Astronomy News – Black holes are stellar objects of the most unusual nature and temperament. They’re also something we haven’t witnessed being born during the human journey to the beginning of space and time, until now. NASA astronomers using the Chandra X-ray Observatory to take a look at W49B, a 1,000-year-old supernova remnant, found it to be unlike any they have observed before. In fact, this supernova remnant could have left behind a black hole.
There should be some mass left over in the form of a neutron star
When the most massive suns reach the end of their lives, their central regions collapse and trigger a chain of events that ends in a supernova explosion. Astronomers studying W49B found this supernova remnant was formed when mass from the poles of a 25-solar mass star shot out at a much higher speed than mass shooting from the equator. This is the first supernova remnant with this characteristic they have found in the Milky Way.
Looking for the rabbit hole
Astronomers also couldn’t find the characteristic neutron star they expected to detect within the remnant, which leaves scientists wondering if there’s a black hole lurking somewhere within the cloud. Star scientists are currently studying data concerning W49B, trying to find the telltale evidence they need to indicate the presence of a black hole. Should they find the evidence they’re looking for this will be the first opportunity to study a supernova responsible for creating a young black hole.
Anasazi Indians astronomy knowledge written in desert rocks
Ancient Astronomy – The Anasazi civilization flourished throughout the American southwest over 1,000 years ago, before vanishing into the annals of history. Forgotten on the hot mesas of the southwestern desert, remains of their stone cities and enigmatic causeways offer quiet testament to their innovation and determination. Carved in the desert rocks of New Mexico archaeologists also found symbols that indicate astronomy was an integral part of Anasazi society and that they spent hundreds of years watching and studying the sky.
Skywatchers of the American Southwest
Modern archaeoastronomers believe the Anasazi were ancient sky watchers who interpreted signs in the sky in order to construct a calendar they could use to aid farming. High on a ledge near the top of a soaring butte in New Mexico’s Chaco Canyon, they found three large stone slabs forming an opening, through which sunlight shined onto two spirals carved in the stone behind the slabs. For possibly longer than 1,000 years, until the slabs shifted due to erosion, beams of sunlight correctly predicted the summer and winter solstices, as well as the March and September equinoxes. Archaeologists believe the Sun Dagger, as the spectacle is called, was a calendar devised by Anasazi astronomers.
Anasazi astronomer recorded death of star
Archaeoastronomers also found marks on an overhanging rock on a cliff beneath the remains of the Anasazi town called Penasco Blanco suggesting Anasazi astronomers witnessed the death of a star almost a thousand years ago. Displayed on a rock face, they found three colored figures, a hand, a crescent, and a rayed disk. Painted on the sandstone wall beneath the figures is a dot, with two rings around it. Archaeoastronomers believe the cliff was possibly a post used by Anasazi astronomers and sun watchers, much like other similar posts archaeologists have found in the southwestern territories.
The crescent isn’t a figure archaeologists have seen carved in rock faces around the southwest very often, so they believe this could represent a spectacular event in the history of the Anasazi. The rayed disk some archaeoastronomers believe might represent an exploding star, which would have appeared in the sky around 1,000 years ago. At that time, over in China, astronomers recorded the appearance of a “guest star” in the sky on July 5, 1054. This guest star some archaeoastronomers believe was a supernova marking the death of a massive star in the constellation Taurus, the remains of which are the Crab Nebula.
Did Anasazi astronomers record the death of a star 1,000 years ago in paintings they carved in an overhanging rock below the town of Penasco Blanco? Some archaeoastronomers believe this might be the case. NASA astronomer John Brandt tried to verify this in 1979, by having a friend reproduce the night sky above the town in July 1054. They discovered the night sky above the town was almost exactly as depicted in the rock face in Chaco Canyon.
If the evidence is assembled and to be believed, around 1,000 years ago an Anasazi astronomer took up his post below the town of Penasco Blanco as the sun was about to rise above the horizon. Keeping his eyes toward the eastern horizon, he observed as the moon rose with a star of amazing brilliance suspended almost in the curve of its upside-down crescent. Captivated by the appearance of this guest star in the sky, the astronomer marked the moment in time by carving its image into the rock.
Astronomy questions and answers – You have probably heard the expression, “We’re all just star dust” The truth is, depending on the age of the atoms in your body, you could have been stardust several times, by now. The average length of time astronomers estimate it takes atoms discharged during a supernova in the Milky Way to be recycled into a new star or solar system is several billion years.
How old is the stardust in you?
Figuring out the true age of the atoms in your body is going to be the hard part. Astronomers can give you an estimate for the age of the solar system, the Milky Way, and the universe. The numbers are insignificant to the question since we have no way of knowing where your atoms have been during the estimated 13.798 + or – 0.037 billion years the universe has been in existence. Your atoms could have been part of any number of solar systems and stars, by now.
We could narrow the estimate a bit, for you, but we would need to make two assumptions. Firstly, that the Milky Way is the only galaxy your atoms have been a part of during the past. This is most likely the case since astronomers believe galaxies formed relatively soon after the Big Bang. Secondly, that the heavy atoms in your body have only been part of one supernova during their existence. This assumption could possibly be a bit of a stretch, but even being part of one supernova, and returning to be reconsolidated would take several billion years. Once we do this, it becomes easier to narrow the estimate a bit.
A grain of stardust ejected during a supernova can follow a few different roads. It could be flung right out of its host galaxy as part of the galactic wind. Astronomers estimate maybe half of the star dust in the Milky Way presently will eventually follow this road. A percentage of this star dust will certainly be destroyed by the Milky Way’s hot halo, while the remainder will fall back into the galaxy. All most all of the stardust ejected from the galaxy in this way will never become part of a new star or solar system. The whole process is estimated by astronomers to take at least 10 billion years. Since we assume the heavy atoms of your body have only been part of the Milky Way and a single supernova, 10 billion years is an upper limit of the age of the atoms in your body.
Dust grains that aren’t ejected from the galaxy during a supernova event will become part of the interstellar medium (ISM). This is the low-density stardust that makes up the space between the stars. The majority of this stardust will also never make it into a new star or solar system. The star dust that does make it back into a new star or solar system will take several billion years to complete the process, as we mentioned above. Several means more than one or two, but not much more, so we’ll say around five billion years it has taken the atoms in your body to become part of the solar system. Astronomers studying the solar system also believe the solar system is around 4.6 billion years old, give or take a few million, and this is close to our estimate of 5 billion years old.
A rough estimate of the age of the stardust in you
There you have a rough estimate of the age of the atoms in your body. From 5 to 10 billion years, given the two assumptions we made. The real point is we are all made of stardust, no matter the age of the atoms in our body.
Click this link to watch a documentary with Neal DeGrasse Tyson on whether we are made of stardust.
Stars begin life as clouds of cold gas and dust that transform into blazing hot fireballs
Star dust, star dust, burning bright
Amid the glare of ancient light
Eternity stares back from the past
Reborn we’ll be one day at last
NASA astronomy: stellar astrophysics
Astronomy questions and answers – September 19, 2013 – Walk out to a dark viewing spot anywhere on the Earth on a clear night and look up at the night sky. Your eyes will take in ancient light from stars in the Milky Way that covers the whole sky above you. Deep within the stellar nurseries of the Milky Way new stars are being formed using processes NASA astronomers are currently studying in an attempt to understand how stars are born. Star forming processes responsible for the formation of the stars you see in the night sky. Processes they can see at work in the stellar nurseries of the Milky Way, like the Orion Nebula (M42) and Cygnus X.
Journey with me to stellar nurseries deep within the dark regions of the Milky Way, the dark patches you can see in the night sky above. The birthing grounds of young stars in the Milky Way, these dark patches in the night sky are in fact clouds of interstellar gas that appear dark because they block the starlight from distant stars. Astronomers believe deep within the birthing grounds of the Milky Way, new stars are being formed at the rate of about 2 or 3 new stars each year.
Star formation theories
Present theories on star formation put forth by NASA astronomers show star formation is a complicated process affected by nearby massive stars, other star forming regions, and even the spiral structure of the Milky Way. These theories only become more complicated when astronomers look at the formation of groups of stars.
In order to try to simulate star formation, some astronomers use sophisticated computer models, while others incorporate observations in different wavelengths and use them to create three-dimensional images of the sky. Working together these two different groups of astronomers are trying to determine exactly how stars are born.
NASA astronomers working on present theories of star formation think the Milky Way is filled with clouds of gas and dust they call the interstellar medium. They also think slight over densities within these clouds of gas and dust could trigger star formation, over densities that could be produced by the turbulent forces present in these clouds of gas and dust. Astronomers studying slight over densities within star forming clouds of gas and dust believe these slightly denser regions could eventually become main sequence stars within a few million years.
Some NASA astronomers believe the intense radiation from groups of hot, bright stars located close to one another could create the necessary turbulence in the interstellar medium to trigger star formation. Other astronomers believe nearby galaxies and even large clouds of gas and dust could cause turbulence in the interstellar medium which could also be part of the star forming process. Many astronomers also believe the resulting shock wave after a supernova could create spiral density waves capable of compressing material and initiating star formation.
Gravity at Work
Present theories on the formation of main sequence stars being proposed by NASA astronomers involves the force of gravity. Gravity pulls the gas and dust within the interstellar medium into denser regions, which results in a cloud increasing in size and contracting. The rotation velocity of the cloud increases as it contracts due to conservation of angular momentum, in the same way a figure skater’s spin speed increases as they bring their arms closer to their body.
At the same time the temperature in the core of the cloud increases as it shrinks due to the force of gravity. The charged particles within the cloud at this time can only move in specific directions in the magnetic field in the region. This results in the rotational velocity of the cloud slowing, but not stopping, otherwise astronomers think stars would never form in these dense clouds of gas and dust.
In the case of main sequence stars astronomers think regions of dense clouds of gas and dust would begin to contract to an area the size of our solar system tens of thousands of years after beginning to slow. At this time astronomers think the temperature at the centre of dense clouds of dust and gas would be in the region of 10,000 kelvins. They call the central region of such a cloud at this time a protostar.
Protostars at this time in their life cycle are often more luminous than the main sequence star they eventually become, because they have a greater surface from which to radiate energy. This brightness allows NASA astronomers to view protostars as they continue to gravitationally attract more gas and dust, shrink and heat up internally. The luminosity of a protostar begins to decrease as it’s outer surface shrinks under the force of gravity. Astronomers believe the cloud and protostar eventually spin faster and flatten out into a disk.
Astronomers using data collected by several different astronomical instruments recently presented far-infrared images of three Class 0 protostar systems in Perseus: L1448C, the triple system L1448N, and IRAS 03282+3035. Seven hundred and fifty light-years from Earth, all three of these protostars were seen powering bipolar molecular outflows, which astronomers think are in fact epic jets of water being thrust into interstellar space. Calculations by NASA astronomers indicates these jets of water are shooting out into interstellar space at speeds of around 120,000 miles per hour and at a rate equal to about 100 million times the volume of water flowing in the Amazon every second of the day.
Astronomers think these jets of water and material help to channel radiation and mass away from the protostar, which helps to clear the central region of debris and reveal the protostar. They also think it could be possible the galaxy was seeded with water through this process, which might change thoughts on the possibility of life in the galaxy. The remaining material is then accreted by the protostar, or forms part of a residual disk, which NASA astronomers think could form planets.
The core of a protostar will reach 1 million kelvin at sometime during the contraction and heating up of the cloud, at which time it will begin fusing deuterium to helium. Deuterium is the easiest nucleus to fuse, so it makes sense this would be the starting point. Once the core has contracted enough to reach a density where the core reaches 10 million degrees kelvins, hydrogen nuclei will begin fusing into helium. At this point star astronomers also think a protostar will reach an equilibrium point where the radiative energy from fusion balances gravitational pull of its mass. This new star is now a main sequence star, which has formed over millions of years.
Simulating the Birth of a Star
The process of star birth takes millions of years to complete, so how do astronomers determine the way outside factors affect the process by which new stars are born? Modern astronomers are presently using supercomputers to help simulate star formation models in the hope they can determine why the mass distribution of newly formed stars appears to be universal. They want to understand why this average mass of newly formed stars exists. They also want to know the process by which it occurs.
Present star formation models take into account the effects of thermodynamics, magnetic fields, radiative processes, and of course gravity. Star astronomers are also trying to determine other factors they need to include in models, like the way new stars affect their own star forming environments. This includes factors like young stars heating up the gas and dust surrounding them and moving gas and dust around through bipolar molecular flows.
The key question NASA astronomers want to answer at this point is whether or not present star formation models can reproduce the properties of exact parts of the star forming process. Astronomers will also want to determine the most massive star that can be formed depending on the size of a cloud of dust and gas. They’ll try to find answers by looking at the chemical composition, magnetic fields, ionization, age and other factors of large clouds of star forming dust and gas in the night sky.
Peering into Stellar Nurseries
How do NASA astronomers look into the heart of stellar nurseries in the Milky Way? Astronomers use instruments designed to detect specific wavelengths of light radiation emitted during the formation of new stars. During the beginning stages of star birth a new star emits radio waves as it contracts astronomers look for as an indicator of new star formation. At this time the core of a contracting cloud of gas and dust is too cold to emit visible and infrared radiation.
Once the cloud forms a protostar it will begin to emit light radiation, which will be blocked by the material surrounding the new star. The light radiation emitted by a protostar is absorbed by the surrounding material, which radiates infrared radiation toward Earth NASA astronomers detect using space and ground-based telescopes specifically designed for the job.
Astronomers have used the Spitzer Space Telescope to view hundreds of protostars forming in large clouds of gas and dust in the stellar nurseries of the Milky Way. In the future they’ll use instruments and telescopes designed to detect millimetre waves in the microwave range in order to get a better view of the beginning stages of star birth. To date astronomers report detecting a compact source embedded in cold gas within stellar nurseries only detectable at these wavelengths.
NASA astronomers trying to piece together the puzzle of star formation in the Milky Way are also using reconstructed images of star-forming regions from past observations. Using 2-D images, positional data, and velocities for an entire cloud, they have been able to create 3-D models researchers can then analyze. 3-D models that show unforeseen structures hidden within stellar nurseries and even regions of star formation they weren’t expecting to see.
Click this link to watch a You Tube videos on how a star is born
Astronomy News – A supernova is one of the most spectacular and massive events astronomers journeying backward to the beginning of space and time view, and can often be billions of times as bright as Sol, or shine brighter than an entire galaxy. Take a journey to a supernova, like SN 2005E, which astronomers became aware of when it lite up the spiral galaxy NGC 1032 in 2005, and your view of life and the universe would change forever.
Astronomers spend countless hours looking for new supernovae to study
Astronomers had previously only viewed supernovae occurring in two ways during their Journey to the Beginning of Space and Time. In the first example, the massive core of a star collapses inward near the end of its life cycle, creating a shock wave that expels the star’s outer layers into the cold darkness of space and time. In the second, a white dwarf star steals matter from a companion star, until it reaches 1.4 solar masses. At this point, the white dwarf star is unable to support more mass, according to natural law, and detonates in a titanic stellar explosion brighter than a galaxy.
A team of astronomers looking at the data obtained by space scientists studying supernova SN 2005E believe this supernova could represent a third as yet unseen, path nature uses to create a supernova. This analysis of this team of scientists has determined that this supernova occurred in a region of space and time devoid of massive stars. They also determined that this supernova only ejected a small volume of stellar material (0.3 solar masses) and abnormally high levels of calcium and radioactive titanium into the universe.
Team member Alex Filipenko of the University of California, Berkeley, and team leaders Hagai Perets of the Harvard-Smithsonian Center for Astrophysics in Cambridge and Avishay Gal-Yam of the Weizmann Institute of Science in Rehovot, Israel, conclude supernova SN 2005E took place between a low-mass white dwarf star that was stealing helium from a companion star. They also believe the volume of calcium released during supernova SN 2005E was large enough that only a few similar supernovae would be sufficient per century to provide all of the calcium presently viewed in the Milky Way Galaxy.