The hypernova of Eta Carinae is affecting our region of the galaxy
Eta Carinae is among the largest, most volatile stars in our galaxy. Its temperature is so high that it is unable to hold onto its own gas, with constant streams being ejected from the surface. It first came to attention in 1843 when it flared to magnitude -0.8, becoming the second brightest star in the night sky.
It subsequently died down, before brightening again in the late 1990s. This fluctuation continues – with periodic flaring and dimming – until one day the inevitable happens. Unable to maintain its cohesion, Eta Carinae erupts into one of the deadliest known forces in nature: a hypernova.
For a brief period, this colossal explosion outshines the entire galaxy. It is bright enough to be visible during daytime on Earth, while at night, it is similar to the full moon.*
Of much greater concern, however, are the lethal jets of gamma radiation released by the dying star. These begin to shoot outward, at such high energies that even systems thousands of light years away are affected. As a result, numerous planets in our region of the galaxy undergo mass extinctions during this time.*
Credit: NASA/GSFC/Dana Berry
Our Sun is exiting the Local Interstellar Cloud
The Local Interstellar Cloud (also known as the "Local Fluff") is a cloud of neutral hydrogen 30 light years across and flowing outwards from the Scorpius-Centaurus Association, a nearby star-forming region. The Solar System is thought to have entered the Local Interstellar Cloud sometime between 150,000 BC and 42,000 BC. Its density is about six times greater than the Local Bubble – a much larger region measuring 300 light years in diameter that surrounds both it and the G-Cloud, another cloud of gas.
In 2009, Voyager 2 data suggested that the magnetic strength of the local interstellar medium was much stronger than previously expected (3.7 to 5.5 μG, against previous estimates of 1.8 to 2.5 μG). The fact that the Local Interstellar Cloud is strongly magnetised was said to explain its continued existence, despite the pressures exerted upon it by the winds that blew out the Local Bubble. Its potential effects on Earth were prevented by the solar wind and the Sun's magnetic field.
By 12,000 AD, our Sun has exited the Local Interstellar Cloud and is heading towards the neighbouring G-Cloud, which contains the stars Alpha Centauri, Proxima Centauri and Altair.*
Click to enlarge
Betelgeuse is colliding with a dusty wall
Betelgeuse is the nearest red supergiant star to Earth. It can be seen with the naked eye in the northern hemisphere winter night sky as the orange-red star above and to the left of Orion's famous three-star belt. Roughly 1,000 times the diameter and 100,000 times the brightness of the Sun, Betelgeuse is on its way to becoming a supernova, having already swelled in size and shed a significant fraction of its outer layers.
The star's winds are crashing against the surrounding interstellar medium, producing a curved "bow shock" as the star moves through space at 30 km/s. A series of broken, dusty arcs ahead of the star's direction of motion testify to a turbulent history of mass loss.
In the early 21st century, the Herschel Space Observatory found a mysterious wall-like structure in far-infrared. It was seen further away from the star, beyond the dusty arcs, its linear shape indicating that it was completely separate from and unrelated to Betelgeuse. It was, however, being illuminated by the supergiant. Astronomers of the time believed it was either a linear filament linked to the Galaxy's magnetic field, or the edge of a nearby interstellar cloud.
In 7000 AD, a collision occurs between the wall and the bow shock zone. This is followed by a collision between the wall and Betelgeuse itself, some 12,500 years later.*
Credit: ESA/Herschel/PACS/L. Decin et al
The Chernobyl disaster site becomes fully safe
The Chernobyl explosion, which occurred in 1986, was the worst nuclear accident in history – affecting tens of thousands of square kilometres of land. Radiation at the centre of the former disaster zone has decayed to negligible levels by now.*
Chernobyl radiation hotspots. Credit: CIA
The first wave of sub-light vessels has reached the galactic core
The core region is located 27-28,000 light years from Earth. At its centre lies the largest black hole in the galaxy – a supermassive black hole.* Having travelled for many millennia, the first wave of sub-light spacecraft has now arrived in its vicinity.
These ships contain no physical human crew, being entirely computerised and automated. Numbering in the trillions, they have self-replicated along the way, using local stellar and planetary material gathered en route.* Systems encountered during this epic voyage have become seeded with computational substrates and saturated with artificial intelligence – individual planets and moons becoming like brain cells in a gigantic, artificial organism. It is almost as though the galaxy itself is waking up and achieving self-awareness.*
There is no competition or battle to claim ownership of the core. Wars, greed and archaic concepts of nationality have long since disappeared, with sentient beings now united under a common heritage.
In addition to the black hole, there are dense concentrations of ancient, metal-rich stars; in places separated by only a few light weeks or light days. These provide an enormous pool of resources for the approaching fleets.
Gamma radiation is so high in this region that almost nothing biological can survive, except for the hardiest of extremophile bacteria. Were an observer able to stand on a planet near the core, the sky above them would appear as a dazzling display of light and colour.
Having reached the galactic centre, efforts are now underway to explore the far side of the galaxy and the mysteries that lie beyond. Dozens of globular clusters have also been reached by now.*
Credit: NASA, ESA and A. Schaller (for STScI)
Ross 248 becomes the closest star to our Sun
Alpha Centauri was previously the closest star. Ross 248 is a red dwarf, with approximately 12% of the Sun's mass and 16% of the Sun's radius, but only 0.2% of its luminosity. However – it is also a "flare star", that periodically undergoes sudden, dramatic increases in brightness for a few minutes.
In 2010, Ross 248 was 10.3 light years from Earth, with a radial velocity of -81 km/s. By 35,000 AD, it is closer than Alpha Centauri. It reaches its closest point in 38,000 AD – moving to within 3.1 light years – before receding again, becoming further from the Sun than Alpha Centauri in 44,000 AD.
Voyager 1 is passing near the red dwarf star, Gliese 445
Launched by NASA in 1977, the Voyager I space probe continues to drift through interstellar space. It is now passing near Gliese 445, an M-type main sequence star in the constellation of Camelopardalis, close to Polaris.* Its sister probe, Voyager 2, will reach Sirius in approximately 298,000 AD.
Tetrafluoromethane emissions from 2000 AD have been naturally reabsorbed
Tetrafluoromethane, also known as carbon tetrafluoride (CF4) is the longest-lived of all the greenhouse gases. Like other fluorocarbons, CF4 is very stable due to the strength of its carbon–fluorine bonds. Although structurally similar to chlorofluorocarbons (CFCs), it does not deplete the ozone layer. However, its heat-trapping potential is extremely high – roughly 11,200 times that of CO2 when measured on a per-molecule basis over a 500-year timescale.* Circa 2000 AD, the atmospheric concentration of CF4 was 80 parts per trillion. The main applications were as a low temperature refrigerant, in electronics microfabrication, as a plasma etchant (in combination with oxygen) and in neutron detectors.
The KEO time capsule re-enters Earth's atmosphere*
KEO was a time capsule launched in 2015 and intended to orbit Earth for 50,000 years – the same length of time that had elapsed since early humans began drawing in cave walls. The project was supported by the UN Educational, Scientific and Cultural Organization (UNESCO) as well as the European Space Agency (ESA) and other institutions.
The public were invited to contribute messages.* These were encoded in glass-made, radiation-resistant DVDs, along with instructions to future generations on how to build a DVD reader. Samples of human blood, earth, air and seawater were also placed on board.
The capsule itself is a hollow sphere, 80cm in diameter. The sphere is engraved with a map of Earth and surrounded by an aluminium layer, a thermal layer and several layers of titanium, intertwined with vacuum. The sphere is resistant to cosmic radiation, atmospheric re-entry and space junk impacts.
Placed into orbit 1,800 km high, the satellite's altitude has slowly degraded by a few dozen metres each year. As it finally re-enters the atmosphere, its thermal layer produces a bright, artificial aurora to signal its return.
The red hypergiant star, VY Canis Majoris, has exploded by now, producing one of the largest supernovas the galaxy has ever seen*
VY Canis Majoris, at between 1800 and 2100 times bigger than our Sun (8.4–9.8 au, 2.7 billion km or 1.7 billion miles in radius), is the largest known star in the Milky Way, and also one of the brightest known. It is located around 4,900 light years from Earth, in the constellation Canis Major. It was discovered to be very unstable, throwing off much of its mass into the surrounding nebula. By 100,000 it has finally exploded, creating a supernova bright enough to be seen during daylight hours on Earth.
Constellations visible from Earth have been rendered unrecognisable
Proper motion – the continuous movement of celestial bodies due to changing orbits or the remaining effects of the Big Bang – has radically changed the view of the night sky from Earth. Stars naturally move at different velocities, depending on the manner in which a star formed from its original dust cloud. By 50,000 AD, constellations were beginning to be twisted and bent into new shapes* and by 200,000 AD have become completely unrecognisable.* This includes once famous groups of stars like the Big Dipper, Orion, Ursa Major, Perseus and Gemini. As a result of changes in Earth's axial orientation, Gamma Cephei, Iota Cephei and Vega have taken the position of the North Star.
Voyager 2 is approaching Sirius
Voyager 2 was an unmanned space probe launched in 1977 to investigate the outer planets of the solar system. Identical in form and function with its sister craft, Voyager 1, it was launched on a slower, more curved trajectory that allowed it to be kept in the plane of the ecliptic. This enabled it to be sent on to Uranus and Neptune by means of utilising gravity assists during its fly-by of Saturn in 1981 and of Uranus in 1986.
By 2010, Voyager 2 was around 92 AU (13.75 billion km, 8.5 billion miles, or 0.001443 ly) from the Sun, deep in the scattered disc, and traveling outward at roughly 3.26 AU per year.
The probe survives for thousands of years in the emptiness of interstellar space. It eventually passes by Sirius, having covered a distance of over 25 trillion miles.* Sirius is the brightest star in the sky when viewed from Earth.
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1 Eta Carinae, Wikipedia.org:
Accessed 14th November 2009.
2 It is unlikely that Earth would be affected. Even if the gamma ray jets point in our direction, the solar system will likely be protected by a Dyson shell (or similar giant structure) by then. Less developed colonies in other star systems might not be so fortunate, however.
3 "Our Sun may exit the Local Cloud, also called the Local Fluff, during the next 10,000 years."
See Astronomy Picture of the Day, NASA:
Accessed 19th January 2014.
4 "...the outermost arc will collide with the bar in just 5000 years, with the red supergiant star itself hitting the bar roughly 12,500 years later."
See Betelgeuse Braces for a Collision: Red Supergiant Star to Crash Into Dusty 'Wall', Science Daily:
Accessed 24th January 2013.
5 "There is a 17 mile Exclusion Zone around Chernobyl where officially nobody is allowed to live, but people do. These "resettlers" are elderly people who lived in the region prior to the disaster. Today there are approximately 10,000 people between the ages of 60 and 90 living within the Zone around Chernobyl. Younger families are allowed to visit, but only for brief periods of time.
"Eventually the land could be utilized for some sort of industrial purpose that would involve concrete sites. But estimates range from 60–200 years before this would be allowed. Farming or any other type of agricultural industry would be dangerous and completely inappropriate for at least 200 years. It will be at least two centuries before there is any chance the situation can change within the 1.5-mile Exclusion Zone. As for the #4 reactor where the meltdown occurred, we estimate it will be 20,000 years before the real estate is fully safe."
Wasted Lives, Valuable Lessons, Randall Bell
Accessed 30th July 2010.
6 Galactic Center, Wikipedia:
Accessed 12th February 2011.
7 von Neumann Probe, daviddarling.info:
Accessed 12th February 2011.
8 "We will ultimately saturate all of the matter and energy in our
area of the universe with our intelligence... All of this dumb matter
and energy around us will wake up and become sublimely intelligent. Then
it will spread out to the whole universe at the fastest speed information
can flow. And one could make an argument that it’s not going to
take an infinitely long time because there may be other ways to get to
other parts of the universe through shortcuts like wormholes, which physics
has postulated. Eventually the whole universe will, essentially, wake
The technology of universal intelligence, KurzweilAI:
Accessed 12th February 2011.
9 Globular Clusters, Atlas of the Universe:
Accessed 12th February 2011.
10 Voyager Humanity's Farthest Journey, SpaceRip:
Accessed 3rd May 2011.
11 Greenhouse Gas – Global Warming Potential, Wikipedia:
Accessed 28th August 2014.
12 FAQ, KEO:
Accessed 29th October 2010.
13 Your message, KEO:
Accessed 29th October 2010.
14 Crazy Image Shows How Tiny Earth Is Compared To Our Sun, Business Insider:
Accessed 29th December 2017.
15 What Will the Constellations Look Like in 50,000 Years?, Discovery News:
Accessed 1st August 2012.
17 Voyager – Interstellar Mission, Nasa.gov:
Accessed 25th May 2009.