NASA: Less Than 1% Chance That Asteroid 2013 TV135 Will Hit Earth In 2032

Diagram of the orbit of orbit of asteroid 2013 TV135 (in blue), which scientists are 99.998% certain will not hit Earth. Calculations are based on one week of observations since the asteroid's discovery Oct. 8, and astronomers expect further observations will reduce or eliminate the observed impact probability. Credit: NASA/JPL-Caltech

We’ll skip straight to the good news: NASA says Earth is likely safe from Asteroid 2013 TV135. Calculations put the newly discovered asteroid’s chances of hitting the planet in 2032 at incredibly small — 1 in 63,000 — despite some alarmist news reports.

“To put it another way, that puts the current probability of no impact in 2032 at about 99.998 percent,” stated Don Yeomans, manager of NASA’s Near-Earth Object Program Office.

“This is a relatively new discovery. With more observations, I fully expect we will be able to significantly reduce, or rule out entirely, any impact probability for the foreseeable future.”

Asteroid 2013 TV135 in a series of images snapped by amateur astronomer Peter Lake.

The asteroid was first spotted on Oct. 8 by scientists at the Crimean Astrophysical Observatory in Ukraine. It’s 1,300 meters (400 feet) in diameter and cycles in an orbit that goes three-quarters of the way out to Jupiter, and then back again towards its closest approach near Earth’s orbit.

The asteroid came within 4.2 million miles (6.7 million kilometers) of Earth on Sept. 16. Amateur astronomer Peter Lake uploaded a video (which you can see above) based on a few pictures he took Oct. 17-18.

“Its important to remember that new asteroids (this one has only 9 days of arc) usually don’t stay on the Torino Scale (the risk register) for long, as further data updates increase the precision of the orbit, and usually quickly remove them as potential impactors,” Lake added in a blog post.

There are many, many international efforts to watch asteroid paths and disseminate the information to the public. One of them is NASA’s Asteroid Watch website, where you can get the latest information on nearby space rocks.

Students: Want To Get An Experiment Into Space? You Know You Want To

The International Space Station. Credit: NASA

Beer brewing in space? That’s what a preteen student will ask astronauts to do on the International Space Station soon. “By combining the four main ingredients (malt barley, hops, yeast, and water) of beer in space, will we be able to produce alcohol?” reads the research proposal from Michal Bodzianowski. If you follow the link, you can see how this also has medical applications on station, as alcohol can disinfect wounds.

Michal was a selectee in last year’s Student Spaceflight Experiments Program, which we’ve written about before. The program now has a new call for proposals.

Michal Bodzianowski with his experiment, which is intended to produce beer in space (if possible.) The experiment has medical applications as alcohol can be used for sterilization. Credit: SSEP
Michal Bodzianowski with his experiment, which is intended to produce beer in space (if possible.) The experiment has medical applications as alcohol can be used for sterilization. Credit: SSEP

“Each participating community will be provided a real microgravity research mini-laboratory capable of supporting a single experiment, and all launch services to fly it to the space station in fall 2014,” a press release stated.

The design competition, the release added, “allows student teams to design and formally propose real experiments vying for their community’s reserved mini-lab on space station. Content resources for teachers and students support foundational instruction on science in microgravity and experimental design.”

Inquiries must be sent by Nov. 20, and participating communities must sign up by Feb. 17, 2014. Final selection will take place in May.

For more information, you can visit the Student Spaceflight Experiments Program website. The program has participation from the National Center for Earth and Space Science Education, the Arthur C. Clarke Institute for Space Education, and NanoRacks.

Below is SSEP’s description of the five categories of participation:

  • Pre-College (the core focus for SSEP) in the U.S., (grades 5-12), with school districts—even individual schools—providing a stunning, real, on-orbit RESEARCH opportunity to their upper elementary, middle, and high school students (Explore the 60 communities that participated in the first six flight opportunities to date)
  • 2-Year Community Colleges in the U.S., (grades 13-14), where the student body is typically from the local community, providing wonderful pathways for community-wide engagement
  • 4-Year Colleges and Universities in the U.S., (grades 13-16), with an emphasis on Minority-Serving Institutions, where the program fosters interdisciplinary collaboration across schools and departments, and an opportunity for formal workforce development for science majors
  • Communities in the U.S. led by Informal Education or Out-of-School Organizations, (e.g., a museum or science center, a home school network, a scout troop), because high caliber STEM education programs must be accessible to organizations that promote effective learning beyond the traditional classroom
  • Communities Internationally: in European Space Agency (ESA) member nations, European Union (EU) member nations, Canada, and Japan, with participation through NCESSE’s Arthur C. Clarke Institute for Space Education. Communities in other nations should explore the potential for their participation by contacting the Institute at http://clarkeinstitute.org

Tilt-A-Whirl! A Tale Of Strange Planetary Orbits In Kepler-56

Artist's conception of Kepler-56, which has two planets orbiting at a tilt to their star despite the fact that scientists found no bigger gas giant planet to alter their orbits. Credit: Daniel Huber/NASA's Ames Research Center.

A faraway group of planets is puzzling scientists. Newly reported Kepler-56’s system has three planets — two smaller ones close by, and a much larger one further out. The inner planets are orbiting at a tilt to the equator of the host star.

Scientists have seen that tilt before in other systems, but they thought you would need a “hot Jupiter” — a huge gas giant planet close to the star — to make that happen. Here, that’s not the case. The outer planet’s gravity, distant as it is, is pulling the two planets into their tilted orbits.

“This is a very puzzling result that is sure to challenge our understanding of how solar systems form,” stated co-author Tim Bedding, a physics researcher at the University of Sydney.

Kepler-56 is 3,000 light-years away from Earth and has a mass about 30% greater than that of our Sun. As the name implies, astronomers used the Kepler space telescope to make the discovery.

You can read more details in the Oct. 18 edition of Science.

Sources: Iowa State and University of Sydney

India’s First Mars Mission Set to Blast off Seeking Methane Signature

Graphic outlines India’s first ever probe to explore the Red Planet known as the Mars Orbiter Mission (MOM). It could liftoff as early as Oct. 28 from the Satish Dhawan Space Centre SHAR, Srihairkota, India. Credit: ISRO

India is gearing up for its first ever space undertaking to the Red Planet – dubbed the Mars Orbiter Mission, or MOM – which is the brainchild of the Indian Space Research Organization, or ISRO.

Among other objectives, MOM will conduct a highly valuable search for potential signatures of Martian methane – which could stem from either living or non living sources. The historic Mars bound probe also serves as a forerunner to bolder robotic exploration goals.

If all goes well India would become only the 4th nation or entity from Earth to survey Mars up close with spacecraft, following the Soviet Union, the United States and the European Space Agency (ESA).

The 1,350 kilogram (2,980 pound) orbiter, also known as ‘Mangalyaan’, is slated to blast off as early as Oct. 28 atop India’s highly reliable Polar Satellite Launch Vehicle (PSLV) from a seaside launch pad in Srihanikota, India.

India’s first ever probe to explore the Red Planet known as the Mars Orbiter Mission (MOM), is due to liftoff as early as Oct. 28 from the Satish Dhawan Space Centre SHAR, Srihairkota, India. Credit: ISRO
India’s first ever probe to explore the Red Planet known as the Mars Orbiter Mission (MOM), is due to liftoff as early as Oct. 28 from the Satish Dhawan Space Centre SHAR, Srihairkota, India. Credit: ISRO

MOM is outfitted with an array of five science instruments including a multi color imager and a methane gas sniffer to study the Red Planet’s atmosphere, morphology, mineralogy and surface features. Methane on Earth originates from both biological and geological sources.

ISRO officials are also paying close attention to the local weather to ascertain if remnants from Tropical Cyclone Phaillin or another developing weather system in the South Pacific could impact liftoff plans.

The launch target date will be set following a readiness review on Friday, said ISRO Chairman K. Radhakrishnan according to Indian press reports.

India’s Mars Orbiter Mission (MOM) spacecraft being prepared for a prelaunch test at Satish Dhawan Space Centre SHAR, Srihairkota. Credit: ISRO
India’s Mars Orbiter Mission (MOM) spacecraft being prepared for a prelaunch test at Satish Dhawan Space Centre SHAR, Srihairkota. Credit: ISRO

‘Mangalyaan’ is undergoing final prelaunch test and integration at ISRO’s Satish Dhawan Space Centre SHAR, Srihairkota on the east coast of Andhra Pradesh state following shipment from ISRO’s Bangalore assembly facility on Oct. 3.

ISRO has already assembled the more powerful XL extended version of the four stage PSLV launcher at Srihairkota.

MOM’s launch window extends about three weeks until Nov. 19 – which roughly coincides with the opening of the launch window for NASA’s next mission to Mars, the MAVEN orbiter.

The upcoming Nov. 18 blastoff of NASA’s new MAVEN Mars orbiter was threatened by the US Federal Government shutdown when all launch processing work ceased on Oct. 1.  Spacecraft preps had now resumed on Oct. 3 after receiving an emergency exemption. MAVEN  was unveiled to the media, including Universe Today, inside the cleanroom at the Kennedy Space Center on Sept. 27, 2013. With solar panels unfurled, this is exactly how MAVEN looks when flying through space.  Credit: Ken Kremer/kenkremer.com
The upcoming Nov. 18 blastoff of NASA’s new MAVEN Mars orbiter was threatened by the US Federal Government shutdown when all launch processing work ceased on Oct. 1. Spacecraft preps had now resumed on Oct. 3 after receiving an emergency exemption. MAVEN was unveiled to the media, including Universe Today, inside the cleanroom at the Kennedy Space Center on Sept. 27, 2013. With solar panels unfurled, this is exactly how MAVEN looks when flying through space. Credit: Ken Kremer/kenkremer.com

MAVEN’s on time blastoff from Florida on Nov. 18, had been threatened by the chaos caused by the partial US government shutdown that finally ended this morning (Oct. 17), until the mission was granted an ‘emergency exemption’ due to the critical role it will play in relaying data from NASA’s ongoing pair of surface rovers – Curiosity and Opportunity.

NASA is providing key communications and navigation support to ISRO and MOM through the agency’s trio of huge tracking antennas in the Deep Space Network (DSN).

As India’s initial mission to Mars, ISRO says that the mission’s objectives are both technological and scientific to demonstrate the nation’s capability to design an interplanetary mission and carry out fundamental Red Planet research with a suite of indigenously built instruments.

MOM’s science complement comprises includes the tri color Mars Color Camera to image the planet and its two moon, Phobos and Diemos; the Lyman Alpha Photometer to measure the abundance of hydrogen and deuterium and understand the planets water loss process; a Thermal Imaging Spectrometer to map surface composition and mineralogy, the MENCA mass spectrometer to analyze atmospheric composition, and the Methane Sensor for Mars to measure traces of potential atmospheric methane down to the ppm level.

It will be of extremely great interest to compare any methane detection measurements from MOM to those ongoing from NASA’s Curiosity rover – which found ground level methane to be essentially nonexistent – and Europe’s planned 2016 ExoMars Trace Gas Orbiter.

MOM’s design builds on spacecraft heritage from India’s Chandrayaan 1 lunar mission that investigated the Moon from 2008 to 2009.

The 44 meter (144 ft) PSLV will launch MOM into an initially elliptical Earth parking orbit of 248 km x 23,000 km. A series of six orbit raising burns will eventually dispatch MOM on a trajectory to Mars by late November, assuming an Oct. 28 liftoff.

Following a 300 day interplanetary cruise phase, the do or die orbital insertion engine will fire on September 14, 2014 and place MOM into an 377 km x 80,000 km elliptical orbit.

NASA’s MAVEN is also due to arrive in Mars orbit during September 2014.

The $69 Million ‘Mangalyaan’ mission is expected to continue gathering measurements at the Red Planet for at least six months and perhaps ten months or longer.

Ken Kremer

Hubble’s Latest View Shows Comet ISON Still Intact, Fairly Average

Hubble's view of Comet ISON on Oct. 9, 2013. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

We’ve been showing images of Comet ISON from amateur astronomers around the world, but now that NASA is back from the government shutdown, here’s more proof that the comet is still intact and has not disintegrated … despite some predictions to the contrary. This image was taken on October 9.

NASA explains:

In this NASA Hubble Space Telescope image taken on October 9, the comet’s solid nucleus is unresolved because it is so small. If the nucleus broke apart then Hubble would have likely seen evidence for multiple fragments.

Moreover, the coma or head surrounding the comet’s nucleus is symmetric and smooth. This would probably not be the case if clusters of smaller fragments were flying along. What’s more, a polar jet of dust first seen in Hubble images taken in April is no longer visible and may have turned off.

This color composite image was assembled using two filters. The comet’s coma appears cyan, a greenish-blue color due to gas, while the tail is reddish due to dust streaming off the nucleus. The tail forms as dust particles are pushed away from the nucleus by the pressure of sunlight. The comet was inside Mars’ orbit and 177 million miles (284 million km) from Earth when photographed.

So, its not disintegrating, its not a three-piece body, its not a UFO… instead Comet ISON is turning out to be a rather average, ordinary comet. How has this comet sparked predictions that have gone from “bright as the full moon” to “disintegrating as we speak,” asked Josh Sokol from the Hubble ISON blog? “Simply put, ISON peaked early. When it was first discovered, way out past Jupiter, ISON was really bright,” Sokol wrote. “Extrapolated, those first data points made ISON look like it would shine even more as it got closer — and when it didn’t, the coverage seesawed back toward calling ISON a total bust.”

But ISON is still en route to the Sun. It will pass closest to the Sun on November 28, and if it remains intact after that close pass, it will make its closest approach to Earth on December 26, at a distance of 39.9 million miles (64 million km).

NASA is having a live Hangout with Hubble comet scientists to discuss the new image and latest research findings about ISON today (Oct. 17) at 4 p.m. EDT (20:00 UTC).

Update: here’s the replay:

Also, check out the Comet ISON Toolkit from NASA

Sources: HubbleSite, Hubble ISON blog

Topsy-Turvy Aurora Caught On Astronaut’s Camera

"The pic doesn't do the northern lights justice. Covered the whole sky. Truly amazing!" wrote NASA astronaut Mike Hopkins on Twitter Oct. 9.

Isn’t that aurora facing the wrong way? Not if you’re in space!

NASA astronaut Mike Hopkins tweeted this picture from his perch on the International Space Station a few days ago. He sounds jazzed to be on his first mission: “Can’t believe this is really me from the Cupola and that I’ve been in space for almost 3 weeks now!” he wrote on Twitter Oct. 15.

We’d be pretty excited, too! Luca Parmitano (from the European Space Agency) is also on his first trip into space. In between their many experiments, the rookies must relish the opportunity to take pictures of the view. Which image of theirs below is your favorite? Did we miss any notable shots? Let us know in the comments.

"Blue liquid silk folds and unfolds in the #Caribbean." European Space Agency astronaut Luca Parmitano, Oct. 16, 2013. (Twitter)
“Blue liquid silk folds and unfolds in the #Caribbean.” European Space Agency astronaut Luca Parmitano, Oct. 16, 2013. (Twitter)
"Not something you see every day first hand.  With features like this, Dubai stands out from 260 miles up." NASA astronaut Mike Hopkins, Oct. 14, 2013. (Twitter)
“Not something you see every day first hand. With features like this, Dubai stands out from 260 miles up.” NASA astronaut Mike Hopkins, Oct. 14, 2013. (Twitter)
"The sculpted mountains of the Iranian deserts." European Space Agency astronaut Luca Parmitano, Oct. 15, 2013. (Twitter)
“The sculpted mountains of the Iranian deserts.” European Space Agency astronaut Luca Parmitano, Oct. 15, 2013. (Twitter)
"What remains of Hurricane Phailin after it reached land." European Space Agency astronaut Luca Parmitano, Oct. 13, 2013. (Twitter)
“What remains of Hurricane Phailin after it reached land.” European Space Agency astronaut Luca Parmitano, Oct. 13, 2013. (Twitter)

And of course, they’re grinning like crazy up there.

"Impossible not to smile with such a view!" European Space Agency astronaut Luca Parmitano, Oct. 16, 2013.
“Impossible not to smile with such a view!” European Space Agency astronaut Luca Parmitano, Oct. 16, 2013. (Twitter)
"Can't believe this is really me from the Cupola and that I've been in space for almost 3 weeks now!" NASA astronaut Mike Hopkins, Oct. 15, 2013. (Twitter)
“Can’t believe this is really me from the Cupola and that I’ve been in space for almost 3 weeks now!” NASA astronaut Mike Hopkins, Oct. 15, 2013. (Twitter)

An Incredible View of Saturn that Could Only Be Seen by a Visiting Spacecraft

Saturn and its rings, as seen from above the planet by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute. Assembled by Gordan Ugarkovic.
Saturn and its rings, as seen from above the planet by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute/Gordan Ugarkovic

So what did NASA do during the US government shutdown? You can’t just turn off spacecraft that are operating millions of miles away, so missions like the Mars rovers and the Cassini spacecraft at Saturn continued to send back images to Earth during the 16 days that most of NASA wasn’t up and running like usual. On October 10, 2013, as Cassini flew high above the planet’s equatorial plane, the spacecraft’s camera took 36 images of Saturn, a dozen each using the various red, green, and blue filters used to create color images. The images were transferred back to Earth and put on the Cassini raw images page. Gordan Ugarkovic from Croatia, and a member of the image editing wizards at UnmannedSpaceflight.com, grabbed the raw files, processed them, then assembled the images into this jaw-dropping mosaic.

This is a view from Saturn that we could never get from Earth; only a spacecraft orbiting the planet could take it. You can see the north pole and the swirling maelstrom of clouds that creates the hexagonal polar vortex, the thin bands in Saturn’s atmosphere, and — of course — what really stands out is the incredible view of Saturn’s rings. To see the original 3 MB version, see this page on UMSF.

“You shouldn’t be surprised to see processing artifacts here and there,” cautioned Ugarkovic via email to Universe Today. “It is, after all, based on raw JPEG images only.”

See more of Gordan’s work at his Flickr page.

You can read more details about this from Emily Lakdawalla at the Planetary Society, or Phil Plait at Bad Astronomy/Slate.

But in the words of UMSF’s Astro0, “That’s the sort of view I’ve dreamed I would only ever see in a science fiction movie or if we had some kind of amazing futuristic spacecraft orbiting around that distant ringed planet….WAIT! We do!”

For more of what NASA did during the shutdown, Bill Dunford at Riding With Robots put together a great summary, quoting the @SarcasticRover that “You can’t shut down awesome.” Bill started the #ThingsNASAMightTweet hashtag that reminded everyone of all the things NASA does, but they couldn’t tweet about during the shutdown. People from around the world chimed in, adding what was important to them about NASA, and as of today, tweets with that hashtag have passed 27 million impressions.

Here’s A Nine-Billion-Year Old Gravitational Lens In Space

A picture of the object J1000+0221, which demonstrates the most distant gravitational lens ever discovered. This Hubble picture shows a normal galaxy's center region (the glow in the picture), but the object is also aligned with a younger, star-creating galaxy that is in behind. The object in the foreground pulls light from the background galaxy with gravity -- making rings of pictures. Credit: NASA/ESA/A. van der Wel

Here’s a picture of what deflected light looks like from 9.4 billion years away. This is the most faraway “gravitational lens” that we know of, and a demonstration of how a galaxy can bend the light of an object behind it. The phenomenon was first predicted by Einstein, and is a handy way of measuring mass (including the mass of mysterious dark matter.)

“The discovery was completely by chance,” stated Arjen van der Wel, who is with the Max Planck Institute for Astronomy in Heidelberg, Germany.

“I had been reviewing observations from an earlier project when I noticed a galaxy that was decidedly odd. It looked like an extremely young galaxy, but it seemed to be at a much larger distance than expected. It shouldn’t even have been part of our observing program.”

The alignment between object J1000+0221 and the object in behind is so perfect that you can see rings of light being formed in the image. Scientists previously believed this kind of lens would happen very rarely. This leaves two possibilities: that the astronomy team was lucky, or there are way more young galaxies than previously thought.

This schematic image represents how light from a distant galaxy is distorted by the gravitational effects of a nearer foreground galaxy, which acts like a lens and makes the distant source appear distorted, but brighter, forming characteristic rings of light, known as Einstein rings. An analysis of the distortion has revealed that some of the distant star-forming galaxies are as bright as 40 trillion Suns, and have been magnified by the gravitational lens by up to 22 times. Credit: ALMA (ESO/NRAO/NAOJ), L. Calçada (ESO), Y. Hezaveh et al.
This schematic image represents how light from a distant galaxy is distorted by the gravitational effects of a nearer foreground galaxy, which acts like a lens and makes the distant source appear distorted, but brighter, forming characteristic rings of light, known as Einstein rings. An analysis of the distortion has revealed that some of the distant star-forming galaxies are as bright as 40 trillion Suns, and have been magnified by the gravitational lens by up to 22 times. Credit: ALMA (ESO/NRAO/NAOJ), L. Calçada (ESO), Y. Hezaveh et al.

“Gravitational lenses are the result of a chance alignment. In this case, the alignment is very precise,” a press release on the discovery stated.

“To make matters worse, the magnified object is a starbursting dwarf galaxy: a comparatively light galaxy … but extremely young (about 10-40 million years old) and producing new stars at an enormous rate. The chances that such a peculiar galaxy would be gravitationally lensed is very small. Yet this is the second starbursting dwarf galaxy that has been found to be lensed.”

“This has been a weird and interesting discovery,” added van der Wel. “It was a completely serendipitous find, but it has the potential to start a new chapter in our description of galaxy evolution in the early universe.”

The research will be available soon in the Astrophysical Journal; in the meantime, check out a preprint version on Arxiv.

Source: Hubble European Space Agency Information Centre

NASA Celebrates Return To Work, But Shutdown’s Shadow Could Linger

A message on the NASA 360 Twitter feed the day employees returned to work after a 16-day government shutdown in October 2013.

After 16 days off the job, most employees at NASA returned to work today (Oct. 17). The good news came after a late-night deal by U.S. politicians to reopen government activities until Jan. 15 and raise the debt limit — originally expected to expire today — until Feb. 7. Democrats and Republicans were battling over the implementation of a new health care law; more details on how the deal was reached are available in this New York Times article.

During the shutdown, only mission-essential functions at NASA were completed except at areas such as the Jet Propulsion Laboratory, which are run by contractors. Twitter, Facebook and social media updates went silent. Missions were run on a needs-only basis, and for a while it looked as though the upcoming MAVEN mission to Mars might be delayed (although it got an exception due to its role as a communications relay for NASA’s rovers.)

So you can imagine the happiness on social media when NASA employees returned to work.

nasa_langley

Given the length of the shutdown,  not all work can just start immediately. Experiments have been left unattended for more than two weeks. Equipment needs to be powered back on. Cancelled meetings and travel arrangements need to, as it is possible, be rebooked.

At NASA’s Marshall Space Flight Center, spokesperson Don Amatore asked employees to be mindful of safety precautions, according to All Alabama. He also stated that “liberal leave” is in effect for employees today and on Friday, meaning that employees are able to take time off without requesting it beforehand — as long as their supervisors know.

Several Twitter reports from NASA contractors on Thursday also indicated that they were unsure if they would be coming back to work on that day, or at some point in the near future. The agency, however, was reportedly sending automated telephone updates to employees and contractors advising them to check with their supervisors for information.

The Stratospheric Observatory for Infrared Astronomy, or SOFIA, 747SP basks in the light of a full moon shining over California’s Mojave Desert. NASA photographer Tom Tschida shot this telephoto image on October 22, 2010 NASA Photo / Tom Tschida
The Stratospheric Observatory for Infrared Astronomy, or SOFIA, 747SP basks in the light of a full moon shining over California’s Mojave Desert. Photo / Tom Tschida

The long-term effects of the shutdown are still coming to light. Certain NASA researchers who planned Antarctic work this year may lose their entire field season. Also, some researchers using NASA or government telescopes missed their “window” of telescope time. “SOFIA remains grounded as a testament to stupidity. Europa keeps her secrets,” wrote Mike Brown,  a professor of planetary astronomy at the California Institute of Technology, on Twitter Oct. 13 about NASA’s Stratospheric Observatory for Infrared Astronomy.

Additionally, the S&P ratings agency noted that the U.S. economy lost $24 billion due to the shutdown, which is more than the initial $17.7 billion request for NASA’s budget in fiscal 2014. Given the agency is in the midst of budget negotiations and is worried about the viability of the commercial crew program, among other items, any long-term economic damage could hurt NASA for a while.

NASA and other government agencies also have only three months of relative stability until the government reaches another funding deadline. What do you think will happen next? Let us know in the comments.

How Will the Universe End?

How Will the Universe End?

The evidence that the Universe began with the Big Bang is very compelling. 13.8 billion years ago, the entire Universe was compressed into a microscopic singularity that grew exponentially into the vast cosmos we see today. But what does the future hold? How will the Universe end?

Astronomers have been pondering the ultimate fate of the Universe for thousands of years. In the last century, cosmologists considered three outcomes for the end of everything, and it all depended on the critical density of the Universe. If this critical density was high, then there was enough mutual gravity to slow and eventually halt the expansion. Billions of years in the future, it would then collapse in on itself again, perhaps creating another Big Bang. This is known as a closed Universe, and the final result is the Big Crunch.

If the critical density was low, then there wouldn’t be enough gravity to hold things together. Expansion would continue on forever and ever. Stars would die, galaxies would be spread apart, and everything would cool down to the background temperature of the Universe. This is an open Universe, and the end is known as the Big Freeze.

And if the critical density was just right, the Universe’s expansion goes on forever, but it’s always slowing down, reaching a dead stop in an infinite amount of time. This creates a Flat Universe… also a Big Freeze.

Fortunately, astronomers were able to measure the critical density of the Universe, using NASA’s WMAP spacecraft, and they discovered that the actual density of the Universe predicts a flat Universe. So that’s it, right? Of the three choices, the answer is #3.

Unfortunately, nature had other plans, and came up with a reality that nobody expected. In 1998, a team of astronomers were observing distant supernovae to get a sense of how fast the Universe is slowing down and they made an amazing discovery. Instead of decelerating, as predicted by the critical density of the Universe, the expansion of the Universe is actually speeding up.

Some mysterious force is pushing galaxies faster and faster away from each other, accelerating the expansion of the Universe. We now call this force “dark energy”, and for the time being, astronomers have no idea what it is. All we know is that it’s pushing the Universe apart. Distant galaxies are being accelerated away from us, and in trillions of years from now, they will cross the beyond the cosmic horizon and disappear from view. The evidence that we live in a vast Universe will disappear with them.

Galaxies from the Hubble Ultra Deep Field Image
Galaxies spinning farther and farther away from each other

But there’s a further unsettling possibility about dark energy. Maybe the expansion pressure will increase, eventually overwhelming gravity on a local level. Galaxies will get torn apart, and then Solar Systems, and eventually atoms themselves will be shredded by the increasing dark energy – this idea is known as the Big Rip.

So how will the Universe end? The force of dark energy will continue to accelerate the expansion of the Universe until distant galaxies disappear. Galaxies will use up all the gas and dust for stars and go dark, perhaps becoming black holes. Those black holes will decay and maybe matter itself will decay into pure energy. The entire Universe will become a cold, quiet place, where single photons are stretched across light years of space.

Don’t worry, though, that won’t be for quadrillions of years from now.