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The TESS planet hunter successfully launched on a SpaceX Falcon 9 Wednesday evening. TESS will search for new worlds outside our solar system for further study. Image via NASA.

A SpaceX Falcon 9 rocket successfully launched NASA’s TESS mission on Wednesday, April 18, 2018, from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station, Florida. After a delayed launch on Monday, Wednesday’s launch took place at 6:51 p.m. EDT (22:51 UTC; translate UTC to your time). TESS – a first-of-its-kind mission to find worlds beyond our solar system, including some that could support life – was deployed into a highly elliptical orbit approximately 49 minutes after launch. At 7:53 p.m., the twin solar arrays that will power the spacecraft successfully deployed.

Following stage separation, SpaceX successfully landed Falcon 9’s first stage on the droneship Of Course I Still Love You in the Atlantic Ocean.

You can watch a replay of the launch webcast below.

TESS stands for Transiting Exoplanet Survey Satellite. The two-year survey mission is expected to find thousands of new exoplanets – planets orbiting stars other than our sun – orbiting in our neighborhood of the Milky Way galaxy.

How many worlds exist outside our solar system? @NASA_TESS launched from planet Earth today at 6:51pm ET to hunt for planets around some of the closest & brightest stars. TESS will use 4 cameras to search nearly the entire sky for unknown worlds. More: https://t.co/5hUW3XhaTo pic.twitter.com/xuH5q0wqN9

— NASA (@NASA) April 19, 2018

NASA said in a statement:

Over the course of several weeks, TESS will use six thruster burns to travel in a series of progressively elongated orbits to reach the moon, which will provide a gravitational assist so that TESS can transfer into its 13.7-day final science orbit around Earth. After approximately 60 days of check-out and instrument testing, the spacecraft will begin its work …

[For this mission] scientists divided the sky into 26 sectors. TESS will use four unique wide-field cameras to map 13 sectors encompassing the southern sky during its first year of observations and 13 sectors of the northern sky during the second year, altogether covering 85 percent of the sky.

TESS will be watching for phenomena called transits. A transit occurs when a planet passes in front of its star from the observer’s perspective, causing a periodic and regular dip in the star’s brightness. More than 78 percent of the approximately 3,700 confirmed exoplanets have been found using transits.

NASA’s Kepler spacecraft found more than 2,600 exoplanets, most orbiting faint stars between 300 and 3,000 light-years from Earth, using this same method of watching for transits. TESS will focus on stars between 30 and 300 light-years away and 30 to 100 times brighter than Kepler’s targets.

The brightness of these target stars will allow researchers to use spectroscopy, the study of the absorption and emission of light, to determine a planet’s mass, density and atmospheric composition. Water, and other key molecules, in its atmosphere can give us hints about a planet’s capacity to harbor life.

A transit happens when a planet crosses in front of its star as viewed from Earth. Transits by small, rocky planets produce a minute change in a star’s brightness (about 100 parts per million), lasting for 2 to 16 hours. If this tiny change happens again and again, on a regular schedule, it might indicate an orbiting exoplanet. Read more via NASA.

George Ricker is TESS principal investigator at the Massachusetts Institute of Technology’s (MIT) Kavli Institute for Astrophysics and Space Research in Cambridge, Massachusetts. He explained:

One critical piece for the science return of TESS is the high data rate associated with its orbit. Each time the spacecraft passes close to Earth, it will transmit full-frame images taken with the cameras. That’s one of the unique things TESS brings that was not possible before.

Successful deployment of @NASA_TESS to a highly elliptical orbit confirmed. pic.twitter.com/y9CS82cj9N

— SpaceX (@SpaceX) April 18, 2018

Stephen Rinehart is TESS project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. He said:

The targets TESS finds are going to be fantastic subjects for research for decades to come. It’s the beginning of a new era of exoplanet research.

Haven’t got enough yet? SpaceX livestreamed the launch, and you can watch a replay of this launch webcast below …

TESS Mission - YouTube

Bottom line: A SpaceX Falcon 9 rocket successfully launched NASA’s TESS mission on Wednesday, April 18, 2018, from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station, Florida. All systems appear to be go at this time.

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EarthSky | Space by Earthsky Voices - 10h ago

The Milky Way, our own galaxy, stretches across the sky above the La Silla telescope in Chile. Hidden inside our own galaxy are trillions of planets, most waiting to be found. Image via ESO/S. Brunier.

By Pat Brennan, NASA’s Exoplanet Exploration Program

Step outside on a clear night, and you can be sure of something our ancestors could only imagine: Every star you see likely plays host to at least one planet.

The worlds orbiting other stars are called exoplanets, and they come in a wide variety of sizes, from gas giants larger than Jupiter to small, rocky planets about as big around as Earth or Mars. They can be hot enough to boil metal or locked in deep freeze. They can orbit their stars so tightly that a year lasts only a few days; they can orbit two suns at once. Some exoplanets are sunless rogues, wandering through the galaxy in permanent darkness.

That galaxy, the Milky Way, is the thick stream of stars that cuts across the sky on the darkest, clearest nights. Its spiraling expanse probably contains about 400 billion stars, our sun among them. And if each of those stars has not just one planet, but, like ours, a whole system of them, then the number of planets in the galaxy is truly astronomical: We’re already heading into the trillions.

This rocky super-Earth is an illustration of the type of planets future telescopes, like TESS and James Webb, hope to find outside our solar system. Image via ESO/M. Kornmesser

We humans have been speculating about such possibilities for thousands of years, but ours is the first generation to know, with certainty, that exoplanets are really out there. In fact, way out there. Our nearest neighboring star, Proxima Centauri, was recently found to possess at least one planet – probably a rocky one. It’s 4.5 light-years away – more than 25 trillion miles (40 trillion km). The bulk of exoplanets found so far are hundreds or thousands of light-years away.

The bad news: As yet we have no way to reach them, and won’t be leaving footprints on them anytime soon. The good news: We can look in on them, take their temperatures, taste their atmospheres and, perhaps one day soon, detect signs of life that might be hidden in pixels of light captured from these dim, distant worlds.

The first exoplanet to burst upon the world stage was 51 Pegasi b, a hot Jupiter 50 light-years away that is locked in a four-day orbit around its star. The watershed year was 1995. All of a sudden, exoplanets were a thing.

Transit Method Single Planet - YouTube
When a planet passes directly between its star and an observer, it dims the star’s light by a measurable amount. Video via NASA/JPL-Caltech

But a few hints had already emerged. A planet now known as Tadmor was detected in 1988, though the discovery was withdrawn in 1992. Ten years later, more and better data showed definitively that it was really there after all.

And a system of three pulsar planets also had been detected, beginning in 1992. These planets orbit a pulsar some 2,300 light-years away. Pulsars are the high-density, rapidly spinning corpses of dead stars, raking any planets in orbit around them with searing lances of radiation.

Now we live in a universe of exoplanets. The count of confirmed planets is 3,700, and rising. That’s from only a small sampling of the galaxy as a whole. The count could rise to the tens of thousands within a decade, as we increase the number, and observing power, of robotic telescopes lofted into space.

How did we get here?

We’re standing on a precipice of scientific history. The era of early exploration, and the first confirmed exoplanet detections, is giving way to the next phase: sharper and more sophisticated telescopes, in space and on the ground. They will go broad but also drill down. Some will be tasked with taking an ever more precise population census of these far-off worlds, nailing down their many sizes and types. Others will make a closer inspection of individual planets, their atmospheres, and their potential to harbor some form of life.

Direct imaging of exoplanets – that is, actual pictures – will play an increasingly larger role, though we’ve arrived at our present state of knowledge mostly through indirect means. The two main methods rely on wobbles and shadows. The wobble method, called radial velocity, watches for the telltale jitters of stars as they are pulled back and forth by the gravitational tugs of an orbiting planet. The size of the wobble reveals the weight, or mass, of the planet.

This evocative movie of four planets more massive than Jupiter orbiting the young star HR 8799 is a composite of sorts, including images taken over seven years at the W.M. Keck observatory in Hawaii. Image via Jason Wang/Christian Marois.

This method produced the very first confirmed exoplanet detections, including 51 Peg b in 1995, discovered by astronomers Michel Mayor and Didier Queloz. Ground telescopes using the radial velocity method have discovered nearly 700 planets so far.

But the vast majority of exoplanets have been found by searching for shadows: the incredibly tiny dip in the light from a star when a planet crosses its face. Astronomers call this crossing a transit.

The size of the dip in starlight reveals how big around the transiting planet is. Unsurprisingly, this search for planetary shadows is known as the transit method.

NASA’s Kepler space telescope, launched in 2009, has found nearly 2,700 confirmed exoplanets this way. Now in its K2 mission, Kepler is still discovering new planets, though its fuel is expected to run out soon.

Each method has its pluses and minuses. Wobble detections provide the mass of the planet, but give no information about the planet’s girth, or diameter. Transit detections reveal the diameter but not the mass.

But when multiple methods are used together, we can learn the vital statistics of whole planetary systems – without ever directly imaging the planets themselves. The best example so far is the TRAPPIST-1 system about 40 light-years away, where seven roughly Earth-sized planets orbit a small, red star.

The TRAPPIST-1 planets have been examined with ground and space telescopes. The space-based studies revealed not only their diameters, but the subtle gravitational influence these seven closely packed planets have upon each other; from this, scientists determined each planet’s mass.

So now we know their masses and their diameters. We also know how much of the energy radiated by their star strikes these planets’ surfaces, allowing scientists to estimate their temperatures. We can even make reasonable estimates of the light level, and guess at the color of the sky, if you were standing on one of them. And while much remains unknown about these seven worlds, including whether they possess atmospheres or oceans, ice sheets or glaciers, it’s become the best-known solar system apart from our own.

Where are we going?

The next generation of space telescopes is upon us. First up was Wednesday’s launch of TESS, the Transiting Exoplanet Survey Satellite. This extraordinary instrument will take a nearly full-sky survey of the closer, brighter stars to look for transiting planets. Kepler, the past master of transits, will be passing the torch of discovery to TESS.

TESS, in turn, will reveal the best candidates for a closer look with the James Webb Space Telescope, currently scheduled to launch in 2020. The Webb telescope, deploying a giant, segmented, light-collecting mirror that will ride on a shingle-like platform, is designed to capture light directly from the planets themselves. The light then can be split into a multi-colored spectrum, a kind of bar code showing which gases are present in the planet’s atmosphere. Webb’s targets might include super Earths, or planets larger than Earth but smaller than Neptune – some that could be rocky planets like super-sized versions of our own.

An illustration of the different missions and observatories in NASA’s exoplanet program, both present and future. Image via NASA.

Little is known about these big planets, including whether some might be suitable for life. If we’re very lucky, perhaps one of them will show signs of oxygen, carbon dioxide and methane in its atmosphere. Such a mix of gases would remind us strongly of our own atmosphere, possibly indicating the presence of life.

But hunting for Earth-like atmospheres on Earth-sized exoplanets will probably have to wait for a future generation of even more powerful space probes in the 2020s or 2030s.

Thanks to the Kepler telescope’s statistical survey, we know the stars above are rich with planetary companions. And as we stare up at the night sky, we can be sure not only of a vast multitude of exoplanet neighbors, but of something else: The adventure is just beginning.

Bottom line: Worlds orbiting other stars are called exoplanets. How we know they’re out there, plus the potential for finding more via the newly launched TESS mission.

Read more: TESS planet hunter on its way

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Moon and Venus on April 17 to 19

CJ Meyer wrote, “Clear skies tonight looking west just after sunset with the crescent moon, Venus, Aldebaran (Taurus) and the Pleiades all visible. Ndola, Zambia.”

Rod Cerkoney captured this image over Fort Collins, Colorado, on April 17, 2018. He said, “High winds and clouds most of the day. But the clouds dissipated in the early evening (not the winds) long enough to enjoy the moon and Venus hovering above a local landmark – Horsetooth Rock.”

A drone captured this image in Orange, California, April 17, 2018. Image via Michael Daugherty.

Steve Browne wrote, “Peek-a-boo, I see you. The moon and Venus hiding in the trees.” Morehead City, North Carolina, April 17, 2018.

View larger | You have to look closely to spy Venus in the upper right in this image. Dave Chapman took this photo at the Atacama Space Lodge in San Pedro de Atacama, Chile on April 16, 2018.

Crescent moon and Venus over southern Wisconsin April 17, 2018. Photo via Suzanne Murphy.

Véronique Lannerée? wrote, “Beautiful rendezvous this night with Venus and a thin crescent moon, from France.”

Bottom line: Photos of the moon and Venus in April 2018.

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Simulated view of a small body ramming into Mars, kicking up debris that eventually formed its 2 small moons. Image via Robin Canup/SWRI.

It’s long been suggested that Mars’ two moons – called Phobos and Deimos (Panic and Terror) for the two horses of the mythological war god Mars – are captured asteroids. After all, Mars orbits just one step inward from the asteroid belt. And the two moons resemble rocky C-type asteroids, the most common kind of asteroids, in terms of their estimated densities and reflected light. Questions have remained, however, particularly regarding the nearly circular orbits of the moons. On April 18, 2018, scientists at the Southwest Research Institute (SwRI) in Boulder, Colorado announced new work based on state-of-the-art computer modeling, suggesting an alternate origin for Mars’ moons. The work suggests a violent birth for the moons – much like mighty impact that might have formed Earth’s own moon – but on a much smaller scale.

The new work is published in the peer-reviewed journal Science Advances. Its lead author, Robin Canup, is an expert in using large-scale hydrodynamical simulations to model planet-scale collisions. She said:

Ours is the first self-consistent model to identify the type of impact needed to lead to the formation of Mars’ two small moons.

A key result of the new work is the size of the impactor; we find that a large impactor – similar in size to the largest asteroids Vesta and Ceres – is needed, rather than a giant impactor.

The model also predicts that the two moons are derived primarily from material originating in Mars, so their bulk compositions should be similar to that of Mars for most elements. However, heating of the ejecta and the low escape velocity from Mars suggests that water vapor would have been lost, implying that the moons will be dry if they formed by impact.

This composite image compares how big the moons of Mars appear, as seen from the surface of the Red Planet, in relation to the size that our moon appears from Earth’s surface. While Earth’s moon is 100 times bigger than the larger Martian moon Phobos, the Martian moons orbit much closer to their planet, making them appear relatively larger in the sky. Deimos, at far left, and Phobos, beside it, are shown together as photographed by NASA’s Mars rover Curiosity on August 1, 2013. Image via NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M University/SWRI.

A statement from these scientists explained more:

The new Mars model invokes a much smaller impactor than considered previously. Our moon may have formed when a Mars-sized object crashed into the nascent Earth 4.5 billion years ago, and the resulting debris coalesced into the Earth-moon system. The Earth’s diameter is about 8,000 miles, while Mars’ diameter is just over 4,200 miles. The moon is just over 2,100 miles in diameter, about one-fourth the size of Earth.

While they formed in the same timeframe, Deimos and Phobos are very small, with diameters of only 7.5 miles and 14 miles respectively, and orbit very close to Mars. The proposed Phobos-Deimos forming impactor would be between the size of the asteroid Vesta, which has a diameter of 326 miles, and the dwarf planet Ceres, which is 587 miles wide.

These scientists say their work is particularly significant for the Japan Aerospace Exploration Agency (JAXA) Mars Moons eXploration (MMX) mission, which is planned to launch in 2024. The MMX spacecraft will visit the two Martian moons, land on the surface of Phobos and collect a surface sample to be returned to Earth in 2029. Canup said:

A primary objective of the MMX mission is to determine the origin of Mars’ moons, and having a model that predicts what the moons compositions would be if they formed by impact provides a key constraint for achieving that goal.

Discovered in 1877, the larger of the 2 Mars moons – potato-shaped Phobos – is so small that it appears starlike in Hubble Space Telescopes pictures. The other moon, Deimos, is even smaller. Image via HubbleSite.

Bottom line: State-of-the-art computer modeling suggests Mars’ moons formed in a collision between primitive Mars and a dwarf-planet-sized body, early in the solar system’s history.

Source: Origin of Phobos and Deimos by the Impact of a Vesta-to-Ceres-sized Body with Mars

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The sun today, April 17, 2018, via NASA Solar Dynamics Observatory.

Stars are typically born in star clusters, and our sun likely was, too. The sun’s home cluster would have been pulled apart relatively quickly, as the cluster moved through the space of our Milky Way galaxy. Today, the sun’s sibling stars would be scattered across our sky. But clues to the sun’s siblings remain. For example, astronomers would expect each star in the sun’s birth cluster to have the same chemical composition. On April 17, 2018 – in the 1st major public data release from a galactic archaeology survey, called the GALAH Survey – astronomers in Australia and Europe announced they’ve mapped the chemical profiles of 350,000 stars in our Milky Way. They’re referring to this information, somewhat fancifully, as the stars’ DNA. Among other information culled from the GALAH data, they say, we may discover the lost siblings of our sun.

The GALAH Survey was launched in late 2013. It uses a sophisticated computer code to analyze spectroscopic data on the stars, obtained from the HERMES spectrograph at the 3.9-meter Anglo-Australian Telescope at the Australian National University’s Siding Spring Observatory. Martin Asplund of Australian National University led the recent analysis. He said that – when it’s finished – GALAH will help reveal original star clusters for our sun and more than one million other stars. He said:

This survey allows us to trace the ancestry of stars, showing astronomers how the universe went from having only hydrogen and helium — just after the Big Bang — to being filled with all the elements we have here on Earth that are necessary for life.

Gayandhi De Silva of the University of Sydney is the HERMES instrument scientist who oversaw the groups working on the April 17 data release. He commented:

No other survey has been able to measure as many elements for as many stars as GALAH.

The GALAH team has spent more than 280 nights at the telescope since 2014 to gather all the data collected so far. These astronomers say their survey will, for the first time, provide:

… a detailed understanding of the history of the galaxy.

Rainbow Fingerprints - YouTube

Bottom line: On April 17, 2018, in the 1st major public data release from the GALAH Survey, astronomers in Australia and Europe announced they’ve mapped the chemical profiles of 350,000 stars in our Milky Way. The goal is to understand our galaxy’s history. Along the way, they may find the lost siblings of our sun.

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Artist’s concept of gravitational waves via ScienceBlog.

In 2016, the LIGO Scientific Collaboration announced the first direct observations of short bursts of gravitational waves – ripples in the fabric of space-time – in this case, created during the merger of black holes. Late last year, LIGO said it had detected the first gravitational waves from colliding neutron stars. On April 10, 2018, scientists in Europe announced a search for a different type of gravitational wave signal, the long continuous waveform expected from a single rapidly spinning neutron star. The scientists said they’d established a new permanent independent research group to search for such objects.

Maria Alessandra Papa is leading the group at the Max Planck Institute for Gravitational Physics in Hannover, Germany. The announcement said:

It is the largest group worldwide dedicated to this topic and conducts the most sensitive searches for this kind of gravitational wave with the globally distributed volunteer computing project Einstein@Home. In addition to its permanent funding, the group will receive additional funds from the Max Planck Society for the first five years.

Papa explained:

With the first direct detections of gravitational waves from merging black hole and neutron star pairs, we have done the first steps into new astrophysical territory.

But much of this new continent is still uncharted. While we do know that there are about 100 million single neutron stars in our galaxy, we have only identified about 3,000 of them. We want to unveil this mostly invisible population by detecting their continuous gravitational-wave emission.

A neutron single star swiftly rotating on its axis – with a large mountain or other irregularity on it – might produce continuous gravitational waves. The gravitational waves would be weak compared to the short bursts produced by, for example, black hole mergers. Image via LIGO.

The statement from Max Planck Institute further explained:

The type of gravitational wave emitted by single neutron stars is very different from the signals already detected. Rapidly rotating neutron stars can emit much fainter but much longer duration (continuous) gravitational waves. Finding these waves is very difficult and limited by the amount of computing power available for the searches. This is because there are many unknowns to search over wide ranges: the star’s sky position, its spin rate, and its deformation responsible for the gravitational-wave emission.

The Einstein@Home volunteer computing project provides the lion’s share of the required compute cycles for the state-of-the-art search techniques.

Read more about how Einstein@Home works

Einstein@Home applications

Maria Alessandra Papa. Image via T. Damm/Max Planck Institute.

Bottom line: Scientists first observed gravitational waves from merging black holes. Now they’re seeking a different gravitational wave signal – a long continuous waveform from a rapidly spinning neutron star.

Via Max Planck Institute

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Illustration of the orbit of asteroid 2018 GE3. The orbit appears to extend to the inner part of the asteroid belt between Mars and Jupiter. Image via Tomruen/Wikimedia Commons.

A medium-sized asteroid buzzed by Earth just hours after being detected this weekend. First observed at Catalina Sky Survey in Arizona on Saturday, April 14, 2018, the asteroid – which has been labeled 2018 GE3 – swept past us at about half the Earth-moon distance early Sunday morning according to clocks in North America. Closest approach to Earth occurred at around 2:41 a.m. EDT (6:41 UTC; translate UTC to your time) on April 15.

Its closest point to Earth was just 119,500 miles (192,317 km) away. That’s in contrast to the moon’s quarter-million-mile (400,000 km) distance. According to NASA, hours later, at about 5:59 a.m. EDT on April 15, the space rock passed even closer to the moon than it had to Earth.

With an estimated diameter of 157 to 361 feet (48 to 110 meters), asteroid 2018 GE3 has about three to six times the diameter of the space rock that penetrated the skies over Chelyabinsk, Russia in February 2013, causing some 1,500 people to seek treatment for injuries, mostly from flying glass.

Asteroid 2018 GE3, an Apollo type earth-crossing asteroid, was flying through space at 66,174 miles per hour (106,497 km/h).

If the asteroid had entered our atmosphere, a great portion of the space rock would have disintegrated due to friction with the air. However, some of an asteroid this size might have gotten through to Earth’s surface, and an asteroid this big is capable of causing some regional damage, depending on various factors such as composition, speed, entry angle, and location of impact. It might make you feel better (or worse) to know that asteroids enter Earth’s atmosphere unnoticed on a fairly regular basis.

For example, in 2014, scientists announced 26 atom-bomb-scale asteroid impacts since 2000 that were discovered in data from the Nuclear Test Ban Treaty Organization, which operates a network of sensors that monitors Earth around the clock listening for the infrasound signature of nuclear detonations. Earth’s atmosphere does a good job of protecting us from incoming asteroids. Most explode high in the atmosphere, or over an ocean, and therefore do no harm.

Was Earth in danger from 2018 GE3? Not this time, but a Chelyabinsk-type event can clearly repeat. Astronomers have increased their programs to seek near-Earth asteroids like 2018 GE3, but sometimes – like this time and as in 2013 with the Chelyabinsk event – asteroids do still surprise us.

A preliminary analysis of the orbit of 2018 GE shows this is the closest this particular space rock has come to Earth at least since 1930.

Asteroid 2013 GE3 at NASA’s Small Body Database

Asteroid 2018 GE3 by Michael Jaeger. Used with permission.

Bottom line: Asteroid 2018 GE3 swept by at half the moon’s distance Sunday, just hours after being detected.

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The video above – via MIT astrophysicist Carl Rodriguez – shows a simulation of the dynamics of 50 black holes in the center of a globular star cluster. It shows how single black holes may eventually form a binary black hole, where two black holes orbit each other. For the past few years, Rodriguez has been investigating the behavior of black holes within globular clusters. He’s wondered whether their interactions are different from black holes occupying less populated regions in space. He recently led an international team of astrophysicists, whose work suggests that black holes in globular star clusters might partner up and merge multiple times. The mergers would produce black holes more massive than those that form from single stars.

The study was published on April 10, 2018, in the peer-reviewed journal Physical Review Letters (view online). A statement from MIT explained:

In their new paper, Rodriguez and his colleagues report using a supercomputer called Quest, located at Northwestern University, to simulate the complex, dynamical interactions within 24 stellar clusters, ranging in size from 200,000 to 2 million stars, and covering a range of different densities and metallic compositions. The simulations model the evolution of individual stars within these clusters over 12 billion years, following their interactions with other stars and, ultimately, the formation and evolution of the black holes. The simulations also model the trajectories of black holes once they form.

Rodriguez said:

The neat thing is, because black holes are the most massive objects in these clusters, they sink to the center, where you get a high enough density of black holes to form binaries. Binary black holes are basically like giant targets hanging out in the cluster, and as you throw other black holes or stars at them, they undergo these crazy chaotic encounters.

A simulation showing an encounter between a binary black hole (in orange) and a single black hole (in blue) with relativistic effects. Eventually two black holes emit a burst of gravitational waves and merge, creating a new black hole (in red). Image via Northwestern Visualization/Carl Rodriguez/MITNews.

A snapshot of a simulation showing a binary black hole formed in the center of a dense star cluster. Image via Northwestern Visualization/Carl Rodriguez/MITNews.

Globular clusters are symmetrical star clusters – hundreds of thousands to millions of stars – orbiting in the halos of galaxies including our Milky Way. These clusters are thought to contain a galaxy’s oldest stars. Rodriguez said:

We think these clusters formed with hundreds to thousands of black holes that rapidly sank down in the center. These kinds of clusters are essentially factories for black hole binaries, where you’ve got so many black holes hanging out in a small region of space that two black holes could merge and produce a more massive black hole. Then that new black hole can find another companion and merge again.

These scientists referred to the process of black holes merging within globular star clusters as second-generation mergers.

M13, the largest and brightest globular star cluster visible in Northern Hemisphere skies, seen through an 8-inch telescope. Image via KuriousGeorge/Wikimedia Commons.

The subject of binary black holes has been of interest to astronomers since scientists with the LIGO twin detectors announced the first direct detection of gravitational waves in early 2016. The waves are thought to come from binary black holes. A statement from MIT said:

If LIGO detects a binary with a black hole component whose mass is greater than around 50 solar masses, then according to the group’s results, there’s a good chance that object arose not from individual stars, but from a dense stellar cluster.

Rodriguez added:

If we wait long enough, then eventually LIGO will see something that could only have come from these star clusters, because it would be bigger than anything you could get from a single star.

Read more via MITNews

Here are 119 of the approximately 200 known globular clusters orbiting the center of our Milky Way galaxy. The closest globular cluster to us lies about 7,000 light-years from Earth. Image via RASC.

Bottom line: An international team of astrophysicists used a supercomputer to model the behavior of black holes in globular star clusters. They found that the black holes could be expected to partner up and merge multiple times and to produce black holes more massive than those that form from single stars.

Source: Post-Newtonian Dynamics in Dense Star Clusters: Highly-Eccentric, Highly-Spinning, and Repeated Binary Black Hole Mergers

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Image via NASA.

NASA’s Transiting Exoplanet Survey Satellite (TESS) is set to launch on a SpaceX Falcon 9 rocket from Cape Canaveral Air Force Station in Florida on Monday evening (April 16, 2018.) Once in orbit, TESS will spend about two years surveying 200,000 of the brightest stars near the sun to search for planets outside our solar system.

To watch the launch, tune in to NASA TV. Lift-off is planned for no earlier than 6:32 p.m. EDT (10:32 UTC; translate to your time). Prelaunch mission coverage will begin on Sunday, April 15, with three live briefings. Watch here.

According to a NASA statement:

TESS is NASA’s next step in the search for planets outside of our solar system, known as exoplanets, including those that could support life. The mission is expected to catalog thousands of planet candidates and vastly increase the current number of known exoplanets. TESS will find the most promising exoplanets orbiting relatively nearby stars, giving future researchers a rich set of new targets for more comprehensive follow-up studies, including the potential to assess their capacity to harbor life.

Read more: Goodbye Kepler, hello TESS: Passing the baton in exoplanet search

Bottom line: The TESS planet-hunting mission will launch on April 16, 2018.

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Low 3-D Flyover of Jupiter’s North Pole in Infrared - YouTube

Data for the dramatic imagery used in the animated 3-D fly-around of Jupiter’s north pole, above, was collected by the Juno spacecraft a year ago, in its fourth sweep past the planet. Juno mission scientists shared this movie this week (April 11, 2018) during the European Geosciences Union General Assembly (EGU2018) in Vienna, Austria. Among other things, the movie shows the densely packed cyclones and anticyclones at Jupiter’s poles. NASA said:

Infrared cameras are used to sense the temperature of Jupiter’s atmosphere and provide insight into how the powerful cyclones at Jupiter’s poles work. In the animation, the yellow areas are warmer (or deeper into Jupiter’s atmosphere) and the dark areas are colder (or higher up in Jupiter’s atmosphere) …

Juno mission scientists have taken data collected by the spacecraft’s Jovian InfraRed Auroral Mapper (JIRAM) instrument. Imaging in the infrared part of the spectrum, JIRAM captures light emerging from deep inside Jupiter equally well, night or day. The instrument probes the weather layer down to 30 to 45 miles (50 to 70 km) below Jupiter’s cloud tops. The imagery will help the team understand the forces at work in the animation – a north pole dominated by a central cyclone surrounded by eight circumpolar cyclones with diameters ranging from 2,500 to 2,900 miles (4,000 to 4,600 km).

Wow, yes?

Alberto Adriani, Juno co-investigator from the Institute for Space Astrophysics and Planetology in Rome, Italy said:

Before Juno, we could only guess what Jupiter’s poles would look like.

The Juno spacecraft has been in orbit around Jupiter since 2016. It’s in a highly elliptical polar orbit, taking it to within 2,600 miles (4,200 km) of the planet and then out to 5 million miles (8.1 million km), far beyond the orbit of Callisto, the most distant of Jupiter’s four large Galilean moons. Thus Juno sweeps closest to Jupiter only every 53 days. The spacecraft is expected to complete 12 science orbits of the giant planet before the end of its budgeted mission plan in July 2018.

Infrared 3-D image of Jupiter’s north pole, derived from data collected by the Jovian Infrared Auroral Mapper (JIRAM) instrument aboard the Juno spacecraft. Image via NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM.

Bottom line: This week, scientists meeting at EGU2018 in Vienna, Austria, presented this animated 3-D fly-around of Jupiter’s north pole, made possible by data collected via the Juno spacecraft.

Via NASA Juno

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