The likely trajectory of the fireball seen on May 4, 2014 over parts of Ontario Canada. Graphic courtesy American Meteor Society.
A rare daylight meteor streaked across the skies over southern Ontario, Canada and the U.S. Northeast during the afternoon of Sunday May 4, 2014, with brightness “rivaling that of the Sun,” said the American Meteor Society. Reports of a bright fireball followed by a loud sonic boom were reported on social media, and several dashcam videos emerged showing the fireball, showing an unusual vertical trajectory.
Experts estimated the space rock that caused the excitement as being about half to one meter in diameter and exploding with a force of 50 tons of TNT energy. Canadian meteor expert Peter Brown, a professor at the University of Western Ontario said in the Winnipeg Free Press that he is confident that the fireball was large enough that some meteorite fragments may have hit the ground. .
Compared to the meteor that exploded over Chelyabinsk, Russia in February of 2013, that’s quite small. That meteor’s explosion shattered windows and injured 1,000 people.
Comparison of Lyman alpha blob observed with Cosmic Web Imager and a simulation of the cosmic web based on theoretical predictions.
Credit: Christopher Martin, Robert Hurt
- See more at: http://www.caltech.edu/content/intergalactic-medium-unveiled-caltechs-cosmic-web-imager-directly-observes-dim-matter#sthash.3bs0Xl3d.dpuf
An international team of astronomers has taken unprecedented images of intergalactic space — the diffuse and often invisible gas that connects and feeds galaxies throughout the Universe.
Until now, the structure of intergalactic space has mostly been a matter for theoretical speculation. Advanced computer simulations predict that primordial gas from the Big Bang is distributed in a vast cosmic web — a network of filaments that span galaxies and flow between them.
This vast network is impossible to see alone. In the past astronomers have looked at distant quasars — supermassive black holes at the centers of galaxies which are rapidly accreting material and shining brightly — to indicate the otherwise invisible matter along their lines of sight.
While distant quasars may reveal the otherwise invisible gas, there’s no information about how that gas is distributed across space. New images, however, from the Cosmic Web Imager are revealing the webs’ filaments directly, allowing them to be seen across space.
The first filaments observed by the Cosmic Web Imager are in the vicinity of two ancient but bright objects: the quasar QSO 1549+19 and a so-called Lyman alpha blob (yes, this is a technical term for a huge concentration of hydrogen gas) in the emerging galaxy cluster SSA22. These objects are bright, lighting up the intervening galactic space and boosting the detectable signal.
Image of quasar (QSO 1549+19) taken with Caltech’s Cosmic Web Imager, showing surrounding gas (in blue) and direction of filamentary gas inflow. Image Credit: Christopher Martin, Robert Hurt
Both objects date back to two billion years after the Big Bang, in a time of rapid star formation in galaxies. Observations show a narrow filament, about one million light-years across flowing into the quasar, which is likely fueling the growth of the host galaxy.
There are three filaments flowing into the Lyman alpha blob. “I think we’re looking at a giant protogalactic disk,” said lead author Christopher Martin from the California Institute of Technology in a press release. “It’s almost 300,000 light-years in diameter, three times the size of the Milky Way.”
The Cosmic Web Imager on board the Hale 200 inch telescope is a spectrographic imager, taking pictures at many different wavelengths simultaneously. This allows astronomers to learn about objects’ composition, mass and velocity.
“The gaseous filaments and structures we see around the quasar and the Lyman alpha blob are unusually bright,” said Martin. “Our goal is to eventually be able to see the average intergalactic medium everywhere. It’s harder, but we’ll get there.”
Europa — a moon of Jupiter first discovered by Galileo — never ceases to surprise and amaze astronomers and amateurs alike.
Last December astronomers announced water plumes erupting 100 miles high from the moon’s icy south pole. It was the best evidence yet that Europa, heated internally by the powerful tidal forces generated by Jupiter’s gravity, has a deep subsurface ocean. It caused the search for life in the outer solar system to take quite a turn.
Now, NASA has issued a Request for Information (RFI) to science and engineering communities for ideas for a mission to the enigmatic moon. Any ideas need to address fundamental questions about the subsurface ocean and the search for life beyond Earth.
“This is an opportunity to hear from those creative teams that have ideas on how we can achieve the most science at minimum cost,” said John Grunsfeld, associate administrator for the NASA Science Mission Directorate, in a press release.
The RFI’s focus is for concepts for a mission that costs less than $1 billion.
“Europa is one of the most interesting sites in our solar system in the search for life beyond Earth,” said Grunsfield. “The drive to explore Europa has stimulated not only scientific interest but also the ingenuity of engineers and scientists with innovative concepts.”
The Decadal Survey deemed a mission to Europa as an extremely high priority for scientific pursuits by NASA. It lists five key science objectives that are necessary to improve our understanding of this potentially habitable moon. Primarily, the mission will need to:
— Characterize the extent of the ocean and its relation to the deeper interior
— Characterize the ice shell and any subsurface water, including their heterogeneity, and the nature of surface-ice-ocean exchange
— Determine global surface, compositions and chemistry, especially as related to habitability
— Understand the formation of surface features, including sites of recent or current activity, identify and characterize candidate sites for future detailed exploration
— Understand Europa’s space environment and interaction with the magnetosphere.
Although Europa has been visited by spacecraft and imaged distantly by Hubble, more detailed research is necessary to understand the complexities of this moon and its potential for life. NASA’s Galileo spacecraft, launched in 1989 was the only mission to visit Europa, passing close by the moon fewer than a dozen times.
What are your ideas for a mission to the icy moon? Comment below.
Comet Jacques as imaged on March 18th, shortly after discovery. Credit: Efrain Morales Rivera.
A recently discovered comet is headed northward and is set to put on one of two fine performances for binocular observers in 2014 starting this week.
Comet C/2014 E2 Jacques was discovered on March 13th 2014 by Cristóvão Jacques, Eduardo Pimentel and João Ribeiro de Barros while observing from the Southern Observatory for Near Earth Asteroids Research (SONEAR) facility located near Oliveira, Brazil.
The comet was just about at +15th magnitude at the time of discovery as it glided across the southern hemisphere constellation of Centaurus.
While a majority of comet discoveries are destined to remain small and faint, Comet Jacques was immediately shown to be something special. Upon discovery of any new comet, the first task is to gain several observations hours or nights apart to accurately gauge its distance and orbit. Are astronomers looking at a small, garden variety comet close up, or a large, active one far away?
In the case of Comet Jacques, it was something in between: a comet about 1.22 Astronomical Units (A.U.s) distant at time of discovery. Comet Jacques is headed towards perihelion 0.66 A.U. from the Sun in early July and will pass 0.56 A.U. from Earth on August 28th. Follow up observations carried out using the iTelescope at Siding Spring Australia showed a slightly elongated coma about 2 arc minutes across shortly after discovery, and the comet has recently jumped up to magnitude +8 — ahead of the projected light curve — in just the past week.
The path of Comet Jacques, looking west from latitude 30 degree north 45 minutes after sunset. Credit: Starry Night.
We caught our first good look at Comet Jacques last night while setting up for the Virtual Star Party. While +10 magnitude or brighter is usually a pretty good rule of thumb for binocular visibility, we found that the comet was only apparent as a fuzzy smudge viewing it with a 8” Schmidt-Cassegrain telescope using averted vision at low power. Remember, the brightness of a comet is spread out over its apparent surface area, similar to viewing a diffuse nebula. Our first telescopic views of the ill-fated comet ISON as it breeched +10th magnitude were similar. Certainly, a nearby waxing crescent Moon in Gemini last night didn’t help.
How bright will Comet Jacques get? Current projections call for it to perhaps break naked eye visibility around +6th magnitude after June 1st and reach as bright as +4th magnitude in early July near perihelion. After its first evening act in May and June, Comet Jacques will reemerge in the dawn sky for northern hemisphere observers for Act 2 and trace a path northward paralleling the galactic plane through the star rich fields of Perseus, Cassiopeia, Cepheus and Cygnus in August and September of this year. If our luck holds out, Comet Jacques will remain above 6th magnitude until early September.
The path of Comet Jacques through the inner solar system. Credit: JPL solar system small body generator.
This comet also created a brief flurry of interest when it was revealed that it will pass just 0.085 AUs or 12,700,000 kilometers from Venus on July 13th, 2014. Though close, this is still 31 times the distance from Earth to the Moon. The only “eyes” that humanity has currently in operation around Venus is ESA’s Venus Express orbiter. During closest approach Comet Jacques will appear just over 3 degrees away from Venus as seen from our Earthly vantage point.
Another comet is also set to photobomb a planet, as Comet A1 Siding Spring passes a nominal distance of 0.0009 A.U.s or 135,000 kilometers from Mars this Fall on October 19th.
11 images of Comet Jacques stacked from May 3rd. Credit: Ian Griffin @IanGriffin.
The closest recorded passage of a comet near Earth was Comet D/1770 L1 Lexell in 1770, which passed us 0.015 A.U.s or 233 million kilometres distant.
Now on to Act 1. May finds Comet Jacques spending most of the month in the long rambling constellation of Monoceros. Currently moving just under 2 degrees a day, Comet Jacques crosses the celestial equator northward this week on May 8th. You’ll note its high orbital inclination of 156.4 degrees as it speeds northward. Comet Jacques has a long orbital period gauged at over 30,000 years — the last time Comet Jacques visited the inner solar system, our ancestors had the Last Glacial Maximum period to look forward to.
The projected light curve of comet Jacques with recent observations. Credit: Seiichi Yoshida/aerith.net.
Comet Jacques is currently the brightest comet “with a bullet,” edging out the +9th magnitude comets C/2012 K1 PanSTARRS gilding through Canes Venatici and comet C/2012 X1 LINEAR, currently residing in the constellation of Aquila the Eagle. A great place to keep up with current observations of comets is the Comet Observation Database. We’re also pinging the IAU Minor Planet Center’s quick look page for new discoveries daily.
Here are some highlights to watch out for as Comet Jacques heads towards perihelion. Passages within one degree — twice the size of the Full Moon — near stars brighter than +5th magnitude are noted unless mentioned otherwise:
The celestial path of Comet Jacques from May 3rd through June 1st. Credit: Starry Night.
May 8th: Passes the +4.1 magnitude star Delta Monocerotis and crosses north of the celestial equator.
May 10th: Passes planetary nebula NGC 2346.
May 11th: Passes briefly into Canis Minor before reentering the constellation Monoceros.
May 14th: Full Moon occurs, marking the start of a favorable two week period of moonless evenings soon after.
May 24th: Passes the +4.8 magnitude star 17 Monocerotis.
May 28th: New Moon occurs, marking the return of the Moon to early evening skies.
May 29th: Passes the +4.7 magnitude star 15 Monocerotis.
May 30th: Passes the Christmas tree cluster. Photo op!
May 31st: The waxing crescent Moon passes less than 8 degrees from Comet Jacques.
June 1st: Comet Jacques reaches naked eye visibility?
June 6th: Crosses into the constellation Gemini.
June 11th: Crosses into the constellation Taurus.
June 13th: Full Moon occurs.
June 14th: Crosses the galactic plane.
June 21st: Passes into the field of view of SOHO’s LASCO C3 camera.
June 27th: New Moon occurs.
July 2nd: Reaches perihelion at 0.6638 A.U. from the Sun.
July 8th: Crosses north of the ecliptic plane.
July 13th: Passes 0.085 A.U. from Venus.
August 28th: Passes 0.56 A.U. from Earth.
And thus, Comet Jacques joins the parade of fine binocular comets in the 2014 night sky, as the stage is set for Act 2 this fall. And keep in mind, the next “big one” could grace our skies at anytime… more to come!
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.
The Moon over Mexico, taken March 12, 2014 from the International Space Station by astronaut Rick Mastracchio. Credit: NASA/Rick Mastracchio.
Happy Cinco de Mayo! This beautiful image of Earth from Space was taken earlier this year, but today is a perfect day to share it. ISS astronaut Rick Mastracchio snapped this photo of the waxing gibbous Moon on March 12, 2014.
The 5th of May commemorates a victory for Mexico in the Battle of Puebla in 1862 during the Franco-Mexican War. It wasn’t an especially crucial battle, but it became a symbol of Mexican pride and a celebration of Mexican culture in the United States. Cinco de Mayo isn’t widely celebrated in Mexico, but it is celebrated by many Americans regardless of their heritage (like St. Patrick’s Day and Oktoberfest).
This photo reminds us of the fragility and beauty of our world that we all inhabit together.
Hosts: Fraser Cain and Scott Lewis
Astronomers: Gary Gonella, Andrew Dumbleton, Stuart Foreman, David Dickinson, Shahrin Ahmad and special guest Henna Khan from Bombay, India
Tonight’s Views:
the Moon’s surface
M44 Beehive Cluster
Neutron Star B224 from HST
All-Sky View
Mars with ice caps and Hellas Basin visible
Comet C/2012 K1 PanSTARRS
Stuart demonstrating how to work with software to process images
M51a Whirlpool Galaxy
M53 Globular Cluster
Rosette Nebula – NGC 2237, 2238, 2239 and 2246
Saturn
Horsehead Nebula (Barnard 33 in emission nebula IC 434) and Flame Nebula (NGC 2024) with a satellite trail
NGC 5139 Omega Centauri
M42 Orion Nebula
M63 Sunflower Galaxy
NGC 7635 Bubble Nebula
Large and Small Magellanic Clouds
We hold the Virtual Star Party every Sunday night as a live Google+ Hangout on Air. We begin the show when it gets dark on the West Coast. If you want to get a notification, make sure you circle the Virtual Star Party on Google+. You can watch on our YouTube channel or here on Universe Today.
The Eta Aquarid meteor shower is active in early May and peaks before dawn on Tuesday and Wednesday May 6-7 this year. Watch for it before the start of morning twilight in the eastern sky. Created with Stellarium
UPDATE: Watch a live webcast of the meteor shower, below, from NASA’s Marshall Space Flight Center during the night of Monday, May 5 to the early morning of May 6.
Halley’s Comet won’t be back in Earth’s vicinity until the summer of 2061, but that doesn’t mean you have to wait 47 years to see it. The comet’s offspring return this week as the annual Eta Aquarid meteor shower. Most meteor showers trace their parentage to a particular comet. The Perseids of August originate from dust strewn along the orbit of comet 109P/Swift-Tuttle, which drops by the inner solar system every 133 years after “wintering” for decades just beyond the orbit of Pluto, but the Eta Aquarids (AY-tuh ah-QWAR-ids) have the best known and arguably most famous parent of all – Halley’s Comet. Twice each year, Earth’s orbital path intersects dust and rock particles strewn by Halley during its cyclic 76-year journey from just beyond Uranus to within the orbit of Venus. When we do, the grit meets its demise in spectacular fashion as wow-inducing meteors.
Composite of Aquarid meteors from the 2012 shower. Credit: John Chumack
Meteoroids enter the atmosphere and begin to glow some 70 miles high. The majority of them range from sand to pebble sized but most no more than a gram or two. Speeds range from 25,000-160,000 mph (11-72 km/sec) with the Eta Aquarids right down the middle at 42 miles per second (68 km/sec). Most burn white though ‘burn’ doesn’t quite hit the nail on the head. While friction with the air heats the entering meteoroid, the actual meteor or bright streak is created by the speedy rock exciting atoms along its path. As the atoms return to their neutral state, they emit light. That’s what we see as meteors. Picture them as tubes of glowing gas.
The farther south you live, the higher the shower radiant will appear in the sky and the more meteors you’ll see. For southern hemisphere observers this is one of the better showers of the year with rates around 30-40 meteors per hour. With no moon to brighten the sky, viewing conditions are ideal. Except for maybe the early hour. The shower is best seen in the hour or two before the start of dawn.
The Eta Aquarid shower originates with material left behind by Halley’s Comet when the sun boils dust and ice off its nucleus around the time of perihelion. This photo from May 1986 during Halley’s last visit. Credit: Bob King
From mid-northern latitudes the radiant or point in the sky from which the meteors will appear to originate is low in the southeast before dawn. At latitude 50 degrees north the viewing window lasts about 1 1/2 hours; at 40 degrees north, it’s a little more than 2 hours. If you live in the southern U.S. you’ll have nearly 3 hours of viewing time with the radiant 35 degrees high.
A bright, earthgrazing Eta Aquarid meteor streaks across Perseus May 6, 2013. Because the radiant is low for northern hemisphere observers, watch for earthgrazers – long, bright meteors that come up from near the horizon and have long-lasting trails. Credit: Bob King
Northerners might spy 5-10 meteors per hour over the next few mornings. Face east for the best view and relax in a reclining chair. One good thing about this event – it won’t be anywhere near as cold as watching the December Geminids or January’s Quadrantids. We must be grateful whenever we can.
Meteor shower members can appear in any part of the sky, but if you trace their paths in reverse, they’ll all point back to the radiant. Other random meteors you might see are called sporadics and not related to the Eta Aquarids. Because Aquarius is home to at least two radiants, we distinguish the Etas, which radiate from near Eta Aquarii, from the Delta Aquarids, an unrelated shower active in July and August.
Wishing you clear skies and plenty of hot coffee at the ready.
According to new research, life as we know it might have emerged earlier than other intelligent life. Credit: ESO
A small galaxy circling the Milky Way may be a fossil left over from the early Universe.
The stars in the galaxy, known as Segue 1, are virtually pure with fewer heavy elements than those of any other galaxy known. Such few stars (roughly 1,000 compared to the Milky Way’s 100 billion) with such small amounts of heavy elements imply the dwarf galaxy may have stopped evolving almost 13 billion years ago.
If true, Segue 1 could offer a window into the early universe, revealing new evolutionary pathways among galaxies in the early Universe.
Only hydrogen, helium, and a small trace of lithium emerged from the Big Bang nearly 13.8 billion years ago, leaving a young universe that was virtually pure. Over time the cycle of star birth and death produced and dispersed more heavy elements (often referred to as “metals” in astronomical circles), planting the seeds necessary for rocky planets and intelligent life.
The older a star is, the less contaminated it was at birth, and the fewer metals lacing the star’s surface today. Thus the elements detectible in a star’s spectrum provide a key to understanding the generations of stars, which preceded the star’s birth.
The Sun, for example, is metal-rich, with roughly 1.4% of its mass composed of elements heavier than hydrogen and helium. It formed only 4.6 billion years ago — two thirds of the way from the Big Bang to now — and sprung from multiple generations of earlier stars.
But three stars visible in Segue 1 have an iron abundance that is roughly 3,000 times less than the Sun’s iron. Or to use the proper jargon, these three stars have metallicities below [Fe/H] = -3.5.
Researchers led by Anna Frebel of the Massachusetts Institute of Technology report that Segue 1 “may be a surviving first galaxy that experienced only one burst of star formation” in the Astrophysical Journal.
Not only do the low chemical abundances suggest this galaxy is composed of extremely old stars, but they provide tantalizing hints about the types of supernovae explosions that helped create these stars. When high-mass stars explode they disperse a mix of elements; But when low-mass stars explode they almost exclusively disperse iron.
The lack of iron suggests the stars in Segue 1 are the products of high mass stars, which explode much more quickly than low mass stars. It appears that Segue 1 underwent a rapid burst of star formation shortly after the formation of the galaxy in the early universe.
Additionally, six stars observed show some of the lowest levels of neutron-capture elements ever found, with roughly 16,000 fewer elements than those seen in the Sun. These elements are created within stars when an atomic nucleus grabs an extra neutron. So a low level indicates a lack of repeated star formation.
Segue 1 burned through its first generation of stars quickly. But after the young galaxy produced a second generation of stars it completely shut off star formation, remaining a relic of the early universe.
The findings here suggest there may be a greater diversity of evolutionary pathways among galaxies in the early universe than had previously been thought.
But before we can make any sweeping claims “we really need to find more of these systems,” said Frebel in a press release. Alternatively, “if we never find another one, it would tell us how rare it is that galaxies fail in their evolution. We just don’t know at this stage because this is the first of its kind.”
The paper will be published in the Astrophysical Journal and is available for download here.
Auroral arcs are topped by red rays light up the northeast while the moon and Jupiter shine off to the west in this photo taken last night over a small lake north of Duluth, Minn. Both moon and aurora light are reflected in puddles on the ice. Credit: Bob King
Expect the unexpected when it comes to northern lights. Last night beautifully illustrated nature’s penchant for surprise. A change in the “magnetic direction” of the wind of particles from the sun called the solar wind made all the difference. Minor chances for auroras blossomed into a spectacular, night-long storm for observers at mid-northern latitudes.
6-hours of data from NASA’s Advanced Composition Explorer spacecraft, which measures energetic particles from the sun and other sources from a spot 1.5 million kilometers ahead of Earth toward the sun. By watching the Bz graph, you’ll get advance notice of the potential for auroras. Click to visit the site. Credit: NOAA
Packaged with the sun’s wind are portions of its magnetic field. As that material – called the interplanetary magnetic field (IMF) – sweeps past Earth, it normally glides by, deflected by our protective magnetic field, and we’re no worse for the wear. But when the solar magnetic field points south – called a southward Bz – it can cancel Earth’s northward-pointing field at the point of contact, opening a portal. Once linked, the IMF dumps high-speed particles into our atmosphere to light up the sky with northern lights.
A large red patch briefly glowed above the bright green arc around 11:15 p.m. CDT last night May 3. The color was faintly visible with the naked eye. Credit: Bob King
Spiraling down magnetic field lines like firefighters on firepoles, billions of tiny solar electrons strike oxygen and nitrogen molecules in the thin air 60-125 miles up. When the excited atoms return back to their normal rest states, they shoot off niblets of green and red light that together wash the sky in multicolor arcs and rays. Early yesterday evening, the Bz plot in the ACE satellite data dipped sharply southward (above), setting the stage for a potential auroral display.
After an initial flurry of bright rays, the aurora scaled back to two bright, diffuse arcs with subtle rayed textures before erupting again around 11:30 p.m. Credit: Bob King
Nothing in the space weather forecast would have led you to believe northern lights were in the offing for mid-latitude skywatchers last night. Maybe a small possibility of a glow very low on the northern horizon. Instead we got the full-blown show. Nearly every form of aurora put in an appearance from multi-layered arcs spanning the northern sky to glowing red patches, crisp green rays and the bizarre flaming aurora. “Flames” look like waves or ripples of light rapidly fluttering from the bottom to the top of an auroral display. Absolutely unearthly in appearance and yet only 100 miles away.
VLF Auroral Chorus by Mark Dennison
I even broke out a hand-held VLF (very low frequency) radio and listened to the faint but crazy cosmic sounds of electrons diving through Earth’s magnetosphere. When my electron-jazzed brain finally hit the wall at 4 a.m., flames of moderately bright aurora still rippled across the north.
Just when you thought it was over, the whole northern sky burst into rays around 1 a.m. CDT this morning. The human eye is much more sensitive to green light than red, one of the reasons why the aurora rarely appears red except in time exposures made with a camera. Credit: Bob KingAround 2 o’clock, flames pulsed from bottom to top in patchy aurora. It’s very difficult to photograph, but here it is anyway! Credit: Bob King
So what about tonight? Just like last night, there’s only a 5% chance of a minor storm. Take a look anyway – nature always has a surprise or two up her sleeve.
