulling" mode, data were taken by the Keck Interferometer team on a nearby nova called RS Ophiuchi.
In "nulling" mode, the Keck Interferometer suppresses the blinding light of a star so researchers can study the surrounding environment. The instrument helps them observe very faint objects near bright sources and produces 10 times more resolving power than a single Keck telescope working alone. It is the only instrument of its kind in operation.
The nulling mode was developed to search for dust regions around nearby stars, where planets might be forming, but the bright starlight poses a great challenge. "Because a star is so much brighter than the dust, something has to block the light, which is what the nuller does," said Rachel L. Akeson, Keck Interferometer project scientist at the California Institute of Technology's Michelson Science Center. "This technique turns out to be useful for lots of other kinds of objects, including this one, where dust is near a star that just went nova."
These nova data were taken by a team led by Wes Traub of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the data analysis and unified model for the nova were produced by a team led by Richard Barry and William Danchi of the Goddard Space Flight Center, Greenbelt, Md.
The star in the constellation Ophiuchus went nova at the perfect time for the team, on Feb. 12, 2006. "We were extremely lucky, because we had astronomers in place at two mountain-top interferometers, Keck in Hawaii and Infrared Optical Telescope Array in Arizona. Within minutes of hearing about the discovery of the nova, we alerted both teams to start observing it that night," said Traub, a senior research scientist at JPL.
The nova system, known as RS Oph consists of a white dwarf and a red giant. The red giant is gradually shedding its massive gaseous outer layers, and the white dwarf is sweeping up much of this wind, growing in mass over time. As the matter builds up on the white dwarf's surface, it eventually reaches a critical temperature that ignites a thermonuclear explosion that causes the system to brighten 600-fold. RS Oph was previously observed blowing its stack in 1898, 1933, 1958, 1967 and 1985, so astronomers were eagerly anticipating the 2006 eruption.
About three-and-a-half days after the nova was detected, the group observed the explosion with the Keck nuller. They set the instrument to cancel the nova's light, allowing them to see the much fainter surrounding material, and then the extremely bright blast zone.
The instrument's versatility was key to a surprising discovery. The nuller saw no dust in the bright zone, presumably because the nova's blast wave vaporized dust particles. But farther from the white dwarf, at distances starting around 20 times the Earth-sun distance, the nuller recorded the spectral chemical signature of silicate dust. The blast wave had not yet reached this zone, so the dust must have pre-dated the explosion.
"This flies in the face of what we expected. Astronomers had previously thought that nova explosions actually create dust," said Richard Barry of Goddard, lead author of the paper on the observations that will appear in the Astrophysical Journal. The team thinks the dust is created as the white dwarf plows through the red giant's wind, creating a pinwheel pattern of higher-density regions that is reminiscent of galaxy spiral arms. Inside these arms, atoms become cool enough and dense enough to allow atoms to stick together to form dust particles. The nova's blast wave has since destroyed RS Oph's pinwheel pattern, but it should re-form over the next few years, and future observations by NASA's Spitzer Space Telescope could see it. Barry is also coauthor of a paper based on Spitzer observations of RS Oph.
Most studies of RS Oph have relied on spectroscopic models, which have not been able to distinguish various nova components with as much detail as the interferometer. The Keck nuller measured one component of the RS Oph system to an accuracy of just 4 milliarcseconds, or about the size of a basketball seen 7,500 miles away.

Technorati Tags: keck+inferometer jpl mauna+kea hawaii+observatories nasa keck nulling

Solar Cycle 24

Tue, 08 Jan 2008 10:04:32 -0800

A new cycle of solar activity, officially "Solar Cycle 24," is upon us according to a NOAA press release:

A new 11-year cycle of heightened solar activity, bringing with it increased risks for power grids, critical military, civilian and airline communications, GPS signals and even cell phones and ATM transactions, showed signs it was on its way late yesterday when the cycle’s first sunspot appeared in the sun’s Northern Hemisphere, NOAA scientists said.
“This sunspot is like the first robin of spring,” said solar physicist Douglas Biesecker of NOAA’s Space Weather Prediction Center. “In this case, it’s an early omen of solar storms that will gradually increase over the next few years.”
A sunspot is an area of highly organized magnetic activity on the surface of the sun. The new 11-year cycle, called Solar Cycle 24, is expected to build gradually, with the number of sunspots and solar storms reaching a maximum by 2011 or 2012, though devastating storms can occur at any time.
During a solar storm, highly charged material ejected from the sun may head toward Earth, where it can bring down power grids, disrupt critical communications, and threaten astronauts with harmful radiation. Storms can also knock out commercial communications satellites and swamp Global Positioning System signals. Routine activities such as talking on a cell phone or getting money from an ATM machine could suddenly halt over a large part of the globe.

The discussion on Slashdot ranged from light polarity to global warming to AIDS research, which may or may not be entertaining, depending on your point of view.

You can bet the Big Bear Solar Observatory will be watching this intently. It may be in California, but it's run by the New Jersey Institute of Technology (NJIT).

Having your ATM machines go cold suddenly is probably because that location depends on a VSAT terminal to process transactions, which uses a geosynchronous communications satellite to connect to the banking system. If that VSAT network uses an AMERICOM satellite, hopefully it won't be a problem (disclosure: AMERICOM underwrites this blog). The satellites that AMERICOM operates are designed to withstand the effects of extreme solar events, categories S5 and G5, and with more than the predicted number of events of all levels over the life of each satellite as part of the design. Electronic components that are known to degrade in the presence of solar radiation have been "oversized" to degrade acceptably and operate nominally during the expected radiation exposure associated with soloar storms. In addition, shielding is utilized to reduce the exposure of electronic components to the effects of solar radiation and geomagnetic storms.

As always, check SpaceWeather for the latest developments.

Technorati Tags: sunspots cme coronal+mass+ejection solar+activity noaa solor+cycle satellite njit

DIY Friday: Tuning Your Newtonian Reflector

Fri, 04 Jan 2008 16:54:09 -0800

The tuning of a telescope is actually called "collimation," and Sky and Telescope shows you how:

To get your telescope well collimated, here is what you need to accomplish:
Step 1: Center the secondary mirror on the axis of the focuser drawtube.
Step 2: Aim the eyepiece at the center of the primary mirror.
Step 3: Center your primary mirror's sweet spot in the eyepiece's field of view.
In most cases, only the last of these three steps will need to be repeated regularly; the first two are more or less set-and-forget operations. Now let's get to the nuts and bolts of actually collimating your reflector

It's a rather simple telescope and could build one yourself for about $150.

Technorati Tags: newtonian+reflector telescope astronomy stargazing

Heading North for the Ursids

Thu, 13 Dec 2007 08:43:44 -0800

Normally the Ursids meteor shower isn't that spectacular, and when it peaks this year around the 22nd of December, a bad moon will make viewing it difficult in Europe and Asia, and it will be daytime in North America. So why is Peter Jenniskens, a meteor astronomer at the Carl Sagan Center and SETI Institute, travelling all the way to the North Pole to view it this year?

Peter explains that it's the presence of Comet 8P/Tuttle (pictured above) within the shower, and a long-standing mystery or the Ursids' outbursts, that are bringing him high over the North Pole:

We are preparing to visit the North Pole on December 22, to see an unusual meteor shower called the Ursids. This meteor shower radiates from the constellation known as the Little Dipper: Ursa Minor. This minor shower is quite unremarkable in most years, but this year the parent comet 8P/Tuttle is approaching, and it has a strong Perseid-level shower in store for us. We think. We predict a peak time around 20 - 22.2 Universal Time and a width of 5 to 8.5 hours at half the peak rate.

Unfortunately, that means that North America is not a good place to be, for our purpose. The outburst will happen during our daytime. Best viewing will be in Asia and Europe. Even from those locations it won't be easy to see this shower, because of a bad moon that night, and frequent bad weather in December...

The Ursid outburst is too rare an opportunity to miss, though, because the comet returns only every 13.6 years. This time around, the comet comes closer to us than ever before, at least since it was discovered in 1790, passing at only 0.25 AU on January 5....

The Ursid outbursts are somewhat of a mystery. They have been heard, more than seen, in the years around past returns of the comet, by people listening for distant radio stations. Each time a meteor appeared in the cold winter sky, it would create a trail of ions, which reflected radio waves to the observer. They would hear a brief "ping". While counting those pings, it was clear to those listeners that something unusual was happening on December 22 in some years.

In collaboration with Esko Lyytinen of Helsinki, Finland, and Jeremie Vaubaillon of Caltech, I investigated these reports, and we discovered that the dust may have been ejected by comet Tuttle around AD 300 to 900, or perhaps earlier. Results will be published in the upcoming December issue of the Journal of the International Meteor Organization. It takes a long time for the dust to move from an orbit similar to that of the comet into an orbit that can hit Earth. Close encounters of Jupiter near the ascending node of the comet orbit seem to play an important role, especially when they occur shortly after the dust has been ejected and is still concentrated in space. The dust itself is most affected when its motion around the sun "rings," or resonates, with that of Jupiter.

The upcoming outburst is a great opportunity to test this model. When the Earth travels through the stream of dust, we may hope to see the dominance of some particular returns of the comet in the past, when all the dynamics worked in our favor. This could cause a particular peak time and rate profile of the shower.

To investigate this, we are hoping for an opportunity to observe the outburst from a Gulfstream V aircraft in a mission similar to our campaign to study the September 1 Aurigids. If approved, the Ursid flight will be a long 16-hour mission, involving one aircraft, departing from NASA Ames Research Center in the early morning of December 22nd. The plane will fly north-west towards Alaska, land in Anchorage for a refuel stop, and then continue on to follow the Earth's shadow, fly over the Arctic and turn towards Canada to return at Ames just after sunset. We don't need to fly all the way to the North Pole, just far enough north to stay in darkness all the time. The aircraft will follow the Earth's rotation, making the meteors fall from a radiant high in the sky throughout the mission. The moon will stay low on the horizon on one side of the plane.

16 hours? That's a long flight in a cold place. The flight path of Jenniskens' Gulfstream V can be found here and here; the Federation des Astronomes Amateurs du Quebec also has some good finder charts here. Finally, for spotting Comet 8P/Tuttle, this finder chart is helpful.

Happy comet and meteor gazing!

Technorati Tags: astronomy Comet+8P/Tuttle comets meteors ursids science

The Earth in HD

Thu, 08 Nov 2007 09:32:50 -0800

In September, we discussed the launch Japan's lunar study, KAGUYA – what many consider the most sophisticated lunar exploration mission in the post-Apollo Era. KAGUYA is already showing results, bringing us the first high definition image of Earth (link):

The photograph was taken from a distance of 110,000 km– hundreds of times further away from Earth than any spaceship with similar capabilities had ever been. After taking these breathtaking images, KAGUYA went on to orbit the Moon and then released a baby satellite as part of its ongoing lunar exploration mission.

Until recently there were only three possible ways to photograph Earth from a distance of several hundred kilometers- via a Space Shuttle, via the International Space Station (ISS) or via orbiting satellites. Now, thanks to the KAGUYA Lunar explorer, which was launched by the Japan Aerospace Exploration Agency (JAXA) and the Japan Broadcasting Corporation (NHK), we can see Earth in its full glory, as it is from afar.

In September 2007, JAXA launched the KAGUYA (SELENA: Selenological and Engineering Explorer) into space. It is composed of a main orbiting satellite and two smaller satellites in polar orbit, and is equipped with instruments for scientific investigation of the Moon.

KAGUYA's (SELENA) main mission is to collect scientific data from the Moon that will be used to explore the possibility of utilizing the Moon in the future. The three HD CCD 2.2 Mega-pixel cameras onboard the KAGUYA were developed by Japan's Broadcasting Corporation specifically for this mission. In addition to the cameras, the ship is equipped with 13 other scientific instruments which will be used to explore the Moon.

The abovementioned image was processed from a high resolution video that was shot periodically over eight minutes, on September 29th, 2007. When looking at the image, one can see the outlines of the west coast of South America quite distinctively.

And we have hi-def images of the moon, as well:

This is a still image taken out from the first moving image shooting when the KAGUYA flew from the northern area of the Oceanus Procellarum to the centre of the North Pole. As the altitude near the North Pole is high, the angle of the coming sunlight was lower, thus the shade of the crater topography looks long in the image. The moving image was taken at 4:07 AM on 31 October 2007 (JST) by eight-fold speed intermittent shooting (eight minutes is converged to one minute) from the KAGUYA, and the data was received at the JAXA Usuda Deep Space Centre on the same day.

A video of the moon captured by the HDTV camera is available here.

Technorati Tags: KAGUYA HDTV lunar+photo JAXA lunar+study earth+image