This week the Virtual Star Party crossed off one of the items on my bucket list: star trails. During the star party, Cory Schmitz kept the shutter going on his Canon 5D and took a series of images of the stars turning around the celestial North Pole. Once the timelapse was complete, we had a beautiful set of star trails, showing how much the Earth rotates during an hour.
The Upside Down AstronomerPaul Stewart jumped in with an amazing view of the Sun from New Zealand. We could see prominences and granules on the surface of the Sun, especially when he zoomed in.
And while all this was going on, we also got a chance to see beautiful clusters, nebulae and galaxies.
We hold the Virtual Star Party every Sunday night as a live Google+ Hangout on Air. You can find out more information from the Virtual Star Party. We start when it gets dark on the West Coast of North America.
The Cygnus cargo spacecraft is just a few feet away from the International Space Station's Canadarm2 during rendezvous and berthing on Sept 29, 2013. Credit: NASA
The Cygnus cargo spacecraft is just a few feet away from the International Space Station’s Canadarm2 during rendezvous and berthing on Sept 29, 2013. Credit: NASA
Updated – See Falcon 9 launch video below[/caption]
Today (Sept. 29) was a doubly historic day for private spaceflight! And a boon to NASA as well!
Early this morning the Orbital Sciences Cygnus commercial cargo ship docked at the International Space Station (ISS) speeding along some 250 miles (400 km) overhead in low Earth orbit.
Barely a few hours later the Next Generation commercial SpaceX Falcon 9 rocket soared to space on a demonstration test flight from the California coast carrying a Canadian satellite to an elliptical earth orbit.
These missions involved the dramatic maiden flights for both Cygnus and the upgraded Falcon 9.
And both were high stakes endeavors, with literally billions of dollars and the future of commercial spaceflight, as well as the ISS, on the line. Their significance cannot be overstated!
Falcon 9 lifts off from SpaceX’s pad at Vandenberg on Sept 29, 2013, carrying Canada’s CASSIOPE satellite to orbit. Credit: SpaceX
Both Cygnus and Falcon 9 were developed with seed money from NASA in a pair of public-private partnerships between NASA and Orbital Sciences and SpaceX under NASA’s COTS commercial transportation initiative aimed at fostering the development of America’s private space industry to deliver critical and essential supplies to the ISS.
The powerful new Falcon 9 will also be used to send cargo to the ISS.
America completely lost its capability to send humans and cargo to the ISS when NASA’s space shuttles were retired in 2011. Orbital Sciences and SpaceX were awarded NASA contracts worth over $3 Billion to restore the unmanned cargo resupply capability over 20 flights totally.
The Cygnus spacecraft put on a spectacular space ballet – and was no worse for the wear after its docking was delayed a week due to an easily fixed communications glitch.
The Cygnus commercial resupply craft is installed by the Canadarm2 to the Harmony node. Credit: NASA TV
Cygnus is a privately developed resupply vessel built by Orbital Sciences Corp and Thales Alenia Space that is a crucial railroad to orbit for keeping the massive orbital lab complex well stocked with everyday essentials and science experiments that are the purpose of the ISS.
Cygnus was grappled in free drift by Expedition 37 space station astronauts Luca Parmitano and Karen Nyberg at about 7 a.m. EDT Sunday morning.
The pair were working at two robotics work stations from inside the Cupola and Destiny modules. They used the stations 57 foot long Canadarm2 to snare Cygnus at a distance of about 30 feet (10 meters). They gradually motioned the arm closer.
Running a bit ahead of schedule they successfully berthed Cygnus at the earth facing port of the Harmony module by about 8:44 a.m. EDT.
Cygnus was launched to orbit on its inaugural flight on Sept. 18 atop Orbital’s commercial Antares rocket from NASA’s Wallops Flight Facility on the Eastern shore of Virginia.
Hatches to Cygnus will be opened on Monday, Sept. 30 after completing leak checks.
“Today, with the successful berthing of the Orbital Sciences Cygnus cargo module to the ISS, we have expanded America’s capability for reliably transporting cargo to low-Earth orbit, “ said NASA Admisistrator Charles Bolden in a statement.
“It is an historic milestone as this second commercial partner’s demonstration mission reaches the ISS, and I congratulate Orbital Sciences and the NASA team that worked alongside them to make it happen.”
“Orbital joins SpaceX in fulfilling the promise of American innovation to maintain America’s leadership in space. As commercial partners demonstrate their new systems for reaching the Station, we at NASA continue to focus on the technologies to reach an asteroid and Mars,” said Bolden.
Cygnus delivers about 1,300 pounds (589 kilograms) of cargo, including food, clothing, water, science experiments, spare parts and gear to the Expedition 37 crew.
The upgraded SpaceX Falcon 9 blasted off from Space Launch Complex 4 at Vandenberg Air Force Base in California at 9 a.m. PDT (12 p.m. EDT).
Here’s a video of the launch:
It successfully deployed Canada’s 1,060 pound (481 kg) Cascade, Smallsat, and Ionospheric Polar Explorer (CASSIOPE) weather satellite and several additional small satellites.
This powerful new version of the Falcon 9 dubbed v1.1 is powered by a cluster of nine of the new Merlin 1D engines that are about 50% more powerful compared to the standard Merlin 1C engines and can therefore boost a much heavier cargo load to the ISS and beyond.
The next generation Falcon 9 is a monster. It’s much taller than a standard Falcon 9 – some 22 stories vs. 13.
It could launch from Cape Canaveral as early as this Fall.
Learn more about Cygnus, Antares, SpaceX, Curiosity, Mars rovers, MAVEN, Orion, LADEE and more at Ken’s upcoming presentations
Oct 3: “Curiosity, MAVEN and the Search for Life on Mars – (3-D)”, STAR Astronomy Club, Brookdale Community College & Monmouth Museum, Lincroft, NJ, 8 PM
Oct 8: NASA’s Historic LADEE Lunar & Antares/Cygnus ISS Rocket Launches from Virginia”; Princeton University, Amateur Astronomers Assoc of Princeton (AAAP), Princeton, NJ, 8 PM
Antares rocket lifts off at 10:58 a.m. EDT Sept 18 with commercial Cygnus cargo resupply ship bound for the International Space Station (ISS) from Mid-Atlantic Regional Spaceport Pad-0A at NASA’s Wallops Flight Facility in Virginia. Credit: Ken Kremer (kenkremer.com)Antares and Cygnus streak to space and the ISS from NASA Wallops on Sept. 18, 2013. Credit: Ken Kremer (kenkremer.com)
Opportunity starts scaling Solander Point See the tilted terrain and rover tracks in this look-back mosaic view from Solander Point peering across the vast expanse of huge Endeavour Crater. Moasic assembled from navcam raw images taken on Sol 3431 (Sept.18, 2013). Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer - kenkremer.com
Opportunity starts scaling Solander Point – her 1st mountain climbing goal
See the tilted terrain and rover tracks in this look-back mosaic view from Solander Point peering across the vast expanse of huge Endeavour Crater. Opportunity will ascend the mountain looking for clues indicative of a Martian habitable environment. This navcam camera mosaic was assembled from raw images taken on Sol 3431 (Sept.18, 2013). Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer (kenkremer.com). See the complete panoramic view below[/caption]
NASA’s intrepid Opportunity rover has begun an exciting new phase in her epic journey – the ascent of Solander Point, the first mountain she will ever climb, after roving the Red Planet for nearly a decade. See the rovers tilted look-back view in our Sol 3431 mosaic above.
Furthermore, ground breaking discoveries providing new clues in search of the chemical ingredients required to sustain life are sure to follow as the rover investigates intriguing stratographic deposits distributed amongst Solander’s hills layers.
Why ? Because NASA’s powerful Mars Reconnaissance Orbiter (MRO) circling overhead has also recently succeeded in collecting “really interesting” new high resolution survey scans of Solander Point! Read my prior pre-survey account – here.
So says Ray Arvidson, the mission’s deputy principal scientific investigator, in an exclusive Opportunity news update to Universe Today. The new MRO data are crucial for targeting the rover’s driving in coming months.
After gaining approval from NASA, engineers successfully aimed the CRISM mineral mapping spectrometer aboard MRO at Solander Point and captured reams of new high resolution measurements that will inform the scientists about the mineralogical make up of Solander.
“CRISM data were collected,” Arvidson told Universe Today.
“They show really interesting spectral features in the [Endeavour Crater] rim materials.”
Opportunity starts scaling Solander Point – her 1st mountain climbing goal
See the tilted terrain and rover tracks in this look-back panoramic view from Solander Point peering across the vast expanse of huge Endeavour Crater. Opportunity will ascend the mountain looking for clues indicative of a Martian habitable environment. This navcam camera mosaic was assembled from raw images taken on Sol 3431 (Sept.18, 2013). Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer (kenkremer.com).
Solander Point is an eroded ridge located along the western rim of huge Endeavour Crater where Opportunity is currently located.
“Opportunity is on the bench at the tip of Solander Point,” Ray Arvidson told Universe Today exclusively. Arvidson is the mission’s deputy principal scientific investigator from Washington University in St. Louis, Mo.
At the bench, the long lived rover has begun scaling Solander in search of science and life giving sun.
“The CRISM data are being discussed by the MER [Mars Exploration Rover] Team this week,” Arvidson told me.
And it will take some time to review and interpret the bountiful new spectral data and decide on a course of action.
“For the CRISM data analysis we will have the MER Team see the results and agree.”
Expect that analysis to take a “couple of weeks” said Arvidson.
The new CRISM survey from Mars orbit will vastly improve the spectral resolution – from 18 meters per pixel down to 5 meters per pixel.
Above is the Pancam panorama acquired on sol 3375 when Opportunity was still approaching Solander Point. On it I have plotted the subsequent drives along the east side of the point, and the location on the contact as of September 18. The approximate places where we need to be by later this fall are shown here for anyone following along. It’s a new unexplored land with new scenes. Caption and Credit: NASA/JPL/Larry Crumpler
Another important point about ‘Solander Point’ is that it also offers northerly tilted slopes that will maximize the power generation during Opportunity’s upcoming 6th Martian winter.
In order to survive those Antarctic like, ‘bone chilling” winter temperatures on the Red Planet and continue with her epic mission, the engineers must drive the rover so that the solar wings are pointed favorably towards the sun.
And don’t forget that winter’s last six full months – that’s twice as long on Mars as compared to Earth.
The daily solar power output has been declining as Mars southern hemisphere enters late fall.
In the above Navcam panorama acquired on mid-morning on September 18 (sol 3431), you can see the contact between the younger Burns Formation sulfate-rich sands on the right and the older rocks of Endeavour crater on the left. We will probably follow this contact for ways to the south before starting the climb next week. Caption and Credit: NASA/JPL/Larry Crumpler
After traversing several months across the crater floor from the Cape York rim segment to Solander, Opportunity arrived at the foothills of Solander Point.
Solander and Cape York are part of a long chain of eroded segments of the crater wall of Endeavour crater which spans a humongous 14 miles (22 kilometers) wide.
Solander Point may harbor deposits of phyllosilicate clay minerals – which form in neutral pH water – in a thick layer of rock stacks indicative of a past Martian habitable zone.
The science team is looking at the new CRISM measurements, hunting for signatures of phyllosilicate clay minerals and other minerals and features of interest.
“Opportunity is on the bench on the northwest side of the tip of Solander Point,” Arvidson explained.
Since pulling up to Solander, the robot has spent over a month investigating the bench surrounding the mountain to put it the entire alien Martian terrain in context for a better understanding of Mars geologic history over billions of years.
Eons ago, Mars was far warmer and wetter and more hospitable to life.
“The rover is finishing up work on defining the stratigraphy, structure, and composition of the bench materials.”
“We are working our way counterclockwise on the bench to reach the steep slopes associated with the Noachian outcrops that are part of the Endeavour rim,” Arvidson elaborated.
“Opportunity is slightly tipped to the north to catch the sun.”
“Probably this week we will direct the rover to head south along the western boundary between the bench and the rim materials, keeping on northerly tilts,” Arvidson told me.
How does the bench at Solander compare to other areas investigated at Endeavour crater, I asked.
“The Solander Bench looks like the bench we saw around Cape York and around Sutherland Point and Nobbys Head,” replied Arvidson.
Opportunity scans Solander Point from a slope at the northern tip as she circles around the surrounding bench. This navcam camera mosaic was assembled from raw images taken on Sol 3423 (Sept. 2013). Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer
The rover recently investigated an outcrop target called ‘Poverty Bush’. She deployed her 3 foot long (1 meter) robotic arm and collected photos with the Microscopic Imager (MI) and collected several days of spectral measurements with the Alpha Particle X-ray Spectrometer (APXS).
Thereafter she resumed driving to the west/northwest around Solander.
“On September 13, Opportunity finally landed on the bed rock of Solander Point,” wrote Larry Crumpler, a science team member from the New Mexico Museum of Natural History & Science, in his latest field report about the MER mission.
“The terrain right here is awesome,” according to Crumpler.
“There are several geologic units that are overlapping here. And Opportunity is sitting on the contact.”
“On the east side of the contact are rocks maybe a billion years older than those on the west side of the contact. This sort of age progression is what geologists look for when trying to understand the past by reading the rocks.”
“Opportunity is allowing us for the first time to do not only fundamental geographic exploration, but it is enabling on the ground geologic study of past climatic history on Mars,” notes Crumpler.
Today marks Opportunity’s 3441st Sol or Martian Day roving Mars – for what was expected to be only a 90 Sol mission.
Traverse Map for NASA’s Opportunity rover from 2004 to 2013
This map shows the entire path the rover has driven during more than 9 years and over 3431 Sols, or Martian days, since landing inside Eagle Crater on Jan 24, 2004 to current location at foothills of Solander Point at the western rim of Endeavour Crater. Rover is now ascending Solander. Opportunity discovered clay minerals at Esperance – indicative of a habitable zone. Credit: NASA/JPL/Cornell/ASU/Marco Di Lorenzo/Ken Kremer
So far she has snapped over 184,500 amazing images on the first overland expedition across the Red Planet.
Her total odometry stands at over 23.82 miles (38.34 kilometers) since touchdown on Jan. 24, 2004 at Meridiani Planum.
Meanwhile on the opposite side of Mars, Opportunity’s younger sister rover Curiosity is trekking towards gigantic Mount Sharp and just discovered water altered pebbles at the intriguing ‘Darwin’ outcrop.
And NASA is in the final stages of processing of MAVEN, the agencies next orbiter, scheduled to blast off from Cape Canaveral on Nov.18 – see my upcoming up close article.
Learn more about Curiosity, Mars rovers, MAVEN, Orion, Cygnus, Antares, LADEE and more at Ken’s upcoming presentations
Oct 3: “Curiosity, MAVEN and the Search for Life on Mars – (3-D)”, STAR Astronomy Club, Brookdale Community College & Monmouth Museum, Lincroft, NJ, 8 PM
Oct 8: NASA’s Historic LADEE Lunar & Antares/Cygnus ISS Rocket Launches from Virginia”; Princeton University, Amateur Astronomers Assoc of Princeton (AAAP), Princeton, NJ, 8 PM
NASA’s MAVEN Mars orbiter, chief scientist Prof. Bruce Jakosky of CU-Boulder and Ken Kremer of Universe Today inside the cleanroom at the Kennedy Space Center on Sept. 27, 2013. MAVEN launches to Mars on Nov. 18, 2013 from Florida. Credit: Ken Kremer/kenkremer.com
Comet ISON, photographed with a 3-inch (80mm) telescope on this morning Sept. 28 shows a circular green coma and short dust tail pointing northwest. Click to enlarge. Credit: Michael Jaeger
As NASA and the European Space Agency prepare their remote photojournalists – Mars Express, Mars Reconnaissance Orbiter and the Curiosity and Opportunity rovers – to capture photos of Comet ISON’s flyby of Mars early next week, amateur astronomers continue to monitor and photograph the comet from backyard observatories across the blue Earth. Several recent color photos show ISON’s bright head or nucleus at the center of a puffy, green coma. Green’s a good omen – a sign the comet’s getting more active as it enters the realm of the inner solar system and sun’s embrace.
Another great photo of the “greening” of Comet ISON taken on Sept. 24 with a 17-inch (43-cm) telescope. Click to enlarge. Credit: Damian Peach
Sunlight beating down on the comet’s nucleus (core) vaporizes dust-impregnated ice to form a cloud or coma, a temporary atmosphere of water vapor, dust, carbon dioxide, ammonia and other gases. Once liberated , the tenuous haze of comet stuff rapidly expands into a huge spherical cloud centered on the nucleus. Comas are typically hundreds of thousands of miles across but are so rarified you could wave your hand through one and not feel a thing. The Great Comet of 1811 sported one some 864,000 miles (1.4 million km) across, nearly the same diameter as the sun!
Among the materials released by solar heating are cyanogenand diatomic carbon. Both are colorless gases that fluoresce a delicious candy-apple green when excited by energetic ultraviolet light in sunlight.
Sounds like a plan. Newspaper clipping from 1910.
Cyanogen smells pleasantly of almonds, but it’s a poisonous gas composed of one atom each of carbon and nitrogen. Diatomic carbon or C2 is equally unpleasant. It’s a strong, corrosive acid found not only in comets but also created as a vapor in high-energy electric arcs. But nature has a way of taking the most unlikely things and fashioning them into something beautiful. If you’re concerned about the effects of cometary gas and dust on people, rest easy. They’re spread too thinly to touch us here on Earth. That didn’t stop swindlers from selling “comet pills” and gas masks to protect the public from poisoning during the 1910 return of Halley’s Comet. Earth passed through the tail for six hours on May 19 that year. Amazingly, those who took the pills survived … as did everyone else.
Comet ISON’s location and approximate appearance on October 1 seen from the Curiosity Rover. ISON will pass only 6.7 million miles (10.8 million km) from Mars on Tuesday Oct. 1. Stellarium
While Comet ISON is still too faint for visual observers to discern its Caribbean glow, that will change as it beelines for the sun and brightens. If you could somehow wish yourself to Mars in the next few days, I suspect you’d easily see the green coma through a telescope. The comet – a naked eye object at magnitude 2.5-3 – glows low in the northern sky from the Curiosity rover’s vantage point 4.5 degrees south of the Martian equator.
Comet Hale-Bopp shows off its bright dust tail and fainter, blue ion tail in early spring 1997. Credit: Bob King
I’ve noticed that when a comet reaches about 7th magnitude, the green coloration becomes apparent in 8-inch (20 cm) and larger telescopes. Bright naked eye comets often display multiple subtle colors that change chameleon-like over time. Dust tails, formed when sunlight pushes dust particles downwind from the coma, glow pale yellow. Gusty solar winds sweep back molecules from the coma into a second “ion” tail that glows pale blue from jazzed up carbon monoxide ions fluorescing in solar UV.
One of the highlights of seeing Comet L4 PANSTARRS through a small telescope was its brilliant, pea-like false nucleus glowing yellow from sunlit dust. The real comet nucleus – the actual comet – lies within the false nucleus and hidden by dust. Drawing: Bob King
During close encounters with the sun, millions of pounds of dust per day boil off a comet’s nucleus, forming a small, intensely bright, yellow-orange disk in the center of the coma called a false nucleus. Earlier this year, when Comet C/2011 L4 PANSTARRS emerged into the evening sky after perihelion, not only was its yellow tail apparent to binocular users but the brilliant false nucleus glowed a lovely shade of lemon in small telescopes.
With ISON diving much closer to the sun than L4 PANSTARRS, expect a full color palette in the coming weeks. While it may not be easy being green for Sesame Street’s Kermit the Frog, comets do it with aplomb.
Mud island off the coast of Gwadar imaged by NASA's EO-1 satellite on Sept. 26, 2013
On the afternoon of Tuesday September 24, 2013, a 7.7-magnitude earthquake struck Balochistan province in southern Pakistan, causing widespread destruction across several districts during more than 2 minutes of powerful tremors and shaking. Sadly at least 400 people were killed (some reports say 600) and over 100,000 have been left homeless. But a weirder — if much less tragic — effect of the quake that was soon reported worldwide was the sudden appearance of a new island off the coast, a mound of mud and bubbling methane seeps rising nearly 20 meters (70 feet) from the ocean surface.
The image above, taken by NASA’s Earth Observing-1 satellite, shows the newly-formed mud island a kilometer (0.6 miles) off the Gwadar coast.
According to an article by the Pakistani news site Dawn.com, the 250-by-100-foot-long pile of mud and rocks is leaking flammable gases.
“Our team found bubbles rising from the surface of the island which caught fire when a match was lit and we forbade our team to start any flame,” said Mohammad Danish, a marine biologist from Pakistan’s National Institute of Oceanography. “It is methane gas.”
Aerial photo of the Gwadar mud volcano (National Institute of Oceanography, Pakistan)
Pakistan’s many earthquakes are the result of collisions between the Indian, Arabian, and Eurasian tectonic plates. These sorts of mud volcanoes are not particularly unusual after large quakes there… it just so happened that this one occurred near a populated coast and in relatively shallow water. (Source)
(In fact two days later another mud island was spotted off the coast of the nearby coastal town of Ormara.)
The mud volcano, which is being called “Zalzala Jazeera” (earthquake island) is not expected to last long. Wave action will eventually sweep the sediment away over the course of several months. (Dawn.com.)
Artist rendering of Cygnus spacecraft approaching the International Space Station. Credit: Orbital Sciences Corp.
NASA and Orbital Sciences Corporation have announced a new date and time for the targeted arrival and berthing of the Cygnus spacecraft for its demonstration cargo resupply mission to the International Space Station. All the action will now take place on Sept. 29, a week later than originally planned, after a software glitch on the first rendezvous attempt, and a subsequent scheduling conflict due to the arrival of a Soyuz spacecraft with additional crew.
You can see the schedule of events below, as well as watch live on NASA TV’s UStream feed:
08:30 UTC (4:30 a.m. EDT: Cygnus rendezvous, grapple and berthing coverage begins on NASA Television.
11:15 UTC (7:15 a.m. EDT): Grapple of Cygnus by International Space Station’s Canadarm2 robotic arm
13:15 UTC (9:15 a.m. EDT): Cygnus berthing to Earth-facing port of Harmony node begins
17:00 UTC (1 p.m. EDT): Cygnus Post-Capture News Conference
ISS astronauts Karen Nyberg and Luca Parmitano are scheduled to grapple Cygnus with the station’s Canadian built robotic arm, working from the robotic work station in the Cupola module. They will install the cargo carrier at an Earth-facing docking port on the Harmony pressurized module.
Cygnus will deliver about 1,300 pounds (589 kilograms) of cargo, including student experiments, food and clothing, to the space station. Future Cygnus flights will ensure a robust national capability to deliver critical science research to orbit, significantly increasing NASA’s ability to conduct new science investigations to the only laboratory in microgravity.
Is it Friday already? Then it’s time for another Weekly Space Hangout. Join a team of dedicated space journalists to discuss the big space and astronomy news stories that broke this week. This time around, we discussed Amy Shira Teitel’s Buran article, ISON Watch 2013, and the re-re-discovery of water on Mars.
We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern, 2000 GMT. You can watch from here on Universe Today, or over on Google+ or YouTube.
Sandra Bullock as Ryan Stone in Warner Bros. Pictures' dramatic thriller "Gravity," a Warner Bros. Pictures release.
Image Credit: Courtesy of Warner Bros. Pictures
Actors for a new movie coming out in October 2013 received tips about life in space from NASA astronaut Cady Coleman. “Gravity” is the story of two astronauts (played by George Clooney and Sandra Bullock) whose shuttle is destroyed by a run-in with space junk during an EVA, stranding them both in orbit and struggling for survival.
While developing her role, Bullock gave Coleman a call while she was aboard the space station. At the time, the actress asked Coleman to elaborate on what it’s like living and moving about in microgravity. “I told her that I had long hair, and if you pulled a hair out and pushed it against something, you could move yourself across the space station,” said Coleman. “That’s how little force it takes.”
You can see more of their discussion below, as well as the heart-pounding trailer for the movie:
NASA says that although this dire scenario makes for gripping Hollywood entertainment, NASA actively works to protect its astronauts and vehicles from the dangers portrayed in the movie. From protective shielding and meticulous and methodical training on the ground and in space covering everything from spacewalking to fires or decompression inside the space station, NASA’s ground crews and astronauts are as prepared as they can be for potential anomaly, no matter how remote they may be.
Black holes are the most exotic and awe inspiring objects in the Universe.
Take the mass of an entire star. Compress it down into an object so compact that the force of gravity defies comprehension.
Nothing, not even light, can escape the pull of gravity from a black hole.
The idea was first conceived in the 18th century by the geologist John Mitchell. He realized that if you could compress the Sun down by several orders of magnitude, it would have gravity so strong that you’d need to be going faster than the speed of light to escape it.
Initially, black holes were considered nothing more than abstract mathematical concepts; even Einsten assumed they didn’t actually exist. But in 1931, the astronomer Chandrasekhar calculated that certain high mass stars might be able to collapse into black holes after all.
They turned out to be real, and over the next few decades, astronomers found many examples out in the Universe.
Stars are held in perfect balance by two opposing forces. There’s the inward pressure of gravity, attempting to collapse the star, counteracted by the outward pressure of the emitted radiation.
This artist’s concept illustrates a supermassive black hole with millions to billions times the mass of our sun. Supermassive black holes are enormously dense objects buried at the hearts of galaxies. Image credit: NASA/JPL-CaltechAt the core, millions of tonnes of hydrogen are being converted into helium every second, releasing gamma radiation. This fusion process is an exothermic reaction, meaning it releases more energy than it requires.
As the star consumes the last of its hydrogen, it switches to the stockpiles of helium that it has built up. After it runs out of helium, it switches to carbon, and then oxygen.
Since the star continues to pump out radiation, it balances out the gravitational forces trying to compress it.
Stars with the mass of our Sun pretty much stop there. Not massive enough to continue the fusion reaction, beyond oxygen, they become a white dwarf and cool down.
But for stars with about 5 times the mass of our Sun, the fusion process continues further up the periodic table to silicon, aluminum, potassium, and so on, all the way to iron.
No energy can be produced by fusing iron atoms together. It’s the stellar equivalent of ash.
And so, in a fraction of a second, the radiation from the star turns off. Without that outward pressure from the radiation, gravity wins out and the star implodes. An entire star’s mass collapses down into a smaller and smaller volume of space.
The velocity you would need to escape from the star goes up, until not even light is going fast enough to escape.
And this is how you form a black hole.
Well, that’s the main way.
You can also get black holes when dense objects, like neutron stars, collide with one another.
And then there are the supermassive black holes at the heart of every galaxy. And to be honest, astronomers still don’t know how those monsters formed.
This chart provides and accurate size comparison for every science fiction starship imaginable. Credit: Dirk Loechel. Click for original large version.
Have you always wanted to know how a Xurian Scout Fighter compares to a Valor-class Type-2 Valkyrie Attack Fighter? Wonder no more. DeviantARTist Dirk Loechel has created what is likely the most accurate and complete size comparison chart of almost every science fiction starship, from famous Star Trek and Stars Wars battle cruisers to ships from games like Halo to vessels from obscure sci-fi books. This new chart is an updated version of one Loechel made earlier. It looks like Loechel is taking suggestions for doing another update if you find he’s missed some.
Click on the image above to have access to the large original version on DeviantART, and enjoy the diversion.
