Space and astronomy news
There are regular volcanoes, and then there are the supervolcanoes. Massive calderas of hot magma of incomprehensible size. Bad news, these things explode randomly and catastrophically. Worse news, there are a bunch around the Earth.
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For centuries, scientists have been attempting to explain how the Moon formed. Whereas some have argued that it formed from material lost by Earth due to centrifugal force, others asserted that a preformed Moon was captured by Earth’s gravity. In recent decades, the most widely-accepted theory has been the Giant-impact hypothesis, which states that the Moon formed after the Earth was struck by a Mars-sized object (named Theia) 4.5 billion years ago.
According to a new study by an international team of researchers, the key to proving which theory is correct may come from the first nuclear tests conducted here on Earth, some 70 years ago. After examining samples of radioactive glass obtained from the Trinity test site in New Mexico (where the first atomic bomb was detonated), they determined that samples of Moon rocks showed a similar depletion of volatile elements.
Continue reading “Through The Nuclear Looking Glass: The Moon & The Bomb”
It’s that time again! This week’s Carnival of Space is hosted by Pamela Hoffman at the Everyday Spacer blog.
Click here to read Carnival of Space #496.
Continue reading “Carnival of Space #496”
SPACE VIEW PARK/KENNEDY SPACE CENTER, FL – For the first time in more than half a decade, a rocket came to life at NASA’s Kennedy Space Center when a SpaceX Falcon 9 breathed her first fire at historic pad 39A today, Sunday, Feb. 12 – successfully completing a critical static test firing of the first stage engines that opens the door to a launch to the space station next weekend for NASA.
The hot fire test generated a huge plume of smoke exhausting out the north side of the flame trench of Launch Complex 39A at approximately 4:30 p.m. EST, Feb. 12.
The hold down engine test with the erected rocket involved the ignition of all nine Merlin 1D first stage engines generating some 1.7 million pounds of thrust at pad 39A – which has been repurposed from its days as a shuttle launch pad.
The Merlin 1D engines fired for about 3 seconds while the two stage rocket was restrained on the pad.
SpaceX confirmed the test via social media shortly after it took place.
“First static fire test of Falcon 9 at historic launch complex 39A completed in advance of Dragon’s upcoming mission to the @Space_Station,” SpaceX tweeted in a very brief announcement.
I watched excitedly from a public viewing spot at Space View Park in Titusville as the exhaust plume grew quickly in size to a gigantic grey-white colored mushroom cloud of smoke and ash, heaving out the north side of the flame trench silent since the shuttle era.
Then just as quickly the smoke cloud dissipated completely within about 10 minutes leaving barely a trace of what we can expect to see soon.
Titusville offers a prime viewing location for anyone interested in traveling to the Florida Space Coast to see this Falcon 9 launch in person.
The test confirms that both the first stage engines and the rocket are suited for liftoff. Over the past few days, launch teams also tested the pad equipment, raised and lowered the rocket and conducted fit checks of the rocket at the pad.
The test had been delayed several days as technicians coped with issues until all was right to carry out the static fire test.
The positive outcome paves the path for a Falcon 9.Dragon blastoff as soon as next Saturday.
This marks the first time any rocket has stood on pad 39A and fired its engines since the retirement of NASA’s Space Shuttles in July 2011 on the STS-135 mission to the space station.
Liftoff of the Falcon 9 is slated for no earlier than next Saturday, 18 Feb 2017 on a critical cargo flight for NASA to deliver over two and a half tons of science and supplies to the six person crew living and working on the International Space Station (ISS).
The rocket – minus the payload comprising the Dragon cargo spacecraft – was rolled out of the SpaceX processing hangar at the perimeter fence and then up the incline to the top of pad 39A on Friday morning using a dedicated transporter-erector.
After the successful completion of the static fire test, the booster will be rolled back to the big processing hangar and the Dragon resupply ship will be integrated on top.
The historic NASA launch pad was formerly used to launch both America’s space shuttles and astronauts on Apollo/Saturn V moon landing missions.
Dragon will be loaded with more than 5500 pounds of equipment, gear, food, supplies and NASA’s Stratospheric Aerosol Gas Experiment III (SAGE III) ozone mapping science payload.
SpaceX was previously employing pad 40 on Cape Canaveral Air Force Station for Falcon 9 launches to the ISS as well as commercial launches.
But pad 40 suffered severe damage following the unexpected launch pad explosion on Sept 1, 2016 that completely destroyed a Falcon 9 and the $200 million Amos-6 commercial payload during a prelaunch fueling test.
An accident investigation revealed that a second stage helium tank burst due to friction ignition during the fueling test.
SpaceX modified the fueling procedures as a short term fix and is working on redesigning the second stage as a long term fix.
SpaceX is working to repair and refurbish pad 40. It is not known when it will be ready to resume launches.
Thus SpaceX has had to switch launch pads for near term future flights and press pad 39A into service much more urgently, speeding up the refurbishing and repurposing work which at last is sufficient to launch rockets again.
Pad 39A has lain dormant for launches for nearly six years since Space Shuttle Atlantis launched on the final shuttle mission STS 135 in July 2011.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
To radar imager Lance Benner at JPL in Pasadena, asteroid 2017 BQ6 resembles the polygonal dice used in Dungeons and Dragons. But my eyes see something closer to a stepping stone or paver you’d use to build a walkway. However you picture it, this asteroid is more angular than most imaged by radar.
It flew harmlessly by Earth on Feb. 7 at 1:36 a.m. EST (6:36 UT) at about 6.6 times the distance between Earth and the moon or some about 1.6 million miles. Based on 2017 BQ6’s brightness, astronomers estimate the hurtling boulder about 660 feet (200 meters) across. The recent flyby made for a perfect opportunity to bounce radio waves off the object, harvest their echoes and build an image of giant space boulder no one had ever seen close up before.
The images of the asteroid were obtained on Feb. 6 and 7 with NASA’s 230-foot (70-meter) antenna at the Goldstone Deep Space Communications Complex in California and reveal an irregular, angular-appearing asteroid:
“The radar images show relatively sharp corners, flat regions, concavities, and small bright spots that may be boulders,” said Lance Benner of NASA’s Jet Propulsion Laboratory in Pasadena, California, who leads the agency’s asteroid radar research program. “Asteroid 2017 BQ6 reminds me of the dice used when playing Dungeons and Dragons.”
2017 BQ6 was discovered on Jan. 26 by the NASA-funded Lincoln Near Earth Asteroid Research (LINEAR) Project, operated by MIT Lincoln Laboratory on the Air Force Space Command’s Space Surveillance Telescope at White Sands Missile Range, New Mexico.
Radar has been used to observe hundreds of asteroids. Even through very large telescopes, 2017 BQ6 would have appeared exactly like a star, but the radar technique reveals shape, size, rotation, roughness and even surface features.
To create the images, Benner conducted a controlled experiment on the asteroid, transmitting a signal with well-known characteristics to the object and then, by comparing the echo to the transmission, deduced its properties. According to NASA’s Asteroid Radar Research site, measuring how the echo power spreads out over time along with changes in its frequency caused by the Doppler Effect (object approaching or receding from Earth), provide the data to construct two-dimensional images with resolutions finer than 33 feet (10 meters) if the echoes are strong enough.
In late October 2016, the number of known near-Earth asteroids topped 15,000 with new discoveries averaging about 30 a week. A near-Earth asteroid is defined as a rocky body that approaches within approximately 1.3 times Earth’s average distance to the Sun. This distance then brings the asteroid within roughly 30 million miles (50 million km) of Earth’s orbit. To date, astronomers have already discovered more than 90% of the estimated number of the large near-Earth objects or those larger than 0.6 miles (1 km). It’s estimated that more than a million NEAs smaller than 330 feet (100 meters) lurk in the void. Time to get crackin’.
A renewed era of space exploration is underway. Compared to the Space Race of the 20th century, which was characterized by two superpowers locked in a game of “getting there first”, the new era is defined predominantly by cooperation and open participation. One way in which this is evident is the role played by “citizen scientists” and amateur astronomers in exploration missions.
Consider the recently-released short film titled “A Journey to Jupiter” by Peter Rosen – a photographer and digital artist in Stockholm, Sweden. Using over 1000 images taken by amateur planetary photographers from around the world, this film takes viewers on a virtual journey to the Jovian planet, showcasing its weather patterns and dynamic nature in a way that is truly inspiring.
The images that went into making this video were collected by over 91 amateur astronomers over the course of three and a half months (between December 19th, 2014 and March 31st, 2015). After Rosen collected them, he and his associates (Christoffer Svenske and Johan Warell) then spent a year remapping them into cylindrical projections. Rosen then added color corrections, and stitched all the images into a total of 107 maps.
Much like fast-motion videos that illustrate weather patterns on Earth, or the passage of the stars across the night sky, the end result of was a film that shows the motions of Jupiter’s cloud belts and its Great Red Spot in high-resolution. Some 250 revolutions of the planet are illustrated, including from the equatorial band, the south pole, and the north pole.
As Rosen told Universe Today via email, this project was the latest in a lifelong pursuit of making astronomy accessible to the public:
“I have been into Astronomy since I was a teenager in the early 1970’s and immediately I got a passion for astrophotography, and more specifically, photographing the planets. I see astronomy as a life-long passion, so it is quite normal to strive for an evolution in what you do. I had an idea growing slowly for some years that it should be possible to animate the cloud belts of Jupiter and reveal the intricate dynamics of its flows, not just taking still pictures that might point to the changes in the structures but without the obvious visual dynamics of an animation.”
“A Journey to Jupiter” was also Rosen’s contribution to the Mission Juno Pro-Amateur Collaboration Project, of which he is part. Established by Glenn Orton of NASA’s Jet Propulsion Laboratory, this effort is one of several that seeks to connect amateurs and professionals in support of space exploration. Back in May of 2016, this group met in Nice, France, for a workshop dedicated to projects and techniques related to Jupiter observations.
Among other items discussed was the limitations that missions like Juno have to deal with. While it is capable of taking very-high resolution images of Jupiter, these images are highly specific in nature. And before a team of mission scientists are able to color-correct them and stitch them together to create panoramas, etc., they are not always what you might call “visually stunning”.
However, Earth-based observatories are not hampered by this restriction, and can take multiple images of a planet over time that capture it as a whole. And thanks to the availability of sophisticated telescopes and imaging software, amateur astronomers are capable of making important contributions in this regard. And far from these being strictly for scientific purposes, there is also the added benefit of public engagement.
“This has been a very technical and scientifically correct project,” said Rosen, “but as a photographer and digital artist I also wanted to create a work of art that would inspire and appeal to people who are fascinated by the universe but who are not necessarily into astronomy.”
Of course, this does not detract from the scientific value that this film has. For example, it showcases the turbulent nature of Jupiter’s atmosphere in a way that is scientifically accurate. Hence why Ricardo Hueso Alonso – a physicist at the University of Basque Country and a member of the Planetary Virtual Observatory and Laboratory (PVOL) – plans to use the maps to measure Jupiter’s wind speeds at different latitudes.
On top of its artistic and scientific merit, “A Journey to Jupiter” also serves as a testament to the skill and capability of the today’s amateur astronomers and planetary photographers. And of course, it draws attention to the efforts of space missions such as Juno, which is currently skimming the clouds of Jupiter to obtain the most comprehensive information about the planet’s atmosphere and magnetic field to date.
Not surprisingly, this is not the first film by Rosen that combines scientific accuracy and fast-motion visuals. The short film Voyager 3, released back in June of 2014, was an homage by Rosen and six other Swedish amateur astronomers to the Voyager 1 mission. As the probe made its 28-day final approach to Jupiter in 1979, it snapped what were the most detailed images of Jupiter at the time.
These images helped to improve our understanding of the gas giant, its atmosphere, and its moons. Among other things, hey revealed the turbulent nature of Jupiter’s atmosphere, and that the Great Red Spot had changed color since the Pioneer 10 and 11 missions had flown by in 1973 and 74. Produced 35 years later, Voyager 3 was an attempt to recreate this historic event using images taken by Swedish amateur astronomers using their own ground-based telescopes.
Over the course of 90 days, Rosen and his colleagues captured one million frames of Jupiter, which resulted in 560 still images of the planet. These were then stitched together using a series of software programs (Winjupos, Photoshop CS6, Fantamorph, and StarryNightPro+) to create a simulation that gives the impression of a probe approaching the planet – i.e. like a third Voyager mission, hence the name of the film.
“As Jupiter was ideally positioned high in the sky in 2013-2014 for us living far up in the northern hemisphere, I decided that it was the right moment to give it a try, so I contacted 6 other amateurs on our local forum that shared my passion for the planets,” Rosen said. “We photographed Jupiter as often as we could during a 3-month period and I took care of the processing of the images which took me a total of 6 months.”
It is an exciting time to be alive. Not only are a greater number of national space agencies taking part in the exploration of the Solar System; but more than ever, citizen scientists, amateurs and members of the general public are able to participate in a way that was never before possible.
To view more work by Peter Rosen, be sure to check out his page at Vimeo.
Further Reading: NASA
KENNEDY SPACE CENTER, FL – The first SpaceX Falcon 9 rocket ever to grace historic launch pad 39A at NASA’s Kennedy Space Center in Florida was erected this afternoon, Friday, Feb. 10, to prepare the booster for a critical static fire sometime Saturday, and a launch to the space station next weekend – if all goes well.
This marks the first time any rocket has stood on pad 39A since the retirement of NASA’s Space Shuttles in July 2011.
Liftoff of the Falcon 9 is slated for no earlier than next Saturday, 18 Feb 2017 on a critical cargo flight for NASA to deliver over two and a half tons of science and supplies to the six person crew living and working on the International Space Station (ISS).
The rocket – minus the payload comprising the Dragon cargo spacecraft – was rolled out of the SpaceX processing hangar at the perimeter fence and then up the incline to the top of pad 39A this morning using a dedicated transporter-erector.
The booster was then hoisted into launch position this afternoon.
The scene was viewed by spectators including my space journalist colleague Jeff Seibert.
The historic NASA launch pad was formerly used to launch both America’s space shuttles and astronauts on Apollo/Saturn V moon landing missions.
SpaceX CEO Elon Musk also posted a photo on instagram with this caption:
“Falcon 9 rocket now vertical at Cape Canaveral on launch complex 39-A. This is the same launch pad used by the Saturn V rocket that first took people to the moon in 1969. We are honored to be allowed to use it.”
After the successful completion of the static fire test, the booster will be rolled back to the big processing hangar and the Dragon resupply ship will be integrated on top.
During the brief static fire test, all 9 Merlin 1D first stage engines are ignited for a few seconds to confirm they and the rocket are suited for liftoff while hold down clamps restrain the rocket on the pad.
Dragon will be loaded with more than 5500 pounds of equipment, gear, food, supplies and NASA’s Stratospheric Aerosol Gas Experiment III (SAGE III) ozone mapping science payload.
Pad 39A has lain dormant for launches for nearly six years since Space Shuttle Atlantis launched on the final shuttle mission STS 135 in July 2011.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Whoever coined the phrase “it’s a small world” obviously never tried to travel around it! In truth, the planet’s dimensions are quite impressive, and determining just how big it is took many thousands of years. From astronomers determining that Earth was in fact round (and not a flat disc, cube or ziggurat), to the first successful attempts at circumnavigation, our estimates have changed over time.
And in the era of modern astronomy, improvements in instrumentation, methodology, and the ability to see Earth from space have certainly helped. According to modern estimates, the surface area of the Earth is approximately 510 million square km (5.1 x 108 km2) or 196,900,000 square miles. Determining this was not only a matter of ascertaining Earth’s dimensions, but also its proper shape.
For starters, and contrary to what scientists have believed since classical antiquity, Earth is not a perfect sphere. Since the 17th and 18th centuries – thanks to improvements made in the field of astronomy and geodesy (a branch of mathematics dealing with the measurement of the Earth) – scientists have understood that the Earth is actually a flattened sphere.
This is what is known as an “oblate spheroid”, which is a sphere that is wider at its horizontal axis than it is at its vertical axis. According to the 2004 Working Group of the International Earth Rotation and Reference Systems Service (IERS), Earth experiences a flattening of 0.0033528 at the poles. This flattening is due to Earth’s rotational velocity – a rapid 1,674.4 km/h (1,040.4 mph) – which causes the planet to bulge at the equator.
Because of this, the diameter of the Earth at the equator is about 43 kilometers (27 mi) larger than the pole-to-pole diameter. The latest measurements indicate that the Earth has an equatorial diameter of 12,756 km (7926 mi), and a polar diameter of 12713.6 km (7899.86 mi). This is true for other planets in the Solar System that have rapid rotations (like Jupiter and Saturn), and even stars like the rapidly-spinning Altair.
Given its particular shape, calculating the Earth’s surface area requires a specific equation. Whereas determining the surface area of a sphere is a simple matter of multiplying pi by four, and these by the square of its radius (4 x 3.14159… x r²), to calculate the surface area of an oblate spheroid – where the distance from the center to a pole (c) is less than its semi-axis (a) – the following equation has to come into play:
Whereas S equals the surface area, c represents the distance from the center to a pole, and a represents the semi-axis, e represents the eccentricity. Naturally, Earth’s surface area can also be subdivided between water and land segments (aka. oceans or continental crust).
And since 70% of the Earth’s surface is covered by water, that works out to 361 million km² (139.4 million mi²). Earth’s continents, on the other hand, cover the remaining 149 million km² (57.5 or million mi²). This is a phenomena unique to Earth (at least in our Solar System) since no other Solar planet has liquid water covering a significant amount of its surface.
Compared to the other planets of the Solar System, Earth ranks somewhere in the middle. Of the terrestrial planets (i.e. Mercury, Venus, Earth and Mars) it is the largest. However, when compared to the gas giants (Jupiter, Saturn, Uranus and Neptune) it comes in dead last! Let’s see just how Earth stacks up against these other worlds…
Mercury is the smallest planet in our Solar System (ever since the 2006 IAU decision that designated Pluto as “dwarf planet”). It has a surface area of 7.48 x 107 km2, which is only about 15% of Earth’s surface area. Venus is similar in size to Earth, hence why it has earned the title of “Earth’s Sister Planet”. Consistently, Venus has a surface area of 4.6 x 108 km2, which is roughly 90% of Earth’s.
Mars is also a small planet, the second smallest in our Solar System. This is evident in Mars’ diminutive surface area of 1.45 x 108 km2, which is roughly 28% that of Earth’s. Moving to the outer Solar System, it is quickly made apparent that all of the gas giants have the four planets of the inner Solar System beat (at least in a size contest)!
Jupiter is the largest planet in our Solar System, with a surface area of 6.14 x 1010 km2 – which is about 122 times greater than the surface area of Earth! Saturn is the second largest planet in our Solar System and has a surface area of 4.27 x 1010 km2 – which is roughly 83.7 times that of Earth.
As for the “ice giants”, Uranus has a surface area of 8.1156 x 109 km2 (15.91 times that of Earth) while Neptune has a slightly smaller surface area of 7.618 x 109 km2, which is close to 15 times that of Earth.
All told, Earth is relatively spacious place, as terrestrial bodies go. But the amount of surface that we humans can actually live on is rather limited. Once you subtract all the space that’s occupied by water, you begin to see that the world may be a little on the smallish side after all.
We have written many interest articles about the Earth for Universe Today. Here’s What is the Diameter of Earth?, How Strong is the Force of Gravity on Earth?, How Much Does the Earth Way?, How Fast Does the Earth Rotate?, 1o Interesting Facts About Planet Earth, What is the Earth’s Average Temperature?, and Why Does the Earth Rotate?
Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.
We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.
Sources:
Welcome back to Constellation Friday! Today, in honor of the late and great Tammy Plotner, we will be dealing with the “Centaur”, the Centaurus constellation!
In the 2nd century CE, Greek-Egyptian astronomer Claudius Ptolemaeus (aka. Ptolemy) compiled a list of all the then-known 48 constellations. This treatise, known as the Almagest, would be used by medieval European and Islamic scholars for over a thousand years to come, effectively becoming astrological and astronomical canon until the early Modern Age.
One of these is the famous Centaur of classical antiquity, otherwise known as the constellation Centaurus. As one of the 48 constellation included in the Almagest, it is now one of the 88 modern constellations recognized by the IAU. Located in the southern sky, this constellation is bordered by the Antlia, Carina, Circinus, Crux, Hydra, Libra, Lupus, Musca, and Vela constellations.
In classic Greco-Roman mythology, Centaurus is often associated with Chiron the Centaur – the wise half-man, half-horse who was a teacher to both Hercules and Jason and the son of the Titan king Cronus and the sea nymph Philyra. According to legend, Cronus seduced the nymph, but they were interrupted by Cronus’ wife Rhea. To evade being caught in the act, Cronus turned himself into a horse.
As a result, Philyra gave birth to a hybrid son. He died a tragic death in the end, having been accidentally struck by one of Heracles’ poisoned arrows. As an immortal god, he suffered terrible pains but could not die. Zeus eventually took pity on the centaur and released him from immortality and suffering, allowing him to die, and placed him among the stars.
It is believed that the constellation of Sagitta is the arrow which Chiron fired towards Aquila the Eagle to release the tortured Prometheus. The nearby constellation of Lupus the Wolf may also signify an offering of Hercules to Chiron – whom he accidentally poisoned. Just as Virgo above represents the maid placed in the sky as a sign of pity for the Centaur’s plight.
The first recorded examples of Centaurus date back to ancient Sumeria, where the constellation was depicted as the Bison-man (MUL.GUD.ALIM). This being was depicted in one of two ways – either as a four-legged bison with a human head, or as a creature with a human head and torso attached to the rear legs of a bison or bull. In the Babylonian pantheon, he was closely associated with the Sun god Utu-Shamash.
The Greek depiction of the constellation as a centaur is where its current name comes from. Centaurus is usually depicted as sacrificing an animal, represented by the constellation Lupus, to the gods on the altar represented by the Ara constellation. The centaur’s front legs are marked by two of the brightest stars in the sky, Alpha and Beta Centauri (aka. Rigil Kentaurus and Hadar), which also serve as pointers to the Southern Cross.
In the 2nd century AD, Ptolemy catalogued 37 stars in the constellation and included it as one of the 48 constellations listed in the Almagest. In 1922, it was included in the 88 modern constellations recognized by the International Astronomical Union (IAU).
Centaurus contains 11 main stars, 9 bright stars and 69 stars with Bayer/Flamsteed designations. Its brightest star – Alpha Centauri (Rigel Kentaurus) – is the Solar System’s closest neighbor. Located just 4.365 light years from Earth, this multiple star system consists of a yellow-white main sequence star that belongs to the spectral type G2V (Alpha Centauri A), and a spectral type K1V star (Alpha Centauri B).
Alpha Centauri A, the brightest component in the system, is the fourth brightest individual star (behind Arcturus) in the night sky, B is the 21st individual brightest star in the sky. Taken together, however, they are brighter than Arcturus, and rank third among the brightest star system (behind Sirius and Canopus). The two stars are believed to be roughly the same age – ~4.85 billion years old – and are close in mass to our Sun.
Proxima Centauri, a red dwarf system (spectral class M5Ve or M5Vie), if often considered to be a third member of this star system. Located about 0.24 light years from the binary pair (and 4.2 light years from Earth), this star system was confirmed in 2016 to be home to the closest exoplanet to Earth (Proxima b).
Then there’s Beta Centauri, a blue-white giant star (spectral class B1III) located 348.83 light years from Earth that is the tenth brightest star in the sky. The star’s traditional names (Hadar or Agena), are derived from the Arabic words for “ground” and “the knee”, respectively. This multiple star system consists of Hadar A, a spectroscopic binary of two identical stars, while Hadar B orbits the primary pair with a period of at least 250 days.
Next up is Theta Centauri (aka. Menkent), an orange K-type giant (spectral class K0IIIb) that is located approximately 60.9 light years from Earth. Its traditional name, which comes from its location in the constellation, translates to “shoulder of the Centaur” in Arabic.
And then there’s Gamma Centauri (Muhlifain), a binary star system located 130 light years from Earth which is composed of two stars belonging to the spectral type A0. It’s name is translated from Arabic and means “two things”, or the “swearing of an oath”, which appears to be a case of name-transfer from Muliphein, a star located in the Canis Majoris constellation.
The constellation is also home to many Deep Sky Objects. For instance, there is the Centaurus A galaxy, the fifth brightest galaxy in the sky and one of the closest radio galaxies to the Solar System (between 10 and 16 million light years distant). The galaxy has an apparent visual magnitude of 6.84 and is believed to contain a supermassive black hole at its center.
Centaurus A’s brightness is attributed to the intense burst of star formation going on inside it, which is believed to be the result of it undergoing a collision with a spiral galaxy. Centaurus A is located at the center of the Centaurus A subgroup of the Centaurus A/M83 Group of galaxies, which includes the Southern Pinwheel Galaxy (aka. Messier 83, M83).
Then there’s the famous Omega Centauri globular cluster, one of the brightest globular clusters in the Milky Way. Located approximately 15,800 light years distant, this cluster is bright enough to be visible to the naked eye. Originally listed as a star by Ptolemy in the Almagest, the cluster’s true nature was not discovered until John Herschel studied it in the early 19th century.
Next up is NGC 4945, one of the brightest galaxies in the Centaurus A/M83 group, and the second brightest galaxy in the Centaurus A subgroup. The spiral galaxy is approximately 11.7 million light years distant and has an active Seyfert II nucleus, which could be due to the presence of a supermassive black hole at its center.
The galaxy NGC 4650A is also located in Centaurus, some 130 million light years from Earth. This galaxy is one of only 100 polar-ring galaxies known to exist, which are so-named because their outer ring of stars and gas rotate over the poles of the galaxy. These rings are believed to have formed from the gravitational interaction of two galaxies, or from a collision with a smaller galaxy in the past.
The Blue Planetary nebula (aka. the Southerner), is a bright planetary nebula in Centauru, approximately 4,900 light years distant. With an apparent visual magnitude of 8.5, it is the brightest planetary nebula in the far southern region of the sky and and can be observed in a small telescope.
Centaurus is one of the largest constellations in the night sky – covering over 1000 square degrees – and the brightest in the southern hemisphere. For observers located at latitudes between +30° and -90°, the entire constellation is visible and the northern portion of the constellation can be spotted easily from the northern hemisphere during the month of May.
For the unaided southern skies observer, the constellation of Centaurus holds a gem within its grasp – Omega Centauri (NGC 5139). But of course, this object isn’t a star – despite being listed on the catalogs as its Omega star. It’s a globular cluster, and the biggest and brightest of its kind known to the Milky Way Galaxy. Though visible to the naked eye, it is best observed through a telescope or with binoculars.
This 18,300 light-year beauty contains literally millions of stars with a density so great at its center the stars are less than 0.1 light year apart. It is possible Omega Centauri may be the remains of a galaxy cannibalized by our own. Even to this present day, something continues to pull at NGC 5139’s stars… tidal force? Or an unseen black hole?
Now, hop down to Alpha. Known as Rigil Kentaurus, Rigil Kent, or Toliman, is the third brightest star in the entire night sky and the closest star system to our own solar system. To the unaided eye it appears a single star, but it’s actually a binary star system. Alpha Centauri A and Alpha Centauri B are the individual stars and a distant, fainter companion is called Proxima Centauri – a red dwarf that is the nearest known star to the Sun.
Oddly enough, Proxima Centauri is also a visual double, which is assumed to be associated with Centaurus AB pair. Resolution of the binary star Alpha Cen AB is too close to be seen by the naked eye, as the angular separation varies between 2 and 22 arc seconds, but during most of the orbital period, both are easily resolved in binoculars or small telescopes.
Then stop for a moment to take a look at Beta Centauri. Beta Centauri is well-known in the Southern Hemisphere as the inner of the two “Pointers” to the Southern Cross. A line made from the other pointer, Alpha Centauri, through Beta Centauri leads to within a few degrees of Gacrux, the star at the top of the cross. Using Gacrux, a navigator can draw a line with Acrux to effectively determine south.
But, that’s not all! Hadar is also a very nice double star, too. The blue-white giant star primary is also a spectroscopic binary, accompanied by a widely spaced companion separated from the primary by 1.3″. Or try Gamma Centauri! Muhlifain has an optical companion nearby, but check it out in the telescope… it’s really two spectral type A0 stars each of apparent magnitude +2.9!
For binoculars or telescopes, hop on over to Centaurus A. This incredible radio source galaxy is one of the closest to Earth and also the fifth brightest in the sky. When seen through an average telescope, this galaxy looks like a lenticular or elliptical galaxy with a superimposed dust lane, and oddity first noted in 1847 by John Herschel.
The galaxy’s strange morphology is generally recognized as the result of a merger between two smaller galaxies and photographs reveal a jet of material streaming from the galactic core. Although we cannot see it, there may be a supermassive black hole at the center of the galaxy is responsible for emissions in the X-ray and radio wavelengths!
For binoculars and rich field telescopes, head towards the Crux border and center on Lambda Centauri for open cluster, IC2944. Also known on some observing lists as Caldwell 100, this scattered star cluster contains about 30 stellar members and some faint nebulosity. About 2 degrees southwest of Beta you’ll find another pair of open clusters, NGCs 5281 and 5316. Or try your hand just about a degree west of Alpha for open cluster, NGC5617. These last three are far more rich in stars and photon satisfying!
Centaurus has been known to human astronomers since the Bronze Age and has gone through some changes since that time. But even after thousands of years’ time, the Centaur is still hunting in the night sky! And for those who love viewing classic constellations and bright objects, it still provides viewing opportunities that are bound to dazzle the eyes and inspire the mind!
We have written many interesting articles about the constellation here at Universe Today. Here is What Are The Constellations?, What Is The Zodiac?, and Zodiac Signs And Their Dates.
Be sure to check out The Messier Catalog while you’re at it!
For more information, check out the IAUs list of Constellations, and the Students for the Exploration and Development of Space page on Canes Venatici and Constellation Families.
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Venus is often described as being hell itself, because of its crushing pressure, acidic atmosphere, and extremely high temperatures. Dealing with any one of these is a significant challenge when it comes to exploring Venus. Dealing with all three is extremely daunting, as the Soviet Union discovered with their Venera landers.
Actually, dealing with the sulphuric rain is not too difficult, but the heat and the pressure on the surface of Venus are huge hurdles to exploring the planet. NASA has been working on the Venus problem, trying to develop electronics that can survive long enough to do useful science. And it looks like they’re making huge progress.
Scientists at the NASA Glenn Research Centre have demonstrated electronic circuitry that should help open up the surface of Venus to exploration.
“With further technology development, such electronics could drastically improve Venus lander designs and mission concepts, enabling the first long-duration missions to the surface of Venus,” said Phil Neudeck, lead electronics engineer for this work.
With our current technology, landers can only withstand surface conditions on Venus for a few hours. You can’t do much science in a few hours, especially when weighed against the mission cost. So increasing the survivability of a Venus lander is crucial.
With a temperature of 460 degrees Celsius (860 degrees Fahrenheit), Venus is almost twice as hot as most ovens. It’s hot enough to melt lead, in fact. Not only that, but the surface pressure on Venus is about 90 times greater than Earth’s, because the atmosphere is so dense.
To protect the electronics on previous Venus landers, they have been contained inside special vessels designed to withstand the pressure and temperature. But these vessels add a lot of mass to the mission, and make sending landers to Venus a very expensive proposition. So NASA’s work on robust electronics is super important when it comes to exploring Venus.
The team at the Glenn Research Centre has developed silicon carbide semiconductor integrated circuits (Si C IC) that are extremely robust. Two of the circuits were tested inside a special chamber designed to precisely reproduce the conditions on Venus. This chamber is called the Glenn Extreme Environments Rig (GEER.)
GEER is a special chamber that can recreate the conditions on any body in our Solar System. It’s an 800 Litre (28 cubic foot) chamber that can simulate temperatures up to 500° C (932° F), and pressures from near-vacuum to over 90 times the surface pressure of Earth. GEER can also simulate exotic atmospheres with its precision gas-mixing capabilities. It can mix very specific quantities of gases down to parts per million accuracy. For these tests, that means the unit had to reproduce an accurate recipe of CO2, N2, SO2, HF, HCl, CO, OCS, H2S, and H2O, down to very tiny quantities. And the tests were a success.
“We demonstrated vastly longer electrical operation with chips directly exposed — no cooling and no protective chip packaging — to a high-fidelity physical and chemical reproduction of Venus’ surface atmosphere,” Neudeck said. “And both integrated circuits still worked after the end of the test.”
In fact, the two circuits not only functioned after the test was completed, but they withstood Venus-like conditions for 521 hours. That’s more than 100 times longer than previous demonstrations of electronics designed for Venus missions.
The circuits themselves were originally designed to operate in the extremely high temperatures inside aircraft engines. “This work not only enables the potential for new science in extended Venus surface and other planetary exploration, but it also has potentially significant impact for a range of Earth relevant applications, such as in aircraft engines to enable new capabilities, improve operations, and reduce emissions,” said Gary Hunter, principle investigator for Venus surface electronics development.”
The chips themselves were very simple. They weren’t prototypes of any specific electronics that would be equipped on a Venus lander. What these tests showed is that the new Silicon Carbide Integrated Circuits (Si C IC) can withstand the conditions on Venus.
A host of other challenges remains when it comes to the overall success of a Venus lander. All of the equipment that has to operate there, like sensors, drills, and atmospheric samplers, still has to survive the thermal expansion from exposure to extremely high temperature. Robust new designs will be required in many cases. But this successful test of electronics that can survive without bulky, heavy, protective enclosures is definitely a leap forward.
If you’re interested in what a Venus lander might look like, check out the Venus Sail Rover concept.
