An image of the surface of comet 67P/Churyumov-Gerasimenko worth a thousand words
Space news (solar system science: planetary science; cometary science) – 66 feet above the surface of comet 67P/Churyumov-Gerasimenko; in a controlled descent –
The image above is the last thing the OSIRIS narrow-angle camera aboard the European Space Agency”s (ESA)Rosetta spacecraft captured before it hit the surface of comet 67P/Churyumov-Gerasimenko at 4:19 a.m. PDT (7:19 a.m. EDT/1:19 p.m. CEST) on September 30, 2016. During this controlled crash landing of the first spacecraft in history to rendezvous and escort a comet as it orbits the Sun. Astronomers were able to conduct an additional study of the gas, dust and plasma environment close to the surface of the comet and take these high-resolution images.
The OSIRIS narrow-angle camera also captured the image shown at the top of the page from a height of around 10 miles (16 kilometers) from the surface of comet 67P/Churyumov-Gerasimenko. This image spans a distance of around 2,000 feet (614 meters) across the comet’s icy and volatile surface. Attempting to walk across such a surface as Bruce Willis and his drilling crew did in the movie Armageddon is going to be tricky at best.
It might seem like a waste to purposely crash the Rosetta spacecraft on comet 67P/Churyumov-Gerasimenko, but in the end, it’s probably the best solution. This comets headed out beyond the orbit of Jupiter, which is further from the Sun than the spacecraft has traveled before, and there wouldn’t be enough solar power to operate its systems. Communicating with the spacecraft’s also about to become difficult for a month, with the Sun being close to the line-of-sight between Earth and Rosetta during this time period.
Rosetta mission complete
Feel happy for Rosetta and team, they both did the job, and then some in the end. It took a decade of careful planning and travel to rendezvous with comet 67P/Churyumov-Gerasimenko and write history. Just one month and two days later, a smaller lander named Philae touched down on the surface of the comet. It bounced on the surface a few times, before finally setting down. During the next few days, it took the first images ever of a comet’s surface up close and sent back important data planetary scientists will use to look for clues to the role comets played in the formation of the planets 4.5 billion years ago. Clues they hope to use to learn more about the origin and evolution of our solar system and possibly the formation of solar systems in general.
Expelled outer layers of white dwarf glowing brightly in the infrared
Space news (astrophysics: planetary nebula; Helix Nebula) – 650 light-years from Earth toward the constellation Aquarius –
This composite image shows a visually stunning planetary nebula labeled “The Eye of God” more serious observers call the Helix Nebula (NGC 7293). Planetary nebula are the remains of a dying star much like our own Sol, only 5 billion years in the future. At this time the Sun will run out of hydrogen to use as its fuel source for the fusion process and will start using helium to create heavier carbon, nitrogen, and oxygen. Once it runs out of helium to fuse, it will die and expel its outer gas layers, leaving a tiny, hot core called a white dwarf. An Earth-sized core so dense a teaspoon full would weigh more than a few black rhinos.
First discovered in the 18th century, planetary nebula like the Helix Nebula emit across a similar, broad spectrum from ultraviolet to infrared. The image shown at the top uses a combination of ultraviolet radiation collected by NASA’s Galaxy Evolution Explorer ((GALEX in blue(0.15 to 2.3 microns)) and infrared light detected by their Spitzer Space Telescope ((red(8 to 24 microns) and green(3.6 to 4.5 microns)) and Wide-field Infrared Survey Explorer ((WISE in red(3.4 to 4.5 microns)) showing the subtle differences observed in the different wavelengths of light emitted by ghostly celestial objects like NGC 7293 and NGC 6369 (The Little Ghost).
Astronomers have studied planetary nebulae like the Helix Nebula and M2-9 (Wings of a Butterfly Nebula) as much as any recorded during the human journey to the beginning of space and time. The remnant of a rapidly evolving star near the end of its lifespan, the white dwarf star is a tiny, barely perceptible point of light at the center of the nebula in this composite image. Thousands of planetary nebula have been detected within a distance of about 100 million light-years of Earth and astronomers estimate about 10,000 exist in the Milky Way. Making planetary nebula a relatively common celestial mystery observed as we trace our roots to their beginning.
Heralding the growth of monster black holes pulling in surrounding material while belching out the cosmic x-ray background
Space news (astrophysics: x-ray bursts; detecting high-energy x-rays emitted by supermassive black holes) – searching the COSMOS field for elusive, high-energy x-rays with a high-pitched voice –
Astronomers searching for elusive, high-energy x-rays emitted by supermassive black holes recently made a discovery using NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR). A chorus of high-energy x-rays emitted by millions of supermassive black holes hidden within the cores of galaxies spread across a field of galaxies called the COSMOS field. Singing the elusive, high-pitched song of a phenomenon scientists call the cosmic x-ray background they emitted when they pulled surrounding matter closer. A significant step in resolving the high-energy x-ray background and understanding more about the feeding habits of supermassive black holes as they grow and evolve.
“We’ve gone from resolving just two percent of the high-energy X-ray background to 35 percent,” said Fiona Harrison, the principal investigator of NuSTAR at Caltech in Pasadena and lead author of a new study describing the findings in an upcoming issue of The Astrophysical Journal. “We can see the most obscured black holes, hidden in thick gas and dust.”
The Monster of the Milky Way, the supermassive black hole believed to reside at the core of our galaxy, bulked up by siphoning off surrounding gas and dust in the past and will continue to grow. The data obtained here by NASA’s NuSTAR will help scientists learn more concerning the growth and evolution of black holes and our host galaxy. It will also give astrophysicists more insight into the processes involved the next time the Monster of the Milky Way wakes up and decides to have a little snack.
“Before NuSTAR, the X-ray background in high energies was just one blur with no resolved sources,” said Harrison. “To untangle what’s going on, you have to pinpoint and count up the individual sources of the X-rays.”
NASA’s NuSTAR’s the first telescope capable of focusing high-energy x-rays into a sharp image, but it only gives us part of the picture. Additional research’s required to clear up the picture a little more and give us a better view of the real singers in the choir. NuSTAR should allow astronomers to decipher individual voices of x-ray singers in one of the cosmos’ rowdiest choirs.
“We knew this cosmic choir had a strong high-pitched component, but we still don’t know if it comes from a lot of smaller, quiet singers, or a few with loud voices,” said co-author Daniel Stern, the project scientist for NuSTAR at NASA’s Jet Propulsion Laboratory in Pasadena, California. “Now, thanks to NuSTAR, we’re gaining a better understanding of the black holes and starting to address these questions.”
Astronomers plan on collecting more data on the high-energy x-ray choir of the COSMOS field, which should help clear up a few mysteries surrounding the birth, growth, and evolution of black holes. Hopefully, it gives also gives us more clues to many of the mysteries we discover during the human journey to the beginning of space and time.
Produces shocks that accelerate particles, illuminating the colliding material
Space news (astrophysics: relativistic jets; shock collisions inside particle jets) – Observing plasma jet blasting from supermassive black hole in core of galaxy NGC 3862, 260 million light-years from Earth toward the constellation Leo in the rich galaxy cluster Abell 1367 –
Astronomers recently made an interesting discovery while studying data collected by the Hubble Space Telescope over two decades of observing the core of elliptical galaxy NGC 3862. They were originally looking to create a time-lapse video of a relativistic jet blasting from the supermassive black hole thought to reside within its core. Instead, they discovered a rear-end collision between two separate high-speed waves of material ejected by a monster black hole whose mass astronomers have yet to measure. In this case, scientists believe the rear-end collision accelerated and heated particles which illuminated the colliding material for Hubble to see.
The relativistic jet erupting from the accretion disk of the supermassive black hole thought to reside at the core of galaxy NGC 3862 is one of the most studied and therefore best understood. It’s also one of the few active galaxies with jets observed in visible light. It appears to stream out of the accretion disk at speeds several times the speed of light, but this is just a visual illusion referred to as superluminal motion created by the combination of insanely fast velocities and our line of sight being almost on point. It forms a narrow beam hundreds of light-years in length that eventually begins to spread out like a cone, before forming clumps at around 1,000 light-years. Clumps scientists study looking for clues pointing to facts they can use to learn more about these plasma jets and the cosmos.
Astronomers have observed knots of material being ejected from dense stellar objects previously during the human journey to the beginning of space and time. This is one of the few times they have detected knots with an optical telescope thousands of light-years from a supermassive black hole. It’s the certainly the first time we have detected a rear-end collision between separately ejected knots in a relativistic jet.
“Something like this has never been seen before in an extragalactic jet,” said Eileen Meyer of NASA’s Space Telescope Science Institute (STScI). “As the knots continue merging they will brighten further in the coming decades. This will allow us a very rare opportunity to see how the energy of the collision is dissipated into radiation.”
What would cause successive jets of material to achieve varying speeds? One theory involves the idea of material falling onto the supermassive black hole being superheated and ejected along its spin axis. Ejected material is constrained by the powerful magnetic fields surrounding the monster black hole into a narrow beam. If the flow of falling material isn’t perfectly smooth, knots are ejected in a string, rather than a continuous beam or steady hose.
It’s possible knots ejected later travel through a less dense interstellar medium, which would result in varying speeds. In this scenario, a knot launched after another knot would eventually catch up and rear-end it.
Beyond learning knots of material ejected in plasma jets erupting from the accretion disk of a supermassive black hole sometimes rear-end each other, astronomers are interested in this second case of superluminal motion observed in jets hundreds, thousands of light-years from the source supermassive black hole. This indicates the jets are still moving at nearly the speed of light at distances rivaling the scale of the host galaxy and still contain tremendous energy. Understanding this could help astronomers determine more about the evolution of galaxies as the cosmos ages, including our own Milky Way.
Astronomers are also trying to figure out why galaxy NGC 3862 is one of the few they have detected jets in optical wavelengths? They haven’t been able to come up with any good theories on why some jets are detected in visible light and others aren’t.
Work goes on
Work at the institute continues. Meyer is currently working on additional videos using Hubble images of other relativistic jets in nearby galaxies to try to detect superluminal motion. This is only possible due to the longevity of the Hubble Space Telescope and ingenuity of engineers and scientists from NASA and the ESA. Hopefully, they could discover more clues to answer these questions and other mysteries gnawing at the corner of my mind.
Can blow star-forming gas 1000 light-years out of core region of host galaxies
Space news (astrophysics: evolution of galaxies; feedback mechanisms) – about 2.3 billion years ago in a galaxy far, far away and standing in a fierce, 2 million mile per hour (3 million kilometers per hour) outflow of star-forming gas –
Astrophysicists studying the evolution of galaxies using the Suzaku X-ray satellite and the European Space Agency’s Herschel Infrared Space Observatory have found evidence suggesting supermassive black holes significantly influence the evolution of their host galaxies. They found data pointing to winds near a monster black hole blowing star-forming gas over 1,000 light-years from the galaxy center. Enough material to form around 800 stars with the mass of our own Sol.
“This is the first study directly connecting a galaxy’s actively ‘feeding’ black hole to features found at much larger physical scales,” said lead researcher Francesco Tombesi, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland, College Park (UMCP). “We detect the wind arising from the luminous disk of gas very close to the black hole, and we show that it’s responsible for blowing star-forming gas out of the galaxy’s central regions.”
The artist’s view of galaxy IRAS F11119+3257 (F11119) above shows 3 million miles per hour winds produced near the supermassive black hole at its center heating and dispersing cold, dense molecular clouds that could form new stars. Astronomers believe these winds are part of a feedback mechanism that blows star-forming gas from galaxy centers, forever altering the structure and evolution of their host galaxy.
Astronomers have been studying the Monster of the Milky Way, the supermassive black hole with an estimated mass six million times that of Sol thought to reside at the center of our galaxy, for years. The monster black hole at the core of F11119 is thought to contain around 16 million times the mass of Sol. The accretion disk surrounding this supermassive black hole is measured at hundreds of times the diameter of our solar system. The 170 million miles per hour (270 million kilometers per hour) winds emanating from its accretion disk push the star-forming dust out of the central regions of the galaxy. Producing a steady flow of cold gas over a thousand light-years across traveling at around 2 million mph (3 million kph) and moving a volume of mass equal to around 800 Suns.
Astrophysicists have been searching for clues to a possible correlation between the masses of a galaxy’s central supermassive black hole and its galactic bulge. They have observed galaxies with more massive black holes generally, have bulges with proportionately larger stellar mass. The steady flow of material out of the central regions of galaxy F11119 and into the galactic bulge could help explain this correlation.
“These connections suggested the black hole was providing some form of feedback that modulated star formation in the wider galaxy, but it was difficult to see how,” said team member Sylvain Veilleux, an astronomy professor at UMCP. “With the discovery of powerful molecular outflows of cold gas in galaxies with active black holes, we began to uncover the connection.”
“The black hole is ingesting gas as fast as it can and is tremendously heating the accretion disk, allowing it to produce about 80 percent of the energy this galaxy emits,” said co-author MarcioMeléndez, a research associate at UMCP. “But the disk is so luminous some of the gas accelerates away from it, creating the X-ray wind we observe.”
When the supermassive black hole’s most active, it clears cold gas and dust from the center of the galaxy and shuts down star formation in this region. It also allows shorter-wavelength light to escape from the accretion disk of the black hole astronomers can study to learn more. We’ll keep you updated on any additional discoveries.
What’s the conclusion?
Astrophysicists conclude F11119 could be an early evolutionary phase of a quasar, a type of active galactic nuclei (AGN) with extreme emissions across a broad spectrum. Computer simulations show the supermassive black hole should eventually consume the gas and dust in its accretion disk and then its activity should lessen. Leaving a less active galaxy with little gas and a comparatively low level of star formation.
Astrophysicists and scientists look forward to detecting and studying feedback mechanisms connected with the growth and evolution of supermassive black holes using the enhanced ability of ASTRO-H. A joint space partnership between Japan’s Aerospace Exploration Agency (ISAS/JAXA) and NASA’s Goddard Space Flight Center, Suzaku’s successors expected to lift the veil surrounding this mystery even more and lay the foundation for one day understanding a little more about the universe and its mysteries.
Watch an animation made by NASA’s Goddard Space Flight Center showing how black hole feedback works in quasars here.
Data shows at least one of two exoplanets studied orbits within the habitable zone of host red dwarf star in system TRAPPIST-1
Space news (the search for Earth 2.0: the first atmospheric study of Earth-sized exoplanets; TRAPPIST-1 system) – searching for possible atmospheres surrounding exoplanets TRAPPIST-1b and TRAPPIST-1c 40 light-years from Earth toward the constellation Aquarius –
Astronomers using the Hubble Space Telescope to search for suitable exoplanets to act as a cradle for a new human genesis recently sampled the atmospheres of two exoplanets orbiting a red dwarf star 40 light-years from Earth. They used Hubble’s Wide Field Camera 3 to observe TRAPPIST-1b and TRAPPIST-1c in near-infrared wavelengths to look for signs of an atmosphere. They discovered these two exoplanets probably don’t have the fluffy, hydrogen-dominated atmospheres found around larger, gaseous exoplanets.
The image seen at the top of the page is an artist’s portrayal of TRAPPIST-1b and 1c, two Earth-sized exoplanets shown passing in front of their host red dwarf star. Astronomers used the Hubble Space Telescope to look for hints of atmospheres surrounding these distant worlds and detected signs increasing the chances of habitability.
“The lack of a smothering hydrogen-helium envelope increases the chances for habitability on these planets,” said team member Nikole Lewis of the Space Telescope Science Institute (STScI) in Baltimore. “If they had a significant hydrogen-helium envelope, there is no chance that either one of them could potentially support life because the dense atmosphere would act like a greenhouse.”
Julien de Wit of the Massachusetts Institute of Technology in Cambridge and a team of astronomers used spectroscopy to decipher the light, revealing clues to the chemical composition of an atmosphere surrounding these candidates. By taking advantage of a rare double-transit of both exoplanets across the face of their host star, they collected starlight passing through any gas envelope surrounding these exoplanets. This event only occurs every two years, but it allowed for a simultaneous measurement of atmospheric characteristics. The exact composition’s still a mystery at this point, further observations are required to determine more clues. This is an exciting and promising start.
“These initial Hubble observations are a promising first step in learning more about these nearby worlds, whether they could be rocky like Earth, and whether they could sustain life,” says Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “This is an exciting time for NASA and exoplanet research.”
Estimates put the age of the host red dwarf star at around 500 million years, which is young for a star with a potential lifespan of trillions of years. Red dwarf stars burn a lot cooler, but completely consume their supply of hydrogen, unlike more massive types of stars. The most common star in the cosmos, astronomers think 20 out of 30 near-Earth suns could be red dwarfs. The numbers indicate searching nearby red dwarfs for an exoplanet with the right ingredients for habitability is a good place to begin our search.
The team and other astronomers plan on making follow-up measurements of these two exoplanets using the Hubble Space Telescope, the Kepler Space Telescope, the TRAPPIST telescope at ESO’s La Silla Observatory, and other assets to look for thinner gas layers containing heavier atoms than hydrogen as in Earth’s atmosphere.
“With more data, we could perhaps detect methane or see water features in the atmospheres, which would give us estimates of the depth of the atmospheres,” said Hannah Wakeford, the paper’s second author, at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Toward the future
In the years ahead, using assets like NASA’s James Webb Space Telescope, astronomers should be able to determine the exact composition of any atmospheres surrounding these exoplanets and others. Finding the signatures of water vapor and methane, or even carbon dioxide and ozone is a significant step toward possible habitability for lifeforms. The power of Webb should also allow planetary scientists to measure the surface and atmospheric temperature and pressure of each exoplanet. Both key factors to determining if these exoplanets orbiting red dwarf TRAPPIST-1 are possible cradles for the genesis of life.
“Thanks to several giant telescopes currently under construction, including ESO’s E-ELT and the NASA/ESA/CSA James Webb Space Telescope due to launch for 2018, we will soon be able to study the atmospheric composition of these planets and to explore them first for water, then for traces of biological activity. That’s a giant step in the search for life in the Universe,” says Julien de Wit.
“These Earth-sized planets are the first worlds that astronomers can study in detail with current and planned telescopes to determine whether they are suitable for life,” said de Wit. “Hubble has the facility to play the central atmospheric pre-screening role to tell astronomers which of these Earth-sized planets are prime candidates for more detailed study with the Webb telescope.”
Hypernova SN 2006gy was over a hundred times brighter than a typical supernova
Space news (astrophysics: hypernovae; one of the brightest ever, SN 2006gy) – 240 million light-years toward the constellation Perseus in galaxy NGC 1260 –
It all started in September of 2006 when a fourth-year University of Texas graduate student astronomer working for the Palomar Transient Factory’s (PTF) luminous supernova program Robert Quimby discovered the brightest celestial event up to this date. An exploding star over 100 times brighter than a normal supernova and shining brighter than the core of its host galaxy NGC 1260.
“This was a truly monstrous explosion, a hundred times more energetic than a typical supernova,” said Nathan Smith of the University of California at Berkeley, who led a team of astronomers from California and the University of Texas at Austin. “That means the star that exploded might have been as massive as a star can get, about 150 times that of our sun. We’ve never seen that before.”
Teams of astronomers working with the Katzman Automatic Imaging Telescope at the Lick Observatory on Mt. Hamilton in California and M.W. Keck Observatory near the summit of Mauna Kea on the island of Hawaii immediately began observing the event designated supernova SN 2006gy. Analysis of data showed it occurred over 240 million light-years away in galaxy NGC 1260 and took 70 days to reach maximum brightness. Staying brighter than any previously recorded event for over three months, SN 2006gy was still as bright as a normal supernova eight months later.
“Of all exploding stars ever observed, this was the king,” said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, Calif., and the Keck Observatory in Mauna Kea, Hawaii. “We were astonished to see how bright it got, and how long it lasted.”
Astronomers were reasonably sure at this point the progenitor of supernova SN 2006gy was one of the largest, most massive types of stars ever to exist. But they needed to rule out the most likely alternative explanation for the event. The possibility a white dwarf star with a mass slightly higher than Sol went supernova in a dense, hydrogen-rich environment.
Another team of astronomers using the Chandra X-ray Observatory went to work at this point to rule this possibility out of their equations. If this was the case, they knew X-ray emission from the event should be at least 1,000 times more luminous than the readings they were getting.
“This provides strong evidence that SN 2006gy was, in fact, the death of an extremely massive star,” said Dave Pooley of the University of California at Berkeley, who led the Chandra observations.
The progenitor star for SN 2006gy is thought to have ejected a large volume of mass before the hypernova event occurred. This is similar to events observed by astronomers in the case of Eta Carinae, a nearby supermassive star they’re watching closely for signs of an impending supernova. Only 7,500 light-years toward the constellation Carina, compared to 240 million for galaxy NGC 1260, this star going supernova would be the celestial event of the century on Earth. It would be bright enough to see in the daylight sky.
“We don’t know for sure if Eta Carinae will explode soon, but we had better keep a close eye on it just in case,” said Mario Livio of the Space Telescope Science Institute in Baltimore, who was not involved in the research. “Eta Carinae’s explosion could be the best star-show in the history of modern civilization.”
So many questions
Astronomers think in the case of hypernova SN 2006gy things might have taken a slightly different pathway than previously recorded supernovae. Some scientists think the massive star that exploded could be much more like the supermassive stars that existed during the early moments of the cosmos. Supermassive stars that exploded in supernovae and spread the elements of creation across the cosmos, rather than collapsing to a black hole as theorized.
“In terms of the effect on the early universe, there’s a huge difference between these two possibilities,” said Smith. “One [sprinkles] the galaxy with large quantities of newly made elements and the other locks them up forever in a black hole.”
Why would these supermassive stars be different than other huge stars observed in the Milky Way? The human search for answers to these and other mysterious questions before us continues as we journey backward to the beginning of space and time.
We’ll update you with any additional data astronomers come across as the journey continues. Until next time, keep dreaming of the possibilities.
Editor and Chief
The Human Journey to the beginning of space and time.