Universe Today

February 12, 2014December 23, 2015 by David Dickinson

Space Station to Get a ‘Laser Cannon’

CATS in the laboratory. Credit: NASA/GSFC.

What’s a space station without a laser cannon?

The International Space Station will be getting its very own laser at the end of 2014. And unlike the planet-smashing capabilities of the Death Star of Star Wars fame, this laser will to be enlisted for the purpose of science.

It’s called CATS, and no, it isn’t the latest attempt to put feline astronauts in space. CATS stands for the Cloud Aerosol Transport System. The goal of CATS is to study the distribution of tiny particles of dust and air contaminants known as aerosols.

Developed by research scientist Matt McGill at NASA’s Goddard Space Flight Center in Greenbelt Maryland, CATS is slated to head to the International Space Station later this year on September 12th aboard SpaceX’s CRS-5 flight of the Dragon spacecraft. CATS will be installed on the Japanese Experiment Module-Exposed Facility (JEM-EF) and will demonstrate the utility of state-of-the-art multi-wavelength laser technology to study aerosol distribution and transport in the atmosphere.

Such knowledge is critical in understanding the path and circulation of aerosols and pollutants worldwide. When the Eyjafjallajökull volcano erupted in Iceland back in 2010, many trans-Atlantic flights were grounded as a precaution. These measures are necessary as several flights have suffered engine failures in the past due to encounters with volcanic ash clouds, such as the four engine failure of KLM Fight 867 in 1989 and the British Airways Flight 9 incident over Southeast Asia in 1982. Knowing where these dangerous ash clouds are is crucial to the safety of air travel.

The expanding ash cloud spewing from Iceland's Eyjafjallajökull volcano as seen from space in 2010. Credit: NASA. — The expanding ash cloud spewing from Iceland’s Eyjafjallajökull volcano as seen from space in 2010. Credit: NASA.

To accomplish this, CATS will emit 5,000 1 milliJoule laser pulses a second at the 1064, 532 and 355 nanometer wavelengths. This represents a vast improvement in power requirements and thermal capabilities over a similar instrument currently in service aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) Earth remote sensing spacecraft.

And it’s that third 355 nanometer wavelength that will make CATS stand out from CALIPSO. This will also allow researchers to differentiate between particle size and measure the horizontal and vertical distribution of aerosol particles in the atmosphere. CATS will also be capable of measuring the number of individual photons being reflected back at it, which will provide a much better resolution and understanding of current atmospheric activity.

“You get better data quality because you make fewer assumptions, and you get, presumably, a more accurate determination of what kind of particles you’re seeing in the atmosphere,” McGill said in a recent press release.

The International Space Station also provides a unique vantage point for CATS. In a highly inclined 51.7 degree orbit, the station passes over a good swath of the planet on 16 orbits daily on a westward moving ground track that repeats roughly every three days. This will assure CATS has coverage over a large percentage of the planet, including known pollutant transport routes across the northern Pacific and down from Canada over the U.S. Great Lakes region.

While the first two lasers will operate in the infrared and visual wavelengths, said third laser will work in the ultraviolet. And while this will give CATS an enhanced capability, engineers also worry that it may also be susceptible to contamination. “If you get contamination on any of your outgoing optics, they can self-destruct, and then your system is dead. You end up with a very limited instrument lifetime,” McGill said.

Still, if CATS is successful, it may pave the way for larger, free-flying versions that will monitor long-range atmospheric patterns and shifts in climate due to natural and man-made activity. And the ISS makes a good platform to test pathfinder missions like CATS at low cost. “In our current budget-constrained environment, we need to use what we already have, such as the [station], to do more with less,” McGill said.

CALIPSO's LiDAR imaged from the ground by Gregg Hendry in 2008. Used with permission. — CALIPSO’s LiDAR imaged from the ground by Gregg Hendry in 2008. Used with permission.

The advent of a LiDAR system aboard the ISS has also generated a spirited discussion in the satellite tracking community concerning prospects for spotting CATS in operation from the ground. The CALIPSO LiDAR has been captured by ground spotters in the past. However, CALIPSO fires a much more powerful 110 milliJoule pulse at a rate of 20 times a second. Still, the lower power CATS system will be firing at a much faster rate, delivering a cumulative 5,000 milliJoules a second. CATS won’t be bright enough to show up on an illuminated pass of the ISS, but it just might be visible during darkened passes of the ISS through the Earth’s shadow. And, unlike CALLIPSO — which is part of the difficult to observe A-Train of Earth-observing satellites — the ISS passes in view of a majority of humanity. At very least, activity from CATS will be worth watching out for, and may well be seen either visually or photographically.

We’ll soon be adding CATS to the long list of outstanding science experiments being conducted aboard the International Space Station, and the sight of this “fully armed and operational battle station” may soon be coming to a dark sky site near you!

February 12, 2014December 23, 2015 by Shannon Hall

Experts Question Claim Tunguska Meteorite May Have Come from Mars

In 1908 a blazing white line cut across the sky before exploding a few miles above the ground with a force one thousand times stronger than the nuclear blast that leveled Hiroshima, Japan.

The resulting shock wave felled trees across more than 800 square miles in the remote forests of Tunguska, Siberia.

For over 100 years, the exact origins of the Tunguska event have remained a mystery. Without any fragments or impact craters to study, astronomers have been left in the dark. That’s not to say that all kinds of extraordinary causes haven’t been invoked to explain the event. Various people have thought of everything from Earth colliding with a small black hole to the crash of a UFO.

Russian researchers claim they may finally have evidence that will dislodge all conspiracy theories, but that “may” is huge. A team of four believes they have recovered fragments of the object — the so-called Tunguska meteorite — and even think they are Martian in origin. The research, however, is being called into question.

In a detective-like manner, the team surveyed 100 years’ worth of research. The researchers read eyewitness reports and analyzed aerial photos of the location. They performed a systematic survey of the central region in the felled forest and analyzed exotic rocks and penetration funnels.

A schematic of the Tunguska event. Image Credit: — A schematic of the central region in the felled forest due to the Tunguska event. Image Credit: Anfinogenov et al.

Previously, numerous expeditions failed to recover any fragments that could be attributed conclusively to the long-sought Tunguska meteorite. But then Andrei Zlobin, of the Russian Academy of Sciences’ Vernadsky State Geological Museum, discovered three stones with possible traces of melting. He published the results in April 2013.

Zlobin’s discovery paper was received with skepticism and Universe Today covered the news immediately. A curious question arose quickly: why did it take so long for Zlobin to analyze his samples? The expedition took place in 1988, but it took 20 years before the three Tunguska candidates were nominated and another five years before Zlobin finished the paper.

By Zlobin’s admission, his discovery paper was only a preliminary study. He claimed he didn’t carry out a detailed chemical analysis of the rocks, which is necessary in order to reveal their true nature. Most field experts quickly dismissed the paper, feeling there was more work to be done before Zlobin could truly know if these rocks were fragments from the Tunguska meteor.

Today, new research is moving forward with an analysis of the rocks originally discovered by Zlobin. But an interesting new addition to the collection is a rock called “John’s Stone” — a large boulder discovered in July, 1972. While it’s mostly a dark gray now it was much lighter at the time of its discovery. “John’s Stone has an almond-like shape with one broken side,” lead author Dr. Yana Anfinogenov told Universe Today.

Now the skeptical reader might be asking the same question as before: why is there such a large time-lapse between the discovery of John’s Stone and the analysis presented here? (It’s interesting to note that while this elusive rock has been reviewed in the literature for over 40 years, this is the first time it has appeared in an English paper). Anfinogenov claimed that new data (especially concerning Martian geology) allowed for a much better analysis today than it did in recent years.

Photos (1972) of John's Stone and related findings. Image Credit: — Photos (1972) of John’s Stone and related findings. Image Credit: Anfinovenov et al.

“The ground near John’s Stone presents undeniable impact signs suggesting that the boulder hit the ground with a catastrophic speed,” Anfinogenov told Universe Today. It left a deep trace in the permafrost which allowed researchers to note its trajectory and landing velocity coincides with that of the incoming Tunguska meteorite.

John’s Stone also contains shear-fractured splinter fragments with glossy coatings, indicating the strong effect of heat generated when it entered our atmosphere. The research team attempted to reproduce those glossy coatings found on the splinters by heating another fragment of John’s Stone to 500 degrees Celsius. The experiment was not successful as the fragment disintegrated in high heat.

“The authors do not present a strong case that the boulder known as John’s Stone was involved in the Tunguska event, or that it originated from Mars,” said Dr. Phil Bland, a meteorite expert at Curtin University in Perth, Australia.

They claim the mineral structure and chemical composition of the rocks — a quartz-sandstone with grain sizes of 0.5 to 1.5 cm and rich in silica — match rocks found on Mars. But their paper lacks any microanalysis of the samples, or isotopic study.

While there is a strong case that an impact on Mars could easily eject rock fragments that would then hit the Earth, something doesn’t match up. “The physics of ejecting material from Mars into interplanetary space argues for fragments with diameters of one to two meters, not the 20 to 30 meter range that would be required for Tunguska,” Bland told Universe Today.

It seems as though planetary geologists will require a much stronger case than this to be truly convinced John’s Stone is the Tunguska meteorite, let alone from Mars.

The paper is currently under peer-review but is available for download here.

February 12, 2014December 23, 2015 by Ken Kremer

Time for Earth to bid China’s Yutu Moon Rover Farewell ?

Farewell Yutu - artistic impression of Earthrise over Yutu at lunar landing site. This composite photomosaic combines farewell view of China’s Yutu rover with Moon’s surface terrain at Mare Imbrium landing site and enlarged photo of Earth, all taken by Chang’e-3 lander. Not a science image. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com

Farewell Yutu – artistic impression of Earthrise over Yutu at lunar landing site. This composite timelapse photomosaic combines farewell view of China’s Yutu rover with Moon’s surface terrain at Mare Imbrium landing site and enlarged photo of Earth – all actual images taken by Chang’e-3 lander. Not a science image. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com
See complete Yutu timelapse panorama below and at NASA APOD Feb. 3, 2014:http://apod.nasa.gov/apod/ap140203.html
Story and Headline revised and updated[/caption]

Update: There might yet be hope for Yutu. Amateur radio operators at UHF-satcom reported detection of a signal from Yutu today. But no update has been reported on the China News Service website or other official state media. Yutu’s fate is unknown.]

Update 2: Yutu is alive. story and headline revised. Further details – here
………..

For a time, it seemed China’s maiden moon rover ‘Yutu’, beloved by millions worldwide, had been lost.

The apparently unfortunate and sad breaking news was just reported today in an ultra brief dispatch by the English language version of Chinadaily – with the headline “Loss of lunar rover.”

But the death notice by Chinese officials turned out to be premature when a signal was detected a day later.

It had been thought that Yutu froze to death due to a pre-hibernation mechanical malfunction and failed to wake up and communicate with China’s mission controllers in Beijing on Monday, Feb. 10, when daylight returned to the rovers Moon landing site at Mare Imbrium (Sea of Rains) at the start of what would have been Lunar Day 3 for the mission.

“China’s first lunar rover, Yutu, could not be restored to full function on Monday [Feb. 10] as expected,” wrote the state owned Chinadaily.com, China News Service agency.

The cause of the pre-hibernation malfunction may perhaps be traced back to a buildup of abrasive lunar dust, but no one knows at this time.

Note: This story has been updated as further details emerged.

Portrait photo of Yutu moon rover taken by camera on the Chang'e-3 moon lander on Dec. 15, 2013 shortly after rolling all 6 wheels onto lunar surface. Credit: Chinese Academy of Sciences — Portrait photo of Yutu moon rover taken by camera on the Chang’e-3 moon lander on Dec. 15, 2013 shortly after rolling all 6 wheels onto lunar surface. Credit: Chinese Academy of Sciences

Yutu has touched the hearts of countless Earthlings since the history making landing on the desolate gray plains of the the Moon atop the Chang’e-3 lander two month ago on Dec. 14, 2013.

See our timelapse mosaic, artistic impression of Earthrise over Yutu – above – by the image processing team of Ken Kremer and Marco Di Lorenzo.

It combines real images of the Moon’s surface terrain with an intentionally enlarged photo of Earth – all snapped by the Chang’e-3 lander – as a homage to the mission.

See the complete timelapse mosaic herein and featured at NASA APOD on Feb 3, 2013.

Although definitive word about the Chang’e-3 lander has not yet been announced, it is expected to survive and has a 1 year design lifetime.

Potentially bad news about Yutu’s fate was not unexpected however, after Chinese space officials disclosed that the rover “experienced a mechanical control abnormality” two weeks ago, just as her 2nd lunar night was to begin, according to a report by China’s official government newspaper, The People’s Daily.

“Yutu experienced mechanical problems on Jan 25 and has been unable to function since then,” according to Chinadaily.com, China News service.

360-degree time-lapse color panorama from China’s Chang’e-3 lander This 360-degree time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at three different positions during its trek over the Moon’s surface at its landing site from Dec. 15-22, 2013 during the 1st Lunar Day. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com — 360-degree time-lapse color panorama from China’s Chang’e-3 lander
This 360-degree time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at three different positions during its trek over the Moon’s surface at its landing site from Dec. 15-22, 2013 during the 1st Lunar Day.
Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo – kenkremer.com
See our Yutu timelapse pano also at NASA APOD Feb. 3, 2014:
http://apod.nasa.gov/apod/ap140203.html

Each lunar day and night lasts for alternating periods of 14 Earth days.

The six wheeled Yutu rover and Chang’e-3 mothership lander had just finished sleeping through the terribly frigid two week long lunar night since they entered their second hibernation period on Jan. 24th and 25th respectively, and Chinese space engineers had hoped to reawaken both probes in the past few days.

No communications are possible during the period of nighttime dormancy.

This time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at two different positions during its trek over the Moon’s surface at its landing site from Dec. 15-18, 2013. This view was taken from the 360-degree panorama. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo. See our complete Yutu timelapse pano at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm — This time-lapse color panorama from China’s Chang’e-3 lander shows the Yutu rover at two different positions during its trek over the Moon’s surface at its landing site from Dec. 15-18, 2013. This view was taken from the 360-degree panorama, herein. Credit: CNSA/Chinanews/Ken Kremer/Marco Di Lorenzo. See our complete Yutu timelapse pano also at NASA APOD Feb. 3, 2014: http://apod.nasa.gov/apod/ap140203.htm

Yutu, which translates as ‘Jade Rabbit’ is named after the rabbit in Chinese mythology that lives on the Moon as a pet of the Moon goddess Chang’e.

The piggybacked pair of Chinese probes safely touched down on the Moon at Mare Imbrium near the Bay of Rainbows on Dec. 14, 2013.

Photo of Chang'e-3 moon lander emblazoned with Chinese national flag taken by the panoramic camera on the Yutu moon rover on Dec. 22, 2013. Credit: CNSA — Photo of Chang’e-3 moon lander emblazoned with Chinese national flag taken by the panoramic camera on the Yutu moon rover on Dec. 22, 2013. Credit: CNSA

Apparently one of Yutu’s solar panels did not fold back properly over the instrument laden mast after it was lowered to a horizontal position into a warmed electronics box where it is shielded and insulated from the extremely frigid lunar night time temperatures.

Dust accumulation on the rover and gears may possibly be to blame for the failure to retract, based on unofficial accounts.

China has not released any official or detailed information on the cause of the malfunction or recovery actions taken by Chinese space engineers.

Such a malfunction could spell doom for the fragile electronic and computer components in the unprotected mast mounted instruments and systems, including the color and navigation cameras and the high gain antenna.

During each 14 Earth-day long night, the Moon’s temperatures plunge dramatically to below minus 180 Celsius, or minus 292 degrees Fahrenheit.

‘Jade Rabbit’ had departed the landing site forever, and was journeying southwards as the incident occurred – about six weeks into its planned 3 month long moon roving expedition to investigate the moon’s surface composition and natural resources.

The 140 kg Yutu robot drove off a pair of ramps and onto the moon seven hours after the Dec. 14, 2013 touchdown.

The 1200 kg stationary lander is expected to return science data about the Moon and telescopic observations of the Earth and celestial objects for at least one year.

Chang’e-3 and Yutu landed on a thick deposit of volcanic material.

Chang’e-3 lander and Yutu rover – from Above And Below Composite view shows China’s Chang’e-3 lander and Yutu rover from Above And Below (orbit and surface) – lander color panorama (top) and orbital view from NASA’s LRO orbiter (bottom). Chang’e-3 lander color panorama shows Yutu rover after it drove down the ramp to the moon’s surface and began driving around the landers right side to the south. Yellow lines connect craters seen in the lander panorama and the LROC image from LRO (taken at a later date after the rover had moved), red lines indicate approximate field of view of the lander panorama. Credit: CNSA/NASA/Ken Kremer/Marco Di Lorenzo/Mark Robinson — Chang’e-3 lander and Yutu rover – from Above And Below
Composite view shows China’s Chang’e-3 lander and Yutu rover from Above And Below (orbit and surface) – lander color panorama (top) and orbital view from NASA’s LRO orbiter (bottom). Chang’e-3 lander color panorama shows Yutu rover after it drove down the ramp to the moon’s surface and began driving around the landers right side to the south. Yellow lines connect craters seen in the lander panorama and the LROC image from LRO (taken at a later date after the rover had moved), red lines indicate approximate field of view of the lander panorama. Credit: CNSA/NASA/Ken Kremer/Marco Di Lorenzo/Mark Robinson

They were designed to conduct their science investigations and work independently of one another.

China can be proud of its magnificent space flight accomplishment.

Chang’e-3 was the first spacecraft from Earth to soft land on the Moon in nearly four decades since the touchdown of the Soviet Union’s Luna 24 sample return spacecraft back in 1976.

America’s last visit to the Moon’s surface occurred with the manned Apollo 17 landing mission – crewed by astronauts Gene Cernan and Harrison ‘Jack’ Schmitt , who coincidentally ascended from the lunar soil on Dec. 14, 1972 – exactly 41 years before Chang’e-3.

China’s follow on Chang’e-4 Moon lander is due to blastoff in 2015.

Surely the science and engineering team will incorporate valuable lessons learned.

China is only the 3rd country in the world to successfully soft land a spacecraft on Earth’s nearest neighbor after the United States and the Soviet Union.

Stay tuned here for Ken’s continuing Chang’e-3, Orion, Orbital Sciences, SpaceX, commercial space, LADEE, Mars and more planetary and human spaceflight news.

Ken Kremer

Landing site of Chinese lunar probe Chang'e-3 on Dec. 14, 2013. — Landing site of Chinese lunar probe Chang’e-3 on Dec. 14, 2013.

February 11, 2014December 23, 2015 by Ken Kremer

Science Instruments Perfect as NASA’s MAVEN Orbiter Speeds to Red Planet

MAVEN is NASA’s next Mars Orbiter and will investigate how the planet lost most of its atmosphere and water over time. Credit: NASA

NASA’s newest Mars orbiter, the Mars Atmosphere and Volatile Evolution (MAVEN) probe passed a significant interplanetary milestone with the announcement that all of the craft’s science instruments were activated and passed their initial checkout.

“I’m delighted that we’re operating in space so well,” Bruce Jakosky, MAVEN’s Principal Investigator told Universe Today.

“We’re on our way!”

Earth is now clearly in the rear view mirror and fading with each passing day.

The $671 Million MAVEN spacecraft’s goal is to study Mars upper atmosphere to explore how the Red Planet may have lost its atmosphere and water over billions of years.

The MAVEN probe carries nine sensors in three instrument suites to study why and exactly when did Mars undergo the radical climatic transformation.

“I’m really looking forward to getting to Mars and starting our science!” Jakosky told me.

MAVEN aims to discover the history of water and habitability stretching back over billions of years on Mars.

It will measure current rates of atmospheric loss to determine how and when Mars lost its atmosphere and water.

MAVEN thundered to space nearly three months ago on Nov. 18, 2013 following a flawless blastoff from Cape Canaveral Air Force Station’s Space Launch Complex 41 atop a powerful Atlas V rocket and thus began a 10 month interplanetary voyage from Earth to the Red Planet.

NASA’s Mars bound MAVEN spacecraft launches atop Atlas V booster at 1:28 p.m. EST from Space Launch Complex 41 at Cape Canaveral Air Force Station on Nov. 18, 2013. Image taken from the roof of the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center. Credit: Ken Kremer/kenkremer.com

“I can’t tell you how exciting this is to be now only seven and a half months from getting to Mars,” Jakosky gushed.

Further instrument checkouts are planned as the orbiter streaks closer to Mars including tesating to the Electra communications package that will serve as a critical relay for NASA’s surface rovers including Curiosity, Opportunity and the planned 2020 rover.

“The second Trajectory Correction Maneuver (TCM-2) is scheduled for Feb. 26,” said Jakosky.

MAVEN’s trajectory from Earth to Mars. MAVEN arrives at Mars on Sept. 22, 2014 some ten months after launch on Nov. 18, 2013. Credit: NASA

TCM thruster firings insure that the spacecraft is exactly on course for the do or die orbital insertion maneuver when MAVEN arrives on September 22, 2014.

To date MAVEN has flown over 137 million miles (221 million km) of its total 442 million miles (712 million km) path to Mars. It is speeding around the sun at 69,480 mph or 31.06 kps.

“The performance of the spacecraft and instruments to date bears out all the hard work the team put into testing the system while it was on the ground,” said David Mitchell, MAVEN project manager at NASA’s Goddard Space Flight Center in Greenbelt, Md, in a statement.

“The way that the operations team has performed while flying the system has been nothing short of outstanding. We have big events ahead of us before we can claim success but I am very pleased with how things have gone thus far.”

MAVEN is not alone in the frigid vacuum of space. She is joined by India’s Mars Orbiter Mission (MOM) orbiter in pursuit of Mars to fortify Earth’s invasion fleet.

MOM will reach Mars vicinity on Sept. 24, just two days after the arrival MAVEN on Sept. 22, 2014.

Stay tuned here for Ken’s continuing MAVEN, Curiosity, Opportunity, Chang’e-3, SpaceX, Orbital Sciences, LADEE, MOM, Mars and more planetary and human spaceflight news.

Ken Kremer

February 11, 2014December 23, 2015 by Ian Steer

How Supernova 2014J Will Help Determine the Extragalactic Distance Scale and Impact Cosmology

Comparison images from just before the supernova in M82 until Feb 7, 2014. Credit and copyright: Tom Wildoner.

In only three weeks since its discovery on January 21, 2014, much has been learned about the new supernova SN 2014J in Messier 82, the “Cigar” galaxy. In addition to early confirmation based on its spectrum that it is indeed a type Ia supernova, it is now understood to be the nearest type Ia explosion to our Milky Way galaxy since 1986.

Its unique proximity alone makes SN 2014J one the most important supernova ever observed. It will impact our understanding both of the type Ia-class of supernovae and of the Universe as a whole, because our Universe’s size, age, and ultimate fate are linked intimately to observations of type Ia supernovae, and because the precision with which they can be applied to estimate Universal-scale distances depends crucially on the nearest examples. SN 2014J is very likely to remain the nearest anchor-point in the type Ia supernovae-based distance scale for decades to come.

“Being the nearest supernova of this kind, SN 2014J will help us to better calibrate the expansion of the Universe,” said Adam Riess, co-leader of the Supernova H0 for Equation of State (SHOES) project, and co-winner of the 2011 Nobel Prize in Physics.

Observations of type Ia supernovae led to the discovery that our Universe is made mostly of dark energy, and that its expansion rate is apparently accelerating. That discovery earned the 2011 Nobel Prize in Physics for Riess, Saul Perlmutter, and Brian Schmidt.

Measuring ever more accurately our Universe’s exact expansion rate has been the Holy Grail of cosmology since Hubble’s discovery of expansion in 1929. Type Ia are perfect for probing cosmological scale distances, because these stellar explosions occur only when white dwarf stars exceed a certain critical mass, equivalent to 1.4 solar masses.

M82 with Supernova 2014J imaged on January 23, 2014. Credit and copyright: Anna Morris.

As a result, most type Ia supernova explode with roughly the same intrinsic or absolute magnitude. They therefore provide a unique kind of “standard candle,” by which any type Ia supernova observed to be one hundred times fainter than another can be understood to be exactly ten times farther than the other. In practice, subtle differences between actual type Ia supernovae, amounting to around ten percent on average in their net effect on distance estimates, are accounted for. Technically, therefore, type Ia supernova provide “standardizable candles.”

Normal type Ia supernovae are well understood. Within just days of its discovery, Robert Quimby of the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo was able to predict the peak apparent magnitude of m_V = 10.5 and time of peak brightness of February 2 for SN 2014J, more than a week prior to their occurrence. As observations now available show, as summarized in the light-curve available thanks to the American Association of Variable Star Observers, Quimby’s prediction based on the light-curves of other similar type Ia supernova, was spot on (see Figure 1, below).

Light curves for SN 2014J and SN 2011fe, the next nearest type Ia supernova, show blue magnitudes are ~1.3 mag fainter (blue dots) than visual magnitudes (green dots) for SN 2014J, due to obscuring dust in host galaxy Messier 82, compared to the normal, non-obscured, and nearly over-lapping blue and visual magnitudes for SN 2011fe. Courtesy of the American Association of Variable Star Observers.

While SN 2014J is a normal type Ia supernova, its light-curve reveals it is highly reddened, as in dimmed and obscured by large amounts of dust present and intervening in its host galaxy. The amount of reddening is indicated by the difference between the blue and visual magnitudes. Known as extinction, measured as E = (B-V), for SN 2014J the extinction amounts to ~1.3 mag. That compares to the next nearest recent type Ia supernova, SN 2011fe in galaxy Messier 101, at 23 million light-years (7.0 Megaparsecs). It’s light-curve shows SN 2011fe was reddened very little in comparison, i.e.- both spectrum and colour are normal.

The date of SN 2014J explosion’s first light has now been established to be January 14.72 UT, around one week prior to discovery January 21. That was reported in one of at least two papers already published online regarding SN 2014J, the one by WeiKang Zheng et al., and which has already been submitted to Astrophysical Journal Letters (see e-print here). SN 2014J is one of only four type Ia supernova with observations as early as one day after first light, the others including SN 2011fe mentioned, and SN 2009ig in galaxy NGC 1015 at 130 million light-years (41 Megaparsecs), and SN 2013dy in galaxy NGC 7250 at 46 million light-years (14 Megaparsecs).

Two rivals for nearest recent type Ia supernovae, SN 1972E in galaxy NGC 5253 and SN 1986G in NGC 5128, the Centaurus A galaxy, were cited early. Neither however, are argued to be directly relevant to the current distance scale zero point because neither have modern, complete, multi-band and multi-epoch observations including pre-maximum observations, which are quintessential to defining zero point type Ia supernovae, and data that is now being gathered for SN 2014J. For example, SN 2002fk in galaxy NGC 1309 at 100 million light-years (31 Megaparsecs) is one of only eight type Ia supernovae employed as zero point calibrators, because of their complete, multi-epoch, multi-band light-curve data, as employed for example by Riess et al. (see: 2011ApJ…730..119R).

In terms of which recent type Ia supernova was relatively nearest, the distances to the galaxies involved can be estimated based on analyzing essentially all of the redshift-independent distance estimates that have been published for galaxies since 1980, meaning in the modern era using CCDs and including observations based on NASA’s Hubble Space Telescope. Such galaxy distance estimates are tabulated in the NASA/IPAC Extragalactic Database of galaxy Distances (NED-D).

Galaxy Messier 82, the host of SN 2014J, is located at 12.0 million light-years (3.6 Megaparsecs), based on the mean of three kinds of distance indicator employing 8 different estimates. The standard deviation among those indicators is ~10%.

Galaxy NGC 5128, the host of SN 1986G, is also located at 12.0 million light-years, based on 11 different indicators employing 46 different distance estimates, and also with a standard deviation among indicators of ~10%. So, to within the precision of the indicators, both supernova occurred at essentially the same distance, confirming SN 2014J is the nearest since SN 1986G. Galaxy NGC 5253, the host of SN 1972E, is actually the nearest galaxy, at 11.0 million light-years (3.4 Megaparsecs) known to have hosted a type Ia supernova in the modern era, based on 6 indicators with 48 estimates.

M82 and Supernova 2014J imaged on January 23, 2014. Credit and copyright: Mick Hyde.

Accounting for its dimming due to the dust in Messier 82 is just one part of several involved in applying data from SN 2014J to estimate its distance. Future observations of its declining magnitude will reveal its complete light-curve. That will enable estimates to be made of its decline time and light-curve stretch factors. Once these are in hand, within the next few to several weeks at most, SN 2014J will begin its use as the nearest type Ia supernova anchor point.

More of a milestone than a Rosetta stone, SN 2014J will nevertheless have an impact of lasting legacy on future applications of type Ia supernova observations in cosmology. It will be especially significant to enhancing the use of type Ia supernova as cosmological distance indicators. That is important to ongoing projects, including the SHOES project, the Carnegie Hubble Program, and others, all of which aim to measure the Universe’s expansion rate or Hubble constant to an accuracy of better than one percent within the next decade. That level of accuracy is required in order to understand not only our Universe’s exact size and age, but also the exact Equation-of-State governing our Universe’s total energy, including its dark energy.

February 11, 2014December 29, 2015 by Susie Murph

Carnival of Space #340

This week’s Carnival of Space is hosted by our pal Ray Sanders at his Dear Astronomer blog.

Click here to read Carnival of Space #340.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space.

If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

February 11, 2014December 23, 2015 by Nancy Atkinson

A Mesmerizing Look at Year 4 of the Solar Dynamics Observatory

Coronal Mass Ejection as viewed by the Solar Dynamics Observatory on June 7, 2011. A similar type of outburst triggered aurorae during a strong geomagnetic storm in February 1872. Image Credit: NASA/SDO

Four years ago today, the Solar Dynamics Observatory embarked on a five-year mission to boldly go where no Sun-observing satellite has gone before. SDO uses its three instruments to look constantly at the Sun in ten different wavelengths. Called the “Crown Jewel” of NASA’s fleet of solar observatories, SDO is a technologically advanced spacecraft that takes images of the sun every 0.75 seconds. Each day it sends back about 1.5 terabytes of data to Earth — the equivalent of about 380 full-length movies.

SDO launched on Feb. 11, 2010, and it has since captured the amazing views of the ever-changing face of the Sun — the graceful dance of solar material coursing through the Sun’s the corona, massive solar explosions and giant sunspot shows. Enjoy this latest highlight video from year 4 from SDO!

I was priveldged to be able to attend the launch of SDO, and you can read our article about the launch here.

The launch included a little “special effects” that wowed the crowd. The Atlas rocket soared close to a sundog just as the spacecraft reached Max-Q, and a ripple effect was created around the spacecraft. You can watch the launch below to see what happened:

February 11, 2014December 23, 2015 by Elizabeth Howell

Music Video From Saturn Shows Off Dazzling Aurora Light Show

An aurora around Saturn's north pole in 2013. Credit: NASA/ESA/University of Leicester and NASA/JPL-Caltech/University of Arizona/Lancaster University

Above is the latest rave-like video from NASA. While the images are reminiscent of what could play during an awesome Friday night party, what you’re actually seeing is a timelapse of auroras on Saturn. These pictures are pretty to look at, but they also tell us more about how the sun’s belches of stuff influence the magnetic field around the ringed gas giant.

“Saturn’s auroras can be fickle — you may see fireworks, you may see nothing,” stated Jonathan Nichols of the University of Leicester in England, who led the work on the Hubble Space Telescope images shown in the video. “In 2013, we were treated to a veritable smorgasbord of dancing auroras, from steadily shining rings to super-fast bursts of light shooting across the pole.”

The light show was captured by both the Saturn-orbiting Cassini spacecraft and the Earth-orbiting Hubble. Cassini managed to nab its images from three Saturn distances away (which is apparently an unusually close vantage point.) This location “provided a look at the changing patterns of faint emissions on scales of a few hundred miles (kilometers) and tied the changes in the auroras to the fluctuating wind of charged particles blowing off the sun and flowing past Saturn,” NASA stated.

Here are a few things scientists are learning (or hoping to learn soon) from the light show:

How auroras are formed. The Cassini images suggest that as magnetic field lines forge new links, this is where the storms are centered. This process happens on Earth, so it would make sense for it to happen elsewhere. Researchers also found that some of the auroras stick close to the orbital position of Mimas, suggesting that the moon may be influencing some of the storms (a process already known to happen with Enceladus).
The nature of Saturn’s atmosphere. While the answers are still forthcoming, scientists are examining why the top of Saturn’s atmosphere (and other gas giants) are warmer than would be expected given how far they are from the sun. “By looking at these long sequences of images taken by different instruments, we can discover where the aurora heats the atmosphere as the particles dive into it and how long the cooking occurs,” stated Sarah Badman, a Cassini visual and infrared mapping spectrometer team associate at Lancaster University, England.
What color the auroras are. Red on the bottom, and purple on the top, depending on how Saturn’s hydrogen is excited and what light it emits. (For reference, Earth’s is green on bottom and red at top due to excitement of nitrogen and oxygen).
Where charged particles around Saturn go. More data from the W.M. Keck Observatory and NASA’s Infrared Telescope Facility (both in Hawaii) could show “how particles are ionized in Saturn’s upper atmosphere,” NASA stated. Better yet, scientists can compare that information to the stuff gathered from outside of Earth’s atmosphere by Hubble and Cassini. This will allow them to see what distortions the ground-based observatories experienced due to Earth’s atmosphere, and improve the accuracy of the observations.

Not bad work for a single music video, isn’t it? For more information on auroras on Saturn, check out these past Universe Today stories:

Source: NASA Jet Propulsion Laboratory

February 11, 2014December 30, 2015 by Jason Major

The Joy of Discovery, Featuring Bill Nye

“We are, you and I, at least one of the ways that the Universe knows itself.” – Bill Nye

Did you manage to (or choose to) watch the much-anticipated debate between Science Guy Bill Nye and Ken Ham on the “merits” of Creationism on Feb. 4? While clearly nothing more than a publicity event cooked up by Ham to fund his Creation Museum in Kentucky (yes, I’m afraid that’s actually a thing here in America) Nye felt it to be in his — as well as the country’s — best interest to stand up and defend science and its methods in the face of unapologetic fundamentalist denial.

The video above, just released by John D. Boswell — aka melodysheep, creator of the excellent Symphony of Science series — takes some of Bill’s statements during the debate and puts them to music and images of our fascinating world.

Continue reading “The Joy of Discovery, Featuring Bill Nye”

February 11, 2014December 23, 2015 by Shannon Hall

New Technique Puts Exoplanets on the Scale

Meet Kepler-22b, an exoplanet with an Earth-like radius in the habitable zone of its host star. Unfortunately its mass remains unknown. Image Credit: NASA

Astronomers constantly probe the skies for the unexpected. They search for unforeseen bumps in their data — signaling an unknown planet orbiting a star, a new class of astronomical objects or even a new set of physical laws that will rewrite the old ones. They are willing to embrace new ideas that may replace the wisdom of years past.

But there’s one exception to the rule: the search for Earth 2.0. Here we don’t want to find the unexpected, but the expected. We want to find a planet so similar to our own, we can almost call it home.

While, we can’t exactly image these planets with great enough detail to see if one’s a water world with luscious green plants and civilizations, we can use indirect methods to find an “Earth-like” planet — a planet with a similar mass and radius to the Earth.

There’s only one problem: the current techniques to measure an exoplanet’s mass are limited. To date astronomers measure radial velocity — tiny wobbles in a star’s orbit as it’s tugged by the gravitational pull of its exoplanet — to derive the planet-to-star mass ratio.

But given that most exoplanets are detected via their transit signal — dips in light as a planet passes in front of its host star — wouldn’t it be great if we could measure its mass based on this method alone? Well, astronomers at MIT have found a way.

Graduate student Julien de Wit and MacArthur Fellow Sara Seager have developed a new technique for determining mass by using an exoplanet’s transit signal alone. When a planet transits, the star’s light passes through a thin layer of the planet’s atmosphere, which absorbs certain wavelengths of the star’s light. Once the starlight reaches Earth it will be imprinted with the chemical fingerprints of the atmosphere’s composition.

The so-called transmission spectrum allows astronomers to study the atmospheres of these alien worlds.

But here’s the key: a more massive planet can hold on to a thicker atmosphere. So in theory, a planet’s mass could be measured based on the atmosphere, or the transmission spectrum alone.

Of course there isn’t a one to one correlation or we would have figured this out long ago. The atmosphere’s extent also depends on its temperature and the weight of its molecules. Hydrogen is so light it slips away from an atmosphere more easily than, say, oxygen.

So de Wit worked from a standard equation describing scale height — the vertical distance over which the pressure of an atmosphere decreases. The extent to which pressure drops off depends on the planet’s temperature, the planet’s gravitational force (a.k.a. mass) and the atmosphere’s density.

According to basic algebra: knowing any three of these parameters will let us solve for the fourth. Therefore the planet’s gravitational force, or mass, can be derived from its atmospheric temperature, pressure profile and density — parameters that may be obtained in a transmission spectrum alone.

With the theoretical work behind them, de Wit and Seager used the hot Jupiter HD 189733b, with an already well-established mass, as a case study. Their calculations revealed the same mass measurement (1.15 times the mass of Jupiter) as that obtained by radial velocity measurements.

This new technique will be able to characterize the mass of exoplanets based on their transit data alone. While hot Jupiters remain the main target for the new technique, de Wit and Seager aim to describe Earth-like planets in the near future. With the launch of the James Webb Space Telescope scheduled for 2018, astronomers should be able to obtain the mass of much smaller worlds.

The paper has been published in Science Magazine and is now available for download in a much longer form here.