Monday, September 19, 2016

The Sun will destroy Earth sooner than you might think

Kevin Gill
There are plenty of ways Earth could go. It could smash into another planet, be swallowed by a black hole, or get pummelled to death by asteroids. There’s really no way to tell which doomsday scenario will be the cause of our planet’s demise.

But one thing is for sure - even if Earth spends the rest of its eons escaping alien attacks, dodging space rocks, and avoiding a nuclear apocalypse, there will come a day when our own Sun will eventually destroy us.

This process won’t be pretty, as Business Insider’s video team recently illustrated when they took a look at what will happen to Earth when the Sun finally does die out in a blaze of glory.
And as Jillian Scudder, an astrophysicist at the University of Sussex, explained to Business Insider in an email, the day might come sooner than we think.

Bleeding Earth dry

The Sun survives by burning hydrogen atoms into helium atoms in its core. In fact, it burns through 600 million tons of hydrogen every second.

And as the Sun’s core becomes saturated with this helium, it shrinks, causing nuclear fusion reactions to speed up - which means that the Sun spits out more energy.

In fact, for every billion years the Sun spends burning hydrogen, it gets about 10 percent brighter.

And while 10 percent might not seem a lot, that difference could be catastrophic for our planet. 

"The predictions for what exactly will happen to Earth as the Sun brightens over the next billion years are pretty uncertain," Scudder said.

"But the general gist is that the increasing heat from the Sun will cause more water to evaporate off the surface, and be held in the atmosphere instead. The water then acts as a greenhouse gas, which traps more incoming heat, which speeds up the evaporation."

Before it ever even runs out of hydrogen, the Sun’s high energy light will bombard our atmosphere and "split apart the molecules and allow the water to escape as hydrogen and oxygen, eventually bleeding Earth dry of water", Scudder said.

ESO/L. Calçada
 And it doesn’t end there. 

A 10 percent increase in brightness every billion years means that 3.5 billion years from today, the Sun will shine almost 40 percent brighter, which will boil Earth’s oceans, melt its ice caps, and strip all of the moisture from its atmosphere.

Our planet, once bursting with life, will become unbearably hot, dry, and barren - like Venus.

And as the steady thump of time drums down on our existence, the situation will only get more bleak.

The Sun’s death rattle

All good things eventually come to an end. Every book has a final chapter, every pizza has one last bite, and every person has a dying breath.

And one day, about 4 or 5 billion years from now, the Sun will burn through its last gasp of hydrogen and start burning helium instead.

"Once hydrogen has stopped burning in the core of the Sun, the star has formally left the main sequence and can be considered a red giant," Scudder said.

"It will then spend about a billion years expanding and burning helium in its core, with a shell around it where hydrogen is still able to fuse into helium."

Kevin Gill
As the Sun sheds its outer layers, its mass will decrease, loosening its gravitational hold on all of the planets. So all of the planets orbiting the Sun will drift a little further away.

When the Sun becomes a full blown red giant, Scudder said, its core will get extremely hot and dense while its outer layer expands ... a lot.

Its atmosphere will stretch out to Mars’ current orbit, swallowing Mercury and Venus.

Although the Sun’s atmosphere will reach Mars’ orbit, Mars will escape, as it will have wandered past the reach of the Sun’s expanding atmosphere.

Earth, on the other hand, has two options: either escape the expanding Sun or be consumed by it. But even if our planet slips out of the Sun’s reach, the intense temperatures will burn it to a sad, dead crisp.

"In either case, our planet will be pretty close to the surface of the red giant, which is not good for life," Scudder said.

Although more massive stars can begin another shell of fusing heavier elements when this helium is exhausted, the Sun is too feeble to generate the pressure needed to begin that layer of fusion, Scudder explained.
So when the Sun’s helium dries up, it’s pretty much all downhill from there.

From red giant to white dwarf

Once the Sun has emptied its fuel reserves, it will become unstable and start to pulse. With every pulse, the Sun will shrug off layers of its outer atmosphere until all that’s left is a cold, heavy core, surrounded by a planetary nebula.


X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI

 With each passing day this core, known as a white dwarf, will cool and fade hopelessly out of existence as if it didn’t once host the most lively planet ever discovered in the sweeping canvas of the Universe.

But who knows. Maybe the aliens will get to us first.

The most inspirational thing about a future Mars colony is you

We’re knocking on the door of humanity’s next great project.
HUMAN colonisation of Mars could occur in under two decades and the man largely responsible for making it happen is inspired by the amount of people putting their hands up for the mission. 
Jason Crusan has a pretty tough job, but it may not be as tough as those willing to lead the human settlement on the Red Planet and usher in a new age of galactic colonisation.

Mr Crusan is the former chief technologist for space operations for NASA, and in 2012 became the director of the Advanced Exploration Systems Division within the Human Exploration and Operations Mission Directorate at the world’s leading space agency.

It sounds like a mouthful but according to NASA, simply put he develops the innovative approaches needed to maximise the agency’s access to new technologies and capabilities for human spaceflight.

It’s a role that would inspire little boys and girls all over the world to study space science, but he says there’s plenty of ways to contribute to humanity’s next big project.

“We’re going to need people to learn how to operate machinery and live off the land ... Mars has a very harsh environment so we’re gonna need people to maintain machines and operate those machines and be able to produce oxygen and the water we’ll need,” he told news.com.au. “A lot of those infrastructure activities are going to be critical to any kind of permanent settlement.”

After the first few missions of astronauts, it’s expected a lucky (and arguably somewhat deranged) group of people will head to the planet in a bid to establish the first liveable base for human settlement. Already seven Australians are among the candidates picked to take the historic one way trip to outer space.




Martha Lenio collects a soil sample outside of the dome in which six scientists lived an isolated existence to simulate life on a mission to Mars, on the bleak slopes of dormant volcano Mauna Loa near Hilo on the Big Island of Hawaii. Picture: Neil Scheibelhut/APSource:Supplied

The trip to Mars takes a year and the first missions towards that goal of deploying human cargo are set to take place in the 2020s and will involve a number of flights in and around the Moon.

He expects by the 2030s NASA will have well and truly begun building the systems to enable us to land on Mars and begin the learning process.

“If you stay much longer than a couple weeks, you actually have to stay for an entire year in order for the alignment between Earth and Mars to line back up so you can actually come back home in a reasonable amount of time,” he said.

When we do get there, the planet’s moons could play a crucial role in managing our presence.

“The moons of Mars are very interesting as well, they likely have a lot of water on them, they have material that we could use. They’re location and their size allow them to serve as radiation shields,” he said.

“You could dock up to a moon of Mars and actually shield yourself from a majority of the radiation environment of deep space and then explore ... and use that as kind of a staging point to then go to the surface.”

If Matt Damon can do it, so can the rest of us.Source:YouTube


Mr Crusan will be in Australia for upcoming event featuring Buzz Aldrin who is vigorously pushing for the global community to better focus its efforts on achieving the mission of putting humans on Mars.

He has previously said the world is not doing enough and complained that governments have lost their appetite for space exploration since the Apollo missions. To some extent, Mr Crusan agrees.

“The simple answer is that we could always do more,” he said. “As more countries join and more countries contribute, the pace at which the mission could be done absolutely could be increased,” he said.

Compared to the Apollo missions, the expedition to Mars “is orders of magnitude harder and “the magnitude of the risk is a lot higher.”

However while it’s unquestionably an extremely tough endeavour “it’s one that’s worthy of all the countries’ contribution,” he said.

Tickets are on sale now for National Geographic’s MARS: The Live Experience in Melbourne (Nov 4), Sydney (Nov 6), and Canberra (Nov 7). Visit ticketek.com.au/mars



Buzz Aldrin will be touring the country in early November.Source:Supplied

NASA’s Mars 2020 Rover to Produce Oxygen on the Red Planet



NASA’s Mars 2020 rover will not only investigate the Red Planet, searching for evidence of past life on Mars, but it also expected to lay foundations for future human exploration of the planet. One of the mission’s instrument called MOXIE will have a special task, testing technology essential for Mars colonization.
“MOXIE is one of nine instruments but it is the only one that is relevant to human exploration,” Donald Rapp, one of the co-investigators of MOXIE, told Astrowatch.net.
MOXIE stands for the Mars Oxygen In-Situ Resource Utilization Experiment. With a diameter of 9.4 x 9.4 x 12.2 inches (23.9 x 23.9 x 30.9 centimeters), the instrument will produce oxygen from the Martian carbon-dioxide atmosphere at a rate of about 0.022 lbs. (10 grams) per hour. It is a 1:100 scale test model of a future instrument that would be efficient for human explorers on Mars.
“The object is not to produce a lot of oxygen. The object is to show that the process works on Mars. MOXIE produces only about 10 per hour of oxygen, less than one percent of full scale,” Rapp said.
Martian atmosphere is 96 percent carbon dioxide and MOXIE will work just like a tree - inhaling carbon dioxide and exhaling oxygen. It will collect carbon dioxide from the atmosphere, compress and store it, then it will electrochemically split the carbon dioxide molecules into dioxygen and carbon monoxide. The dioxygen will be then analyzed for purity before being vented back out to the Mars atmosphere along with the carbon monoxide and other exhaust products.
MOXIE will consume up to 300 W of power and will operate at 800 degrees Celsius, requiring a sophisticated thermal isolation system, including input gas preheating and exhaust gas cooling. The instrument’s design includes technology to investigate dioxygen exhaust and carbon dioxide/carbon monoxide exhaust streams, that will be analyzed to verify the oxygen production rate and purity.
Mars Oxygen ISRU Experiment (MOXIE) is an exploration technology investigation that will produce oxygen from Martian atmospheric carbon dioxide. Image Credit: NASA

However, if MOXIE successfully completes its task, a future full-scale instrument will need to consume more resources to work properly.
“If MOXIE works well, scale-up is feasible. However, scaled up version will require considerable power,” Rapp noted.
A full-scale MOXIE-like instrument could be employed to produce oxygen on a larger scale, mainly for life-sustaining activities for humans. The system could also deliver liquid oxygen needed to burn rocket fuel for a return trip to Earth. Moreover, the carbon monoxide that will be also produced by the instrument may be utilized directly as fuel or converted to methane for use as propellant.
Meanwhile, MOXIE is in its early stages of development. The instrument has recently passed the Preliminary Design Review.
“The instrument passed Preliminary Design Review favorably and is scheduled for Critical Design Review in about six months. After that, we proceed to build and test the flight model,” Rapp revealed.
Mars 2020 mission is expected to deliver important information about the potential habitability of the Red Planet. Besides testing method for producing oxygen from the atmosphere, the rover is designed to identify other resources such as water, improve landing techniques, and characterize weather, dust, and other potential environmental conditions that could affect future astronauts on Mars.
The mission, managed by NASA's Jet Propulsion Laboratory in Pasadena, California, is currently slated to be launched in July 2020, atop an Atlas V booster, from Cape Canaveral Air Force Station in Florida.

Sunday, September 18, 2016

The 19 Craziest Hubble Pictures of All Time

The Hubble Space Telescope has continuously unleashed a stream of jaw-dropping intergalactic imagery since it launched on April 24, 1990. Not only do these images, which look more like paintings at first glance, allow researchers to study distant worlds, galaxies and nebulae, they have captured the minds of the general public, getting us genuinely excited about space exploration. But here's some sad news: despite all of these wonderful things, Hubble is getting older.

In a few short years, Hubble's technology will become fully outdated and NASA will let it drift to a fiery death in the atmosphere, like some crazed band of space Vikings. Once gone, at least we know we'll have the gold-encrusted James Webb Space Telescope to keep the images flowing in. With time marching on, let's not worry about what will happen to everyone's favorite space telescope and, instead, take a look at some of the most amazing pictures it's given us over the years.

1. A Rose Made Of Galaxies
Released on Hubble's 21st anniversary, a pair of galaxies swirl together to form Arp 273. This unique object formed as two galaxies in the Andromeda constellation passed through one another.

2. When Black Holes Collide

Though there isn't an actual picture of a supermassive black hole (yet), this image possibly captures two of them swirling together and shooting off jets of particles into the universe. Each of these jets, which travel at nearly the speed of light, stretch for thousands of light-years as two galactic nuclei blend together.

3. The Pillars Of Creation
Taken in 1995, the 'Pillars of Creation' is one of Hubble's most notable images. Inside, you see three cold columns of gas illuminated by stars in the Eagle Nebula. This re-released version of the original adds more detail by including near-infrared light, which helps expose the various stars behind the pillars. Few other space images have received as much fame and adoration as this one.
4. A Churning View Of Sagittarius
The Lagoon Nebula churns with a series of crazy, huge storms. "The region is filled with intense winds from hot stars, churning funnels of gas, and energetic star formation, all embedded within an intricate haze of gas and pitch-dark dust," NASA notes. This colorful image was released in August 2015.


5. A Supernova Impostor
Meet the Eta Carinae system. It has two stars in it and one of them is huge and unstable. Since the 1800s, astronomers with less powerful telescopes have been watching the system's outbursts. However, it wasn't until Hubble came that researchers were able to fully check out the clouds of matter, dubbed the Homunculus Nebula, thrown off by it. This image in particular, which was released in 2012, is one of the most detailed. Researchers refer to these sort of outbursts as 'impostor supernovae' because they appear like normal supernovae but they do not kill off the star.
6. The Bubble Galaxy
Known scientifically as NGC 3521, this flocculent spiral galaxy appears woolly because of how stars shine through its dusty clouds. Though it seems incredibly close in this image, it actually lies about 40 million light-years away in the constellation of Leo, and it was discovered back in 1784 by William Herschel. Hubble released this incredibly detailed picture back in 2015, though if you were to look at it with an ordinary backyard telescope it would appear like a giant bubble.


7. Di Cha Shines Through A Smoke Ring
The star system DI Cha was imaged by Hubble in October 2015. The unique bright spot in its center consists of two stars shining through rings of dust, which actually hide two other stars in this quadruple star system. Besides having two pairs of binary stars, the system is notable because it has a large region known as the Chamaeleon Complex, an area that gives birth to brand new stars.

8. Fingerprinting The Stars
Front and center in this March 2016 Hubble image is a star named IRAS 12196-6300, which lies 2,300 light-years from Earth. Researchers call this type of image a fingerprint because the light spreads out enough for them to understand what chemicals make up the star.
9. Celestial Fireworks
There is just so much going on in this image that it's hard to pin down just one thing to discuss. Inside, we see a ton of young stars inside a nebula. "The nebula reveals a fantasy landscape of pillars, ridges and valleys," says a NASA statement. "The pillars, composed of dense gas and thought to be incubators for new stars, are a few light-years tall and point to the central star cluster. Other dense regions surround the pillars, including reddish-brown filaments of gas and dust."



10. Pismis 24 
A Fantastical Triple Star System
While this may look the cover a direct-to-VHS fantasy film from the late-80s, this Hubble image showcases the open cluster known as Pismis 24, the three stars directly above the nebula. In fact, the biggest star of the three, Pismis 24-1, is one of the largest stars ever recorded at 100 solar masses.

11. A Galaxy Full of Dark Matter
Reminiscent of the default Mac background, this image shows off the galaxy UGC 447, which lies 110 million light-years away in the constellation of Pisces. Researchers believe galaxies like UGC 447 are composed mainly of dark matter, making them prime targets for future study because, though researchers see evidence of it everywhere, dark matter is super elusive. This is one of the relatively recent images captured by Hubble in April 2016.


12. The Monkey Head Nebula Births Stars

To celebrate Hubble's 24th anniversary (they always put out great images for anniversaries), researchers released this image of the Monkey Head Nebula, which is basically a star factory. This region specifically lies about 6,400 light-years from Earth.
  
13. Two spiral galaxies in the process of merging.
NGC 2207 and IC 2163 Located about 130 million light years from Earth, in the constellation of Canis Major, this pair of spiral galaxies has been caught in a grazing encounter. NGC 2207 and IC 2163 have hosted three supernova explosions in the past 15 years and have produced one of the most bountiful collections of super bright
14. An expanding supernova remnant 
W44 Also known as G34.7-0.4, W44 is an expanding supernova remnant that is interacting with dense interstellar material that surrounds it. X-rays from Chandra (blue) show that hot gas fills the shell of the supernova remnant as it moves outward. Infrared observations from the Spitzer Space Telescope reveal the shell of the supernova remnant (green) as well as the molecular cloud (red) into which the supernova remnant is moving and the stars in the field of view in Constellation Aquila
15. The Ibex Nebula
An intriguing and beautiful nebula, NGC 3576 drifts through the Sagittarius arm of our spiral Milky Way Galaxy. Within the region, episodes of star formation are thought to contribute to the complex and suggestive shapes. NGC 3576 itself is about 100 light-years across and 9,000 light-years away in the southern constellation of Carina, not far on the sky from the famous Eta Carinae Nebula. Near the left edge of the picture is NGC 3603, a much larger but more distant star forming region. 
16. Boomerang Nebula
This reflecting cloud of dust and gas has two nearly symmetric lobes (or cones) of matter that are being ejected from a central star. Over the last 1,500 years, nearly one and a half times the mass of our Sun is about 5,000 light-years from Earth in the direction of the Southern constellation Centaurus. 
17. Cat's Eye Nebula
Constellation: Draco
Distance: 3,000 light-years
Though the Cat’s Eye Nebula was one of the first planetary nebulae to be discovered, it is one of the most complex such nebulae ever seen. Planetary nebulae form when Sun-like stars gently eject their outer gaseous layers, creating amazing and confounding shapes. The Cat’s Eye Nebula, also known as NGC 6543, is a visual “fossil record” of the dynamics and late evolution of a dying star. It is estimated to be 1,000 years old.
18. The Hand of God
A small, dense object only 12 miles in diameter is responsible for this beautiful X-ray nebula that spans 150 light years. The hand might look like an X-ray from the doctor's office, but it is actually a cloud of material ejected from a star that exploded. 
19. The Double Ring Galaxies of Arp 147
How could a galaxy become shaped like a ring? Even more strange: how could two? The rim of the blue galaxy pictured on the right shows an immense ring-like structure 30,000 light years in diameter composed of newly formed, extremely bright, massive stars. This blue galaxy is part of the interacting galaxy system known as Arp 147,
and shows a ring because it has recently collided with the other galaxy in the frame, the red galaxy on the left.
20. 'Enterprise' Nebulae 
These nebulae seen by NASA's Spitzer Space Telescope, at left, may resemble two versions of the starship Enterprise from "Star Trek," overlaid at right.
the region pictured in the image falls within the disk of our Milky Way galaxy and displays two regions of star formation hidden behind a haze of dust when viewed in visible light. Spitzer's ability to peer deeper into dust clouds has revealed a myriad of stellar birthplaces. however, may prefer using the more familiar designations NCC-1701 and NCC-1701-D. Fifty years after its inception,
    

Saturday, September 17, 2016

Origin of minor planets’ rings revealed

Figure 1: (left) Visualization of Chariklo and its rings, provided by the European Southern Observatory (http://www.eso.org/public/images/eso1410b/). Credit: ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org).
(right) Visualization of the rings as seen from Chariklo’s surface, provided by the European Southern Observatory (https://www.eso.org/public/images/eso1410a/) Credit: ESO/L. Calçada/Nick Risinger (skysurvey.org).
A team of researchers has clarified the origin of the rings recently discovered around two minor planets known as centaurs, and their results suggest the existence of rings around other centaurs. These findings were published on August 29 in Astrophysical Journal Letters, and introduced in AAS Nova, a website for research highlights from the journals of the American Astronomical Society. 


The lead author of the paper is HYODO Ryuki (Kobe University Department of Planetology, Graduate School of Science), and co-authors are Professor Sébastien Charnoz (Institute de Physique du Globe/Université Paris Diderot), Project Associate Professor GENDA Hidenori (Earth-Life Science Institute, Tokyo Institute of Technology), and Professor OHTSUKI Keiji (Kobe University Department of Planetology, Graduate School of Science).


Centaurs are minor planets that orbit between Jupiter and Neptune, their current or past orbits crossing those of the giant planets. It is estimated that there are around 44,000 centaurs with diameters larger than one kilometer.

Until recently it was thought that the four giants such as Saturn and Jupiter were the only ringed celestial bodies within our solar system. However, in 2014 observations of stellar occultation (an event that occurs when light from a star is blocked from the observer by a celestial body) by multiple telescopes revealed that rings exist around the centaur Chariklo (see Figure 1). Soon after this, scientists discovered that rings likely exist around another centaur, Chiron, but the origin of the rings around these minor planets remained a mystery.


The team began by estimating the probability that these centaurs passed close enough to the giant planets to be destroyed by their tidal pull. Their results showed that approximately 10% of centaurs would experience that level of close encounter. Next, they used computer simulations to investigate the disruption caused by tidal pull when the centaurs passed close by the giant planets. The outcome of such encounters was found to vary depending on parameters such as the initial spin of the passing centaur, the size of its core, and the distance of its closest approach to a giant planet (Figure 2). They found that if the passing centaur is differentiated and has a silicate core covered by an icy mantle, fragments of the partially-destroyed centaur will often spread out around the largest remnant body in a disc shape, from which rings are expected to form.

The results of their simulations suggest that the existence of rings around centaurs would be much more common than previously thought. It is highly likely that other centaurs with rings and/or small moons exist, awaiting discovery by future observations. 

Figure 2: Examples of snapshots of simulations with different initial conditions. The center of each panel shows a centaur after being partially destroyed, and the fragments around it distributed in a disc shape, from which observed rings are expected to form (from Hyodo et al. 2016, Astrophysical Journal Letter 828, L8)

Technical terms
1. Centaur:
small celestial bodies that orbit between Jupiter and Neptune. Their current or past orbits repeatedly cross those of the giant planets, and sometimes pass very close by the giant planets themselves.
2. Chariklo:
a centaur with a radius of approximately 250 kilometres. In 2014 it was clarified by stellar occultations that this centaur has rings.
3. Chiron:
a centaur with a radius of approximately 220 kilometres. Like Chariklo, it is thought to possess rings based on data from multiple observations.
Journal
Astrophysical Journal Letters

Saturn’s rings may be from the whirl of a passing icy rock


Origin of rings is elusive

NASA/JPL/Space Science Institute
Put a spin on it. Saturn’s rings might have formed when it ate a rotating icy rock that passed too close. This scenario could explain why Saturn’s rings are made of different stuff from those of other gas giants.
Existing theories assume that rings form when objects such as asteroids or comets are pulverised by the gravity of a planet like Saturn. But they fail to explain why Saturn’s rings are mostly water ice, while other gas giants’ are rocky, says Ryuki Hyodo at Kobe University in Japan.
“The origin of Saturn’s rings remains elusive,” he says.
Earlier models estimated how much mass a planet might capture from a passing celestial object based on physical properties such as the size of the planet and the smaller body, and the distance between the two.
But Hyodo and his colleagues also considered the way the passing object whirls through space: whether its tumbling lines up with the direction in which it travels around the planet, or if it is doing backflips.
That distinction is important, the team found. Passing bodies that rotate in the same direction as their path around the planet are more easily broken up, and their fragments more efficiently sucked into orbit.
That is because the planet’s gravity pulls harder on the closer side of the small object, tugging it around in the same direction as it is travelling. If the planet’s gravity has to work against the object’s spin, it will be unable to sweep in as much material as when they are aligned.

Shape-shifting spheres

Those uneven gravitational forces could pull and deform a passing object like a piece of taffy.

To see what Saturn and Uranus might do to passing objects spinning in different ways, the team simulated how individual bits of a round object move based on properties such as mass and density. They modelled more complex bodies than have been tried before: rather than just a homogeneous ball, they included more realistic objects with a hard, rocky core surrounded by an icy mantle.

In some Saturn scenarios, only the outer layer of frozen water was swept up by the planet, creating proto-rings that could have evolved into the icy bands visible today.

The Uranus simulations, however, tended to produce rockier rings. Because Uranus is denser than Saturn, it can seize more of the deeper, rockier part of a passing body than Saturn before the fragments collide with the planet instead of forming rings.

Pristine rings

The study is a step forward, says Matthew Tiscareno at the SETI Institute in Mountain View, California, but a question of timing remains.

Saturn and the other giant planets would have been most likely to encounter passing bodies like the ones Hyodo and his team simulated about 4000 million years ago, Tiscareno says. Since then, most of those objects have smashed into planets or been ejected from the solar system.

But the clean water ice of Saturn’s ring system suggests that it may be much younger, since interplanetary dust should pollute it over time.

“Even if you can get it in the first place, how does it survive for 4 billion years and still look pristine?” Tiscareno asks.

Journal reference: arXiv, DOI: arXiv:1609.02396v1

Size Comparisons of the Largest Objects in the Known Universe

Scale representation of comet 67P compared to LA by Matt Wang

Here’s How Big Our Cities Really Are.

Los Angeles seems like a relatively big town. In fact, it is the second largest city in the United States. The area spans 502 square miles (1,300 sq km), and some 4 million people calling this place “home.” However, L.A. is dwarfed by even the smallest objects in our solar system. Recently, for the first time ever, humanity landed a probe on a comet. The comet is known as 67P/Churyumov-Gerasimenko (or 67P, for short). The journey to this icy body took nearly a decade. Here, Matt Wang compares the size of the comet to downtown Los Angeles. As you can see L.A. is rather smallish by comparison.


This is home.

To the everyday individual, our planet probably seems like a rather large place. At the equator, the circumference of Earth is 24,902 miles (40,075 km). And ultimately, this Pale Blue Dot houses all the known life in the universe. That’s 8.7 million species (give or take a few million) and some 7 billion people.

NASA Image of Earth via Wikimedia Commons

This is How Big Our Planet Really is.

This is Jupiter’s Great Red Spot. It is a massive storm system that has existed for hundreds of years. Ultimately, it is 12,400 miles long and 7,500 miles wide (20,000 km by 12,000 km). So saying that you’ll be blown away by this storm is an understatement of epic proportions. Our entire planet would be blown away. Even at its smallest, this storm could easily swallow two to three Earths. 1,300 Earths could fit inside the planet itself.

Jupiter’s Great Red Spot compared to Earth. Image Credit: Michael Carroll

Here’s Our Planet Compared to Our Star.

Solar Flares are marvelous (and utterly terrifying) solar events. Generally referred to as “solar storms,” these phenomena can release energy that is equivalent to over a million 100-megaton hydrogen bombs. If you look at the image above, you’ll get a pretty good idea of what this means. Here, we see a NASA rendition of Earth compared to a solar flare. Fortunately, as the material is ejected from the Sun, it is dispersed across the solar system by stellar winds (so we don’t get anywhere near a direct blast).

Earth compared to the Sun. Image credit: NASA

This is our Sun’s Sphere of Influence.

Our Sun is amazingly powerful. In fact, it is so powerful, it is able to influence objects that are literally light-years away. To break this down a bit, the Earth is just about 152 million km from the Sun (about 96 million mi). The Oort cloud is one of the most distant structures that our star dominates, and it is a staggering  4.6 trillion miles (7.4 trillion km) from the Sun. If that’s not enough, it is believed to extend much, much farther than this into space, ultimately make it light-years from the Sun. This portion of our neighborhood is nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun (which gives you some idea of just how far the Sun’s influence extends). Some scientists even believe that you could travel half way to Proxima Centauri before you truly leave the Sun’s sphere of influence, meaning that you would have to essentially travel to the next star in order to leave our solar system.

A diagram showing the many layers of our solar system, including the mysterious Oort Cloud (via NASA)

This is Our Sun Compared to Truly Massive Stars.

VY Canis Majoris is one of the largest stars in our galaxy. Yes, “one of.” Ultimately, Canis Majoris isn’t the largest star that we’ve ever discovered. When it was first discovered some 200 years ago, we thought that it was actually two stars orbiting together in a binary system. Ultimately, this star is so large, if it were placed at the center of our solar system, it would extend beyond the orbit of Jupiter.

A comparison between the hypergiant, our sun and Earth’s orbit. (Credit: WikiMedia)

And Here’s a Black Hole Compared to Our Solar System.

OJ287 is one of the largest black holes in the known universe. If it were placed at the center of our solar system, its event horizon would swallow nearly everything is our Sun’s sphere of influence. All the planets, the asteroid belt, and (obviously) us. This beast is an estimated 18 billion solar masses and drifts through the cosmos some .

Oj 287, one of the largest black holes in the known universe. Image by Jaime Trosper/FQTQ

 

Here’s Another Way to See how Large Black Holes are.

 

The Largest Known Galaxy Compared to the Milky Way

Shown in this image is IC 1101: The single largest galaxy that has ever been found in the observable universe. It is located almost a billion light-years away. Just how large is it?  At its largest point, this galaxy extends about 2 million light-years from its core, and it has a mass of about 100-trillion stars. To give you some idea of what this means, the Milky Way is just 100,000 light-years in diameter, and IC 1101 is 2000x as massive. If our galaxy were to be replaced with this super-giant, it would swallow up both Magellanic clouds, the Andromeda galaxy, the Triangulum galaxy, and almost all the space in between. That is simply staggering.

This is The Observable Universe.

This is, well… everything. Everything we can see and observe anyway. What you’re looking at is a map of known galaxies and superclusters in the “observable” universe, with the gaps that lie between the structures contributing to the map’s cell-like structure. These gaps, or voids, are regions of space completely lacking in stars, galaxies, and clusters. The largest of these gaps (the Eridanus supervoid) is almost one billion light-years in totality.

Via WikiMedia

This is the Total Size of the Universe (?)

As you can imagine, some confusion arises when one considers the fact that the universe is not 13.8 billion light-years across—a number that corresponds with the age of the universe (which is 13.8 billion years old). By current estimates, it’s quite a bit larger, measuring in at a staggering size of 93 billion light-years across. And that’s just what we can see. What we can’t see may go on forever.

Image credit: Scale of the Universe