Eta Carinae, one of the most massive stars known. Credit: NASA
While the stars appear unchanging when you take a quick look at the night sky, there is so much variability out there that astronomers will be busy forever. One prominent example is Eta Carinae, a star system that erupted in the 19th century for about 20 years, becoming one of the brightest stars you could see in the night sky. It’s so volatile that it’s a high candidate for a supernova.
The two stars came again to their closest approach this month, under the watchful eye of the Chandra X-Ray Observatory. The observations are to figure out a puzzling dip in X-ray emissions from Eta Carinae that happen during every close encounter, including one observed in 2009.
The two stars orbit in a 5.5-year orbit, and even the lesser of them is massive — about 30 times the mass of the Sun. Winds are flowing rapidly from both of the stars, crashing into each other and creating a bow shock that makes the gas between the stars hotter. This is where the X-rays come from.
Here’s where things get interesting: as the stars orbit around each other, their distance changes by a factor of 20. This means that the wind crashes differently depending on how close the stars are to each other. Surprisingly, the X-rays drop off when the stars are at their closest approach, which was studied closely by Chandra when that last occurred in 2009.
Eta Carinae shines brightly in X-rays in this image from the Chandra X-Ray Observatory.
“The study suggests that part of the reason for the dip at periastron is that X-rays from the apex are blocked by the dense wind from the more massive star in Eta Carinae, or perhaps by the surface of the star itself,” a Chandra press release stated.
“Another factor responsible for the X-ray dip is that the shock wave appears to be disrupted near periastron, possibly because of faster cooling of the gas due to increased density, and/or a decrease in the strength of the companion star’s wind because of extra ultraviolet radiation from the massive star reaching it.”
More observations are needed, so researchers are eagerly looking forward to finding out what Chandra dug up in the latest observations. A research paper on this was published earlier this year in the Astrophysical Journal, which you can also read in preprint version on Arxiv. The work was led by Kenji Hamaguchi, who is with NASA’s Goddard Space Flight Center in Maryland.
A screenshot from "The Observatories", a video of mainly Australian astronomical observatories. Credit: Alex Cherney/Vimeo
Performing observations in Australia is on many astronomers’ bucket lists, and this video timelapse shows you precisely why. Famous, world-class observatories, dark sky and the beautiful desolation of the desert combine in this award-winning sequence shot by Alex Cherney and posted on Vimeo.
Cherney writes that the video “is the result of over three years of work” and was the winner of the 2014 STARMUS astrophotography competition. Here are the observatories that are featured:
Roque De Los Muchachos Observatory, La Palma;
Australian Square Kilometre Array Pathfinder, Murchison, Australia;
Australia Telescope Compact Array, Narrarbri, Australia;
In 2013, a blocking pattern over Alaska caused a record-breaking heat wave. Credit: Photo by Jesse Allen and Jeff Schmatltz, using data from theLand Processes Distributed Active Archive Center(LPDAAC) and theLANCE/EOSDIS Rapid Response
Extreme weather is becoming much more common. Heat waves and heavy rains are escalating, food crops are being damaged, human beings are being displaced due to flooding and animals are migrating toward the poles or going extinct.
Although it has been postulated that these extreme weather events may be due to climate change, a new study has found much better evidence.
The research shows blocking patterns — high-pressure systems that become immobile for days or even weeks, causing extreme heat waves and torrential rain — may have doubled in summers over the last decade.
“Since 2000, we have seen a cluster of these events,” lead author Dim Doumou told The Gaurdian earlier this month. “When these high-altitude waves become quasi-stationary, then we see more extreme weather at the surface. It is especially noticeable for heat extremes.”
It was a blocking pattern that led to the heat wave in Alaska in 2013, and to the devastating floods in Colorado last summer.
These blocking patterns are associated with the jet stream, the fast flowing winds high in Earth’s atmosphere at latitudes between 30 and 60 degrees. Sometimes the flow weakens, and the winds can dip down into more southern latitudes. These excursions lead to blocking patterns.
And the jet stream is becoming “wavier,” with steeper troughs and higher ridges.
The climatologists analyzed 35 years of wind data amassed from satellites, ships, weather stations, and meteorological balloons. They found that a warming Arctic creates and amplifies the conditions that lead to jet stream excursions, therefore raising the chances for long-duration extreme events, like droughts, floods, and heat waves.
That said the climatologists were unable to see a direct causal link between climate change and extreme weather. Ordinarily we think about “cause” in a simple sense in which one thing fully brings about another. But the Colorado floods, for example, were partially caused by moisture from the tropics, a blocking pattern, and past wildfires that increased the risk of runoff.
So there is a difference between “direct causation” and “systematic causation.” The latter is not direct, but it is no less real. In this study, the team noticed that the rise in blocking patterns correlates closely with the extra heating being delivered to the Arctic by climate change. Statistically speaking, the two seem to go hand in hand.
But the team does hypothesize a direct causal link. The jet streams are driven by the difference in temperature between the poles and the equator. So because the Arctic is warming more quickly than lower latitudes, the temperature difference is declining, providing less energy for the jet stream and causing it to meander.
Although the study shows a correlation — not causation — between more frequent blocking patterns (and therefore extreme weather) and Arctic warming, it is a solid step forward in understanding how the two are related.
The article has been published in the journal Proceedings of the National Academies of Science (PNAS).
Seeking out science and astronomy in South Carolina? You’re in luck, as we’re pleased to report the South Carolina State Museum’s brand-spanking new planetarium and astronomical observatory opened to the public earlier this month. Part of a 75,000 square foot expansion project dubbed Windows to New Worlds, the renovation puts the museum on the cutting edge of STEM education and public outreach. And not only does the new expansion include one of the largest planetariums in the southeastern U.S., but it also features the only 4D theater in the state of South Carolina. The observatory, planetarium and brand new exhibits present a fascinating blend of the grandeur of astronomical history and modern technology.
Exploring the universe… Credit: South Carolina State Museum/Sean Rayford.
“What we have built represents a quantum leap forward for South Carolina in the areas of cultural tourism, recreation and especially education,” said executive director of the South Carolina State Museum Willie Calloway in a recent press release. “Our new facility is building opportunity — opportunity for students to thrive, opportunity for our economy to grow and opportunity for our guests to be entertained in new ways.”
The 12 3/8″ refractor prior to installation in the observatory. Photo by author.
We first visited the South Carolina State Museum in 2012 when plans for the planetarium and observatory were just starting to come together. The large Alvan Clark refractor now in the observatory was on display in the main museum, but much of the telescopes in the museum’s collection of antique instruments and gear were yet to be seen by the public.
A collection of eyepieces and adapters from the Robert Ariail collection. Photo by author.
We firmly believe that a telescope out under the night sky is a happy telescope, and it’s great to see the old 12 3/8” Alvan Clark refractor in action once again!
A brass solar “flip” adapter. Photo by author.
The expansion also includes a new display for the Robert Ariail collection, a fascinating assortment of astronomical instruments dating back to 1730. A highlight of the display is a 5.6-inch refractor designed by American optician and telescope maker Henry Fitz in 1849 for Erskine College. This stands as the oldest surviving American manufactured telescope known. The Robert Ariail collection is one of the largest collections of antique refracting telescopes in the world. We were amazed at the array of old solar projectors and filters, including some that we could not immediately identify.
Just how did some of those astronomers of yore observe the Sun other than projection? In some cases, they used smoked glass… but often, we learned at our behind the scenes tour at the South Carolina State museum in Columbia that they observed the Sun through an adapter filled with dark oil. No, don’t try this inconsistent and incredibly dangerous method of solar observing at home! We also noted that several of the solar filters were cracked, which no doubt occurred while they were in use.
A “solar tube”. Note the word SUN on the side and the heat baffles in the back! Photo by author.
The Planetarium: The new planetarium is known officially as the BlueCross/BlueShield of South Carolina Planetarium, and the new 55-foot diameter digital dome seats 145 and is now running shows that cover art, science, history and — of course — astronomy. Laser light shows set to a modern rock soundtrack —cue pink Floyd’s Dark Side of the Moon, sides one and two — are also planned. And don’t miss the NASA gallery in the lobby to the planetarium which features artifacts from South Carolina hometown astronauts Frank Culbertson, Ron McNair, Charles Duke and Charles Bolden.
The Robert Ariail collection on display. Credit: The South Carolina State Museum/Brett Flashnick.
The Observatory: The Boeing Astronomical Observatory is now open for business and features the aforementioned Alvan Clark 12 3/8-inch refracting telescope. Built in 1926, this grand old refractor bespeaks of a bygone era when astronomers actually looked through telescopes, pipe in hand, atop some distant windswept mountain. Squint hard, and maybe you’ll spy a canal festooned Mars… OK, maybe that’s a stretch, but it’s amazing to look through one of these grand old instruments, in person. And the observatory is the only one of its kind in the United States (and perhaps the world) that will offer modern remote access to an antique telescope to classroom students.
The observatory exterior at night. Credit: The South Carolina State Museum/Sean Rayford.
The observatory also includes a classroom, outdoor viewing terrace, and a modern state-of-the-art computer control system that those old “astronomers of yore” only wish that they’d had, especially when they had to manually crank up the mechanical counterweights on their clock drives!
Not only is the observatory open for night viewing — and just in time for the upcoming October 8th total lunar eclipse — but they’re also open to the public for daily solar observing sessions as well. And we promise they’re utilizing the very latest in solar safety technology… no overheating oil-filled filters allowed!
The 2017 total solar eclipse and the future: But there’s another reason to visit Columbia South Carolina about three years hence: the city and the South Carolina State Museum will once again be the center of astronomical action in less than three years time, when a total solar eclipse crosses the state from the northwest to the southeast on august 21st, 2017. Towns across the United States are already preparing for this celestial spectacle, and Columbia is one of the largest cities along its path. It promises to be a great show!
Don’t miss these exciting goings on in Columbia, South Carolina… the new planetarium and observatory is truly “brighter than ever” and out of this world!
Follow the South Carolina State Museum as @SCStateMuseum and the hashtags #scsm and #BrighterThanEver.
This mosaic of images from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile shows two dramatic star formation regions in the southern Milky Way. The first of these, on the left, is dominated by the star cluster NGC 3603, located about 20 000 light-years away, in the Carina–Sagittarius spiral arm of the Milky Way galaxy. The second object, on the right, is a collection of glowing gas clouds known as NGC 3576 that lies only about half as far from Earth. Credit: ESO / G. Beccari
The universe is stunning. Images from even the most modest telescopes can unveil its brilliant beauty. But couple that with a profound reason — our ability to question and understand the physical laws that dominate that brilliant beauty — and the image transforms into something much more spectacular.
Take ESO’s latest image of two dramatic star formation regions in the southern Milky Way. John Herschel first observed the cluster on the left in 1834, during his three-year expedition to systematically survey the southern skies near Cape Town. He described it as a remarkable object and thought it might be a globular cluster. But future studies (and not to mention more dramatic images from larger telescopes) enriched our understanding, demonstrating that it was not an old globular but a young open cluster.
This chart shows the constellation of Carina and includes all the stars that can be seen with the unaided eye on a clear and dark night. The location of the open star cluster NGC 3603 is marked. This object is not spectacular in small telescopes, appearing as just a tight clump of stars surrounded by faint nebulosity. Credit: ESO
The Wide Field Imager at ESO’s La Silla Observatory in Chile recently captured the image again. The bright region on the left is the star cluster NGC 3603, located 20,000 light-years away in the Carina-Sagittarius spiral arm of the Milky Way galaxy. The bright region on the right is a collection of glowing gas clouds known as NGC 3576, located only 10,000 light-years away.
Stars are born in enormous clouds of gas and dust, largely hidden from view. But as small pockets in these clouds collapse under the pull of gravity, they become so hot they ignite nuclear fusion, and their light clears away — and brightens — the surrounding gas and dust.
Nearby regions of hydrogen gas are heated, and therefore partially ionized, by the ultraviolet radiation given off by the brilliant hot young stars. These regions, better known as HII regions, can measure several hundred light-years in diameter, and the one surrounding NGC 3603 has the distinction of being the most massive known in our galaxy.
Not only is NGC 3603 known for having the most massive HII region, it’s known for having the highest concentration of massive stars that have been discovered in our galaxy so far. At the center lies a Wolf-Rayet star system. These stars begin their lives at 20 times the mass of the Sun, but evolve quickly while shedding a considerable amount of their matter. Intense stellar winds blast the star’s surface into space at several million kilometers per hour.
Where NGC 3603 is notable for its extremes, NGC 3576 is notable for its extremities — the two huge curved objects in the outreaches of the cluster. Often described as the curled horns of a ram, these odd filaments are the result of stellar winds from the hot, young stars within the central regions of the nebula. The stars have blown the dust and gas outwards across a hundred light-years.
Additionally, the two dark silhouetted areas near the top of the nebula are known as Bok globules, dusty regions found near star formation sights. These dark clouds absorb nearby light and offer potential sites for the future formation of stars. They may further sculpt the dramatic landscape above, which is the smallest slice of our stunning universe
Screenshot of a simulation of how the universe's dark matter and gas grew in its first 13 billion years. Credit: Harvard-Smithsonian Center for Astrophysics / YouTube
How do you show off 13 billion years of cosmic growth? One way that astronomers can figure that out is through visualizations — such as this one from the Harvard-Smithsonian Center for Astrophysics, called Illustris.
Billed as the most detailed computer simulation ever of the universe (done on a fast supercomputer), you can slowly see how galaxies come alight and the structure of the universe grows. While the pictures are pretty to look at, the Kavli Foundation also argues this is good for science.
In a recent roundtable discussion, the foundation polled experts to talk about the simulation (and in particular how the gas evolves), and how watching these interaction play out before their eyes helps them come to new understandings. But like any dataset, part of the understanding comes from knowing what to focus on and why.
“I think we should look at visualization like mapmakers look at map making. A good mapmaker will be deliberate in what gets included in the map, but also in what gets left out,” said Stuart Levy, a research programmer at the National Center for Supercomputing Applications’ advanced visualization lab, in a statement.
“Visualizers think about their audience … and the specific story they want to tell. And so even with the same audience in mind, you might set up the visualization very differently to tell different stories. For example, for one story you might want to show only what it’s possible for the human eye to see, and in others you might want to show the presence of something that wouldn’t be visible in any sort of radiation at all. That can help to get a point across.”
The paths of total solar eclipses care not for political borders or conflicts, often crossing over war-torn lands.
Such was the case a century ago this week on August 21st, 1914 when a total solar eclipse crossed over Eastern Europe shortly after the outbreak of World War I.
Known as the “War to End All Wars,” — which, of course, it didn’t — World War I would introduce humanity to the horrors of modern warfare, including the introduction of armored tanks, aerial bombing and poison gas. And then there was the terror of trench warfare, with Allied and Central Powers slugging it out for years with little gain.
The path of the total solar eclipse of August 21st, 1914 laid out across modern day Europe. Credit: Google Maps/Fred Espenak/NASA/GSFC.
But ironically, the same early 20th century science that was hard at work producing mustard gas and a better machine gun was also pushing back the bounds of astronomy. Einstein’s Annus Mirabilis or “miracle year” occurred less than a decade earlier on 1905. And just a decade later in 1924, Edwin Hubble would expand our universe a million-fold with the revelation that “spiral nebulae” were in fact, island universes or galaxies in their own right.
Indeed, it’s tough to imagine that many of these discoveries are less than a century in our past. It was against this backdrop that the total solar eclipse of August 21st, 1914 crossed the eastern European front embroiled in conflict.
Solar eclipses have graced the field of battle before. An annular solar eclipse occurred during the Battle of Isandlwana in 1879 during the Zulu Wars, and a total solar eclipse in 585 B.C. during the Battle of Thales actually stopped the fighting between the Lydians and the Medes.
A photograph of an “eclipse camp” in the Crimea in 1914. Credit: University of Cambridge DSpace.
But unfortunately, no celestial spectacle, however grand, would save Europe from the conflagration war. In fact, several British eclipse expeditions were already en route to parts of Russia, the Baltic, and Crimea when the war broke out less than two months prior to the eclipse with the assassination of Archduke Ferdinand on June 28th, 1914. Teams arrived to a Russia already mobilized for war, and Britain followed suit on August 4th, 1914 and entered the war when Germany invaded Belgium.
You can see an ominous depiction of the path of totality from a newspaper of the day, provided from the collection of Michael Zeiler:
An illustration of the 1914 total solar eclipse “scorching” a war-ravaged Europe. Credit: From the collection of Michael Zeiler. Used with permission.
Note that the graphic depicts a Europe aflame and adds in the foreboding description of Omen faustum, inferring that the eclipse might be an “auspicious omen…” eclipses have never shaken their superstitious trappings in the eyes of man, which persists even with today’s fears of a “Blood Moon.”
A race was also afoot against the wartime backdrop to get an expedition to a solar eclipse to prove or disprove Einstein’s newly minted theory of general relativity. One testable prediction of this theory is that gravity bends light, and astronomers soon realized that the best time to catch this in action would be to measure the position of a star near the limb of the Sun — the most massive light bending object in our solar system — during a total solar eclipse. The advent of World War I would scrub attempts to observe this effect during the 1914 and 1916 eclipses over Europe.
An expedition led by astronomer Arthur Eddington to observe an eclipse from the island of Principe off of the western coast of Africa in 1919 declared success in observing this tiny deflection, measuring in less than two seconds of arc. And it was thus that a British expedition vindicated a German physicist in the aftermath of the most destructive war up to that date.
The total solar eclipse of August 21st 1914 was a member of saros cycle 124, and was eclipse number 49 of 73 in that particular series. Eclipses in the same saros come back around to nearly the same circumstances once every triple saros period of 3 times 18 years and 11.3 days, or about every 54+ years, and there was an eclipse with similar circumstances slightly east of the 1914 eclipse in 1968 — the last total eclipse of saros 124 — and a partial eclipse from the same saros will occur again on October 25th, 2022.
All historical evidence we’ve been able to track down suggests that observers that did make it into the path of totality were clouded out at show time, or at very least, no images of the August 21st 1914 eclipse exist today. Can any astute reader prove us wrong? We’d love to see some images of this historical eclipse unearthed!
A simulation of the total solar eclipse of August 21st 1914 as seen from Latvia. Created using Starry Night Education software.
And, as with all things eclipse related, the biggest question is always: when’s the next one? Well, we’ve got another of total lunar eclipse coming right up on October 8th, 2014, again favoring North America. The next total solar eclipse occurs on March 20th, 2015 but is only visible along a path covering the Faroe and Svalbard Islands, with a path crossing the Norwegian Sea.
But, by happy coincidence, we’re also only now three years out this week from the total solar eclipse of August 21st, 2017 that spans the contiguous “Lower 48” of the United States. The shadow of the Moon will race from the northwest and make landfall off of the Pacific coast of Oregon before reaching a maximum duration for totality at 2 minutes and 40 seconds across Missouri, southern Illinois and Kentucky and will then head towards the southeastern U.S. to depart land off of the coast of South Carolina. Millions will witness this event, and it will be the first total solar eclipse for many. A total solar eclipse hasn’t crossed the contiguous United States since 1979, so you could say that we’re “due”!
The path of the 2017 total solar eclipse across the United States. Credit: Eclipse-Maps.
Already, towns in Kentucky to Nebraska have laid plans to host this event. The eclipse occurs towards the afternoon for residents of the eastern U.S., which typically sees afternoon thunderstorms popping up in the sultry August summer heat. Eclipse cartographer Michael Zeiler states that the best strategy for eclipse chasers three years hence is to “go west, young man…”
It’s fascinating to ponder tales of eclipses past, present, and future and the role that they play in human history… where will you be on August 21st, 2017?
The small fuzzy potential comet is at center in this photo taken discovered by Terry Lovejoy. Credit: copyright Alain Maury and Joaquin Fabrega
It’s confirmed! Australian amateur astronomer Terry Lovejoy just discovered his fifth comet, C/2014 Q2 (Lovejoy). He found it August 17th using a Celestron C8 fitted with a CCD camera at his roll-off roof observatory in Brisbane, Australia.
Image triplet taken by Terry Lovejoy of his comet discovery. The comet moves slightly counterclockwise around the larger fuzzy spot over the time frame. Credit: Terry Lovejoy
“I take large sets of image triplets, i.e 3 images per star field and use software to find moving objects,” said Lovejoy. “The software I use outputs suspects that I check manually by eye.”
Most of what pops up on the camera are asteroids, known comets, or false alarms but not this time. Lovejoy’s latest find is a faint, fuzzy object in the constellation Puppis in the morning sky.
Sky as seen from central South America showing the approximate location of the new comet (purple circle) on August 19 in Puppis near the bright star Canopus. The view shows the sky facing southeast just before the start of dawn. Stellarium
Glowing a dim magnitude +15, the new comet will be a southern sky object until later this fall when it swings quickly northward soon around the time of perihelion or closest approach to the sun. Lovejoy’s find needs more observations to better refine its orbit, but based on preliminary data, Maik Meyer, founder of the Comets Mailing List, calculates a January 2, 2015 perihelion.
Another photo of C/2014 Q2 taken on August 19, 2014. Credit: Jean-François and Alain Maury
On that date, it will be a healthy 84 million miles from the sun, but one month earlier on December 7, the comet could pass just 6.5 million miles from Earth and be well placed for viewing in amateur telescopes.
Everything’s still a little up in the air right now, so these times and distances are likely to change as fresh observations pour in. Take all predictions with a major grain of salt for the moment.
Comet Lovejoy (C/2011 W3) photographed by NASA astronaut Dan Burbank, onboard the International Space Station on Dec. 22, 2011 from 250 miles up. Credit: NASA
You might remember some of Terry’s earlier comets. Comet Lovejoy (C/2011 W3), a Kreutz sungrazer discovered in November 2011, passed just 87,000 miles above the sun’s surface. Many astronomers thought it wouldn’t survive the sun’s heat, yet amazingly, although much of its nucleus burned off, enough material survived to produce a spectacular tail.
Terry Lovejoy
More recently, Comet Lovejoy (C/2013 R1) thrilled observers as it climbed to naked eye brightness last November, managing to do the impossible at the time and draw our eyes away from Comet ISON.
Congratulations Terry on your new find! May it wax brightly this fall.
* Update: The latest orbit calculation from the Minor Planet Center based on 24 observations now puts perihelion at 164.6 million miles (265 million km) on February 14, 2015. Closest approach to Earth of 93.2 million miles (150 million km) will occur in January.
End of flight fragmentation of the Nov. 18, 2012, fireball over the San Francisco Bay Area (shown in a horizontally mirrored image to depict the time series from left to right). The photographs were taken from a distance of about 40 miles (65 km). Image Credit: Robert P. Moreno Jr., Jim Albers and Peter Jenniskens
What’s the chance of that thump you just heard in your house was a meteorite hitting your roof? That was the case for one family in Novato, California during a fireball event that took place in the north bay area near San Francisco on October 17, 2012.
Researchers have now released new results from analysis of the meteor that fell to Earth, revealing that the “Novato meteorite” was part of numerous collisions over a span of 4 billion years.
There is nothing ordinary about a meteorite whether it just spent 4.4 billion years all alone or spent such time in a game of cosmic pinball, interacting with other small or large bodies of our Solar System. On any given night one can watch at least a couple of meteors overhead burning up, lighting up the sky but never reaching the Earth below. However, in less than two years, Dr. Peter Jenniskens, SETI Institute’s renowned meteor expert was effectively host to two meteorites within a couple hours drive from his office in Mountain View, California.
The first was the Sutter Mill meteorite, a fantastic carbonaceous chondrite full of organic compounds. The second was the Novato meteorite, identified as a L6 chondrite fragmental breccia. which is the focus of new analysis, to be released in a paper in the August issue of Meteoritics and Planetary Science. Early on, it was clear that this meteorite had been a part of a larger asteroidal parent body that had undergone impact shocks.
Analysis of the meteorite was spearheaded by Jenniskens who initially determined the trajectory and orbit of the meteoroid from the Cameras for Allsky Meteor Surveillance (CAMS) which he helped establish in the greater San Francisco bay area. Jenniskens immediately released information about the fireball to local news agencies to ask for the public’s help with the hopes of finding pieces of the meteorite. One resident recalled hearing something hit her roof, and with the help of neighbors, they investigated and soon found the first fragment in their backyard.
Finding fragments was the first step, and over a two year period, the analysis of the Novato meteorite was spread across several laboratories around the world with specific specialties.
Novato N04, found by Bob Verish. The fourth of six fragments of the Novato fireball recovered. Fusion crust from entry into the Earth’s atmosphere is clearly evident. A 1 centimeter cube is shown for size comparison. (Image Credit, B. Verish, cams.seti.org)
Dr. Jenniskens, along with 50 co-authors, have concluded that the Novato meteorite had been involved in more impacts than previously thought. Dr. Qingzhu Yin, professor in the Department of Earth and Planetary Sciences at the University of California, Davis stated, “We determined that the meteorite likely got its black appearance from massive impact shocks causing a collisional resetting event 4.472 billion years ago, roughly 64-126 million years after the formation of the solar system.”
The predominant theory of the Moon’s formation involves an impact of the Earth by a Mars-sized body. The event resulted in the formation of the Moon but also the dispersal of many fragments throughout the inner Solar System. Dr. Qingzhu Yin continued, “We now suspect that the moon-forming impact may have scattered debris all over the inner solar system and hit the parent body of the Novato meteorite.”
Additionally, the researcher discovered that the parent body of the Novato meteorite experienced a massive impact event approximately 470 million years ago. This event dispersed many asteroidal fragments throughout the Asteroid Belt including a fragment from which resulted the Novato meteorite.
The Novato meteorite strewn field determined by Dr. Jenniskens team’s analysis of CAMS allsky images. (Illustration Credit, P. Jenniskens, NASA, SETI – cams.seti.org)
The trajectory analysis completed earlier by Dr. Jenniskens pointed the Novato meteorite back to the Gefion asteroid family. Dr. Kees Welten, cosmochemist at UC Berkeley, was able to further pinpoint the time, drawing the conclusion, “Novato broke from one of the Gefion family asteroids nine million years ago.” His colleague at Berkeley, cosmochemist Dr. Kunihiko Nishiizumialso added, “but may have been buried in a larger object until about one million years ago.”
There was more that could be revealed about history of the Novato meteorite. Dr. Derek Sears a meteoriticist working for the Bay Area Environmental Research Institute in Sonoma, California and stationed at NASA Ames Reserach Center applied his expertise in thermoluminescence. Dr. Sears was involved in the analysis of Lunar regolith returned by the Apollo astronauts using this analysis method.
“We can tell the rock was heated, but the cause of the heating is unclear,” said Dr. Sears, “It seems that Novato was hit again.” As stated in the NASA press release, “Scientists at Ames measured the meteorites’ thermoluminescence – the light re-emitted when heating of the material and releasing the stored energy of past electromagnetic and ionizing radiation exposure – to determine that Novato may have had another collision less than 100,000 years ago.”
From this apparent final collision one hundred thousand years ago, the Novato meteoroid completed over 10,000 orbits of the Sun and with its final Solar orbit, intercepted the Earth, entering our atmosphere and mostly burning up over California. The meteoroid is estimated to have measured 14 inches across (35 cm) and have weighed 176 pounds (80 kg). What reached the ground likely amounted to less than 5 lbs. (~ 2 kg). Only six fragments were recovered and many more remain buried or hidden in Sonoma and Napa counties.
Besides the analysis that revealed the series of likely impact events in the meteoroids history, a team led by Dr. Dan Glavin from NASA Goddard Space Flight Center undertook analysis in search of amino acids, the building blocks of life. They detected non-protein amino acids in the meteorite that are very rare on Earth. Dr. Jenniskens emphasized that the quick recovery of the fragments by scores of individuals that searched provided pristine samples for analysis.
The impact dent on the rooftop of the Webber home in Novato. Luis Rivera points to the dent. (Image Credit, P.Jenniskens, L.Rivera, cams.seti.org)
Robert P. Moreno, Jr. in Santa Rosa, CA photographed the fireball in greatest detail with a high resolution camera. Several other photos were brought forward from other vantage points. Dr. Jenniskens stated, “These photographs show that this meteorite – now one of the best studied meteorites of its kind – broke in spurts, each time creating a flash of light as it entered Earth’s atmosphere.”
An animated gif of the series of photographs taken by Robert Moreno Jr. Click on the image to animate in full resolution. (Credit, R. Moreno Jr., NASA, SETI)
Numerous individuals and groups undertook the search for the Novato meteorite. Dr. Jenniskens trajectory analysis included a likely impact zone or strewn field. People from all walks of life roamed the streets, open fields and hillsides of the north bay in search of fragments. Despite organized searches by Dr. Jenniskens, it was the footwork from other individuals that led to finding six fragments and was the first step which led to these studies that add to the understanding of the early Solar System’s development.
For Dr. Jenniskens, Novato was part of a trifecta – the April 22, 2012, Sutter Mill meteorite in the nearby foothills of the Sierras, the Novato meteorite and the massive Chelyabinsk airburst event in Russia on February 15, 2013. Throughout this period, Dr. Jenniskens all-sky camera network continued to expand and record “falling stars” – meteors. The number of meteors recorded with calculated trajectories is now over 175,000. The SETI Institute researcher has been supported by NASA and personnel at the institute and ordinary citizens including amateur astronomers that have refined the methods for meteor orbital determination and estimating their size and mass. Several websites have compiled images and results for the Novato meteorite with Dr. Jenniskens’ – CAMS.SETI.ORG being most prominent.
Astronomers are gazing closely at supernova 2014J (inset) to see what sort of triggers caused the star explosion. Credit: NASA/SAO/CXC/R. Margutti et al
X marks the spot: after probing the area where a star used to be, in X-rays, astronomers have been able to rule out one cause for the supernova explosion.
Because the Chandra X-Ray Observatory did not detect anything unusual in X-rays, astronomers say this means that a white dwarf was not responsible for pulling off material from a massive star that exploded (from Earth’s vantage point) on Jan. 21, 2014, triggering excitement from professional and amateur astronomers alike.
“While it may sound a bit odd, we actually learned a great deal about this supernova by detecting absolutely nothing,” stated study leader Raffaella Margutti of the Harvard-Smithsonian Center for Astrophysics (CfA) in Massachusetts. “Now we can essentially rule out that the explosion was caused by a white dwarf continuously pulling material from a companion star.”
So what caused it? Possibly two white dwarfs merged instead. Follow-up observations will take place in Messier 88 and the source of the explosion, which was about 12 million light-years from Earth. While that’s a long time by human standards, astronomers point out that is close on the cosmic distance scale.
