David Goggins
Former Navy Seal
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Bryan Cranston
Critical Thinking
Liv Boeree
International Poker Champion
Emotional Intelligence
Amaryllis Fox
Former CIA Clandestine Operative
Chris Hadfield
Retired Canadian Astronaut & Author
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The Big Freeze

The most widely accepted theory is that the universe will eventually come to an end. It will most likely do so trillions of years from now, when the entire span of the cosmos is empty and just a notch above absolute zero. We sometimes refer to this fate as the "Big Freeze."

Why, you ask? Out of respect for the law—specifically, the second law of thermodynamics, which tells us that total entropy (basically, chaos) in the order of the universe always increases. The second law of thermodynamics is one of the supreme laws in all of physics. If a scientist proposes a theory that violates it, he's in big trouble! 

Chaos and disorder: doesn’t that suggest a particularly violent end, rather than a big chill? Well, entropy doesn’t necessarily refer to dramatic destruction; it’s more about how stuff just tends to fall apart. Think about food sitting on your kitchen counter or in your refrigerator for an extended period of time: it will eventually rot. Or your car, which will begin to rust, decreasing its original strength. The example you're most familiar with is the way your body undergoes decline as it ages. Your vision and hearing get worse; you're not as strong as you used to be; your hair thins; you start to see wrinkles; and eventually your bodily processes begin to shut down.

Entropy is unique because it’s the only quantity in the physical sciences that indicates a particular direction for time (the "arrow of time"). It tells us that there is no hitting the rewind button to the beginning of the universe.

So the galaxies of the universe will eventually disintegrate, dead dwarf stars will drift away into the darkness along with the halts of neutron stars, and everywhere there will be black holes. There are an estimated 70 sextillion stars in the visible universe, organized in billions upon billions of galaxies. To put things in perspective, that’s 70 thousand million, or 7 followed by 22 zeros, and about 10 times as many stars as grains of sand on all the world’s beaches and deserts. A number so large, it’s almost impossible for us even to imagine.

Right now, we are in the Stelliferous age of the universe: the period in the life of the universe when there are still stars. Yet when the entire age of the universe is taken into consideration, it turns out that stars burn brightly only for a very short time. A trillion years from today, almost all the stars will have burned up all their nuclear fuel. A trillion years after that, even the black holes will have disintegrated; after that, even the protons themselves will begin to decay. The universe will then become a freezing mist of electrons and eventually approach absolute zero. At this point all motion stops...and that’s the Big Freeze.

Maybe we will be able to leave the universe before it gets too cold... You can watch a video clip of my Big Think interview (How to Escape to a Parallel Universe) which was recently voted one of Big Think's top ten videos of the first 100 days of 2010.

How do you think the Universe will end?

Let's hear your answer in the comments section for a chance to win an autographed 8x10 color photo. To be entered into the contest, simply answer the question (How do you think the Universe will end?) below by posting a comment in the comment box. You have to be a registered user of Big Think in order to post a comment. (REGISTER HERE if you haven't already.)

Winner of the autographed photo will be chosen on May 20th along with the winners from my other contest.

Good luck!

How accountability at work can transform your organization

If you don't practice accountability at work you're letting the formula for success slip right through your hands.

  • What is accountability? It's a tool for improving performance and, once its potential is thoroughly understood, it can be leveraged at scale in any team or organization.
  • In this lesson for leaders, managers, and individuals, Shideh Sedgh Bina, a founding partner of Insigniam and the editor-in-chief of IQ Insigniam Quarterly, explains why it is so crucial to success.
  • Learn to recognize the mindset of accountable versus unaccountable people, then use Shideh's guided exercise as a template for your next post-project accountability analysis—whether that project was a success or it fell short, it's equally important to do the reckoning.

What if Middle-earth was in Pakistan?

Iranian Tolkien scholar finds intriguing parallels between subcontinental geography and famous map of Middle-earth

Could this former river island in the Indus have inspired Tolkien to create Cair Andros, the ship-shaped island in the Anduin river?

Image: Mohammad Reza Kamali, reproduced with kind permission
Strange Maps
  • J.R.R. Tolkien himself hinted that his stories are set in a really ancient version of Europe.
  • But a fantasy realm can be inspired by a variety of places; and perhaps so is Tolkien's world.
  • These intriguing similarities with Asian topography show that it may be time to 'decolonise' Middle-earth.
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Giant whale sharks have teeth on their eyeballs

The ocean's largest shark relies on vision more than previously believed.

An eight-metre-long Whale shark swims with other fish at the Okinawa Churaumi Aquarium on February 26, 2010 in Motobu, Okinawa, Japan.

Photo by Koichi Kamoshida/Getty Images
Surprising Science
  • Japanese researchers discovered that the whale shark has "tiny teeth"—dermal denticles—protecting its eyes from abrasion.
  • They also found the shark is able to retract its eyeball into the eye socket.
  • Their research confirms that this giant fish relies on vision more than previously believed.
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A massive star has mysteriously vanished, confusing astronomers

A gigantic star makes off during an eight-year gap in observations.

Image source: ESO/L. Calçada
Surprising Science
  • The massive star in the Kinsman Dwarf Galaxy seems to have disappeared between 2011 and 2019.
  • It's likely that it erupted, but could it have collapsed into a black hole without a supernova?
  • Maybe it's still there, but much less luminous and/or covered by dust.

A "very massive star" in the Kinman Dwarf galaxy caught the attention of astronomers in the early years of the 2000s: It seemed to be reaching a late-ish chapter in its life story and offered a rare chance to observe the death of a large star in a region low in metallicity. However, by the time scientists had the chance to turn the European Southern Observatory's (ESO) Very Large Telescope (VLT) in Paranal, Chile back around to it in 2019 — it's not a slow-turner, just an in-demand device — it was utterly gone without a trace. But how?

The two leading theories about what happened are that either it's still there, still erupting its way through its death throes, with less luminosity and perhaps obscured by dust, or it just up and collapsed into a black hole without going through a supernova stage. "If true, this would be the first direct detection of such a monster star ending its life in this manner," says Andrew Allan of Trinity College Dublin, Ireland, leader of the observation team whose study is published in Monthly Notices of the Royal Astronomical Society.

So, em...

Between astronomers' last look in 2011 and 2019 is a large enough interval of time for something to happen. Not that 2001 (when it was first observed) or 2019 have much meaning, since we're always watching the past out there and the Kinman Dwarf Galaxy is 75 million light years away. We often think of cosmic events as slow-moving phenomena because so often their follow-on effects are massive and unfold to us over time. But things happen just as fast big as small. The number of things that happened in the first 10 millionth of a trillionth of a trillionth of a trillionth of a second after the Big Bang, for example, is insane.

In any event, the Kinsman Dwarf Galaxy, or PHL 293B, is far way, too far for astronomers to directly observe its stars. Their presence can be inferred from spectroscopic signatures — specifically, PHL 293B between 2001 and 2011 consistently featured strong signatures of hydrogen that indicated the presence of a massive "luminous blue variable" (LBV) star about 2.5 times more brilliant than our Sun. Astronomers suspect that some very large stars may spend their final years as LBVs.

Though LBVs are known to experience radical shifts in spectra and brightness, they reliably leave specific traces that help confirm their ongoing presence. In 2019 the hydrogen signatures, and such traces, were gone. Allan says, "It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion."

The Kinsman Dwarf Galaxy, or PHL 293B, is one of the most metal-poor galaxies known. Explosive, massive, Wolf-Rayet stars are seldom seen in such environments — NASA refers to such stars as those that "live fast, die hard." Red supergiants are also rare to low Z environments. The now-missing star was looked to as a rare opportunity to observe a massive star's late stages in such an environment.

Celestial sleuthing

In August 2019, the team pointed the four eight-meter telescopes of ESO's ESPRESSO array simultaneously toward the LBV's former location: nothing. They also gave the VLT's X-shooter instrument a shot a few months later: also nothing.

Still pursuing the missing star, the scientists acquired access to older data for comparison to what they already felt they knew. "The ESO Science Archive Facility enabled us to find and use data of the same object obtained in 2002 and 2009," says Andrea Mehner, an ESO staff member who worked on the study. "The comparison of the 2002 high-resolution UVES spectra with our observations obtained in 2019 with ESO's newest high-resolution spectrograph ESPRESSO was especially revealing, from both an astronomical and an instrumentation point of view."

Examination of this data suggested that the LBV may have indeed been winding up to a grand final sometime after 2011.

Team member Jose Groh, also of Trinity College, says "We may have detected one of the most massive stars of the local Universe going gently into the night. Our discovery would not have been made without using the powerful ESO 8-meter telescopes, their unique instrumentation, and the prompt access to those capabilities following the recent agreement of Ireland to join ESO."

Combining the 2019 data with contemporaneous Hubble Space Telescope (HST) imagery leaves the authors of the reports with the sense that "the LBV was in an eruptive state at least between 2001 and 2011, which then ended, and may have been followed by a collapse into a massive BH without the production of an SN. This scenario is consistent with the available HST and ground-based photometry."


A star collapsing into a black hole without a supernova would be a rare event, and that argues against the idea. The paper also notes that we may simply have missed the star's supernova during the eight-year observation gap.

LBVs are known to be highly unstable, so the star dropping to a state of less luminosity or producing a dust cover would be much more in the realm of expected behavior.

Says the paper: "A combination of a slightly reduced luminosity and a thick dusty shell could result in the star being obscured. While the lack of variability between the 2009 and 2019 near-infrared continuum from our X-shooter spectra eliminates the possibility of formation of hot dust (⪆1500 K), mid-infrared observations are necessary to rule out a slowly expanding cooler dust shell."

The authors of the report are pretty confident the star experienced a dramatic eruption after 2011. Beyond that, though:

"Based on our observations and models, we suggest that PHL 293B hosted an LBV with an eruption that ended sometime after 2011. This could have been followed by
(1) a surviving star or
(2) a collapse of the LBV to a BH [black hole] without the production of a bright SN, but possibly with a weak transient."

Future of Learning

Changing the way we grade students could trigger a wave of innovation

How students apply what they've learned is more important than a letter or number grade.

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