Imagine that you are sitting at your work desk sipping on a cup of steaming hot coffee and from your misty window, you watch the snowy white ornaments hanging off trees in your backyard. You are compelled to feel a shiver of cold run through your skin.
At this junction of imagination, I compel you to wonder about the coldest place on the Earth. Do you think of frosted expanses of land, tormenting temperatures and houses adorned in snow? Then, you’re quite spot-on.
But, now, I ask you to condense an image of the coldest place in the universe – an ever-expanding abyss with no center. What comes to your mind? Certainly not a glowing, light-radiating dying star. Yet, indeed, it is a seemingly bow-tie-shaped preplanetary nebula known as the ‘Boomerang Nebula’ that according to Guinness World Records is felicitated with the title of ‘the coldest place in the universe’.
In this article, we will talk about this naturally-occurring enigma and how it came to be cold enough to be deemed as the coldest spot in the cosmos.
The Coldest Place in the Universe
If you would like to take a trip to the coldest spot in the cosmos, you would have to cover a distance of approximately 5000 light years away from the Earth in the direction of the constellation of Centaurus. Then you would have to halt at the sight of a red and orange object that has gained a reputation in the meme world for resembling an Among Us Crewmate.
The identity of this astronomical object is not limited to its uncanny resemblance to the video game character, it is in fact a protoplanetary nebula.
To shed light on what a protoplanetary nebula is, we would have to begin by talking of a low-mass star in its concluding stages of life. As the star reaches its dying stage characterized by scant nuclear fuel in its core, it starts expanding into a red giant. Its outermost molecules start cooling and clumping into dust, this gas and dust is pushed outward by the core’s depleting energy.
Eventually, the core collapses into a hot, white dwarf. At this stage, the core emits ultraviolet light which causes the outward shroud of gases to glow and the object takes the appearance of a planetary nebula. In the final stage, the nebula expands away into space and the white dwarf is left behind to slowly cool down.
Our ‘Boomerang Nebula’ is in the early stages of turning into a planetary nebula – the dusty fog of the gas phase, so to say, and thus, it is called a pre- or proto-planetary nebula. It is expected to remain in this phase for a rather brief cosmic span of some thousand years (universal time!).
How Cold Is Boomerang Nebula?
To fully understand the extreme cold that is held in Boomerang Nebula, we would have to recapitulate the phenomenon of absolute zero. Absolute zero is the theoretically lowest possible temperature of matter at which it captures no heat whatsoever.
Although unobservable in nature, it is supposed to occur at 0 K temperature which is equivalent to –273.15 ℃ or –459.67 ℉.
The enigma surrounding Boomerang Nebula can be attributed to its chilling interior temperature of -272.15 ℃ or 1 Kelvin, which is but a degree warmer than absolute zero – making our nebulae a cosmic freezer indeed! This temperature means that the Boomerang Nebula is over five times colder than Oymyakon, Russia – the coldest place in the world where humans live permanently.
How Was the Coldest Place in the Universe Discovered?
In the year 1980, a lopsided curved nebula was observed by astronomers Keith Taylor and Mike Scarrott through the eyepiece of their ground-based telescope in Australia. Due to the rudimentary nature of their astronomical tool, they mistook the nebula to resemble the throwing tool or “boomerang” and thus, named it the Boomerang Nebula.
It was only later in 1995 that a team of astronomers led by Dr. Raghvender Sahai discovered the astonishing fact about the nebula which has made it an object of fascination and intrigue amongst researchers. The question now is how did they ascertain the temperature of a cosmic object?
It is undoubtedly impossible to stick a thermometer in such an object, however, the team was able to study radiations emitted by carbon monoxide gas particles present in the nebula using a Swedish ESO Submillimetre Telescope in Chile and thus, reliably calculated its extreme temperature.
Notably, the team also observed that the nebula was absorbing background radiation from the empty space surrounding it. The background radiation or Cosmic Microwave Background (CMB) radiation is left-over energy from the Big Bang which sets the minimum temperature of the cosmos to around -270.4℃ making it remarkably cold.
However, the absorption of this CMB radiation by the nebula confirmed that it is even colder than CMB temperature (and a frosty, chilly and unnerving, cosmic freezer by all means, if you ask me!)
Why Is Boomerang Nebula So Cold?
The plausible reason behind the extraordinarily cold temperature of Boomerang Nebula has been hypothesized by a crew of astronomers led by Dr. Sahai and his colleague Dr. Lars-Åke Nyman in a paper published in Astrophysical Journal (2017).
The paper was published after the team conducted measurements of the age, mass and kinetic energy of Boomerang Nebula, as well as the rate of outflow of gases from its center, using Atacama Large Millimeter/submillimeter Array (ALMA) – located in the Atacama Desert in northern Chile (2013).
Dr. Sahai proposed that the story of Boomerang Nebula began when as a red giant, it collided with another companion star. Ordinarily, when a red giant’s outer layers expand to form a preplanetary nebula and gases are expelled outward, a cooling effect occurs because fewer molecules cover a larger area.
However, in the case of Boomerang Nebula, the expansion of the outer layers of gas and dust occurs at a rate that is 10 times higher than what would have been observed had it not undergone collision with a binary companion star (i.e., it is impossible for a single, red giant star to produce!)
As stated by Dr. Sahai:
“The only way to eject so much mass and at such extreme speeds is from the gravitational energy of two interacting stars which would explain the puzzling properties of the ultra-cold outflow.”
It is indeed, this rapid expulsion of cosmic mass by the combined capacity of two stars to never before seen distances of about 120,000 AUs and the consequent outflow of gas and dust, that has made Boomerang Nebula ultra-cold (to the extent that is even cooler than CBM radiation!)
It is unfortunate, however, that this observed phase of Boomerang Nebula is rather short-lived and its days as the ‘coldest place in the known universe’ will eventually come to an end when it meets its destined fate of transitioning into a white dwarf (but more on that later!)
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Top 5 Coldest Places on Earth
All this talk about the coldest place in the universe seems incredibly unfathomable but what we humans can surely wrap our heads around is a list of teeth-chattering places right here on our planet Earth.
Most of the locations listed here are uninhabitable for humans – cold enough to freeze your skin like a popsicle and cause your breath to crystallize midair! So, pull your sweaters tighter around as we begin listing the coldest places in the world today:
1. Dome Fuji, Antarctica
Home to a Japanese research station, this dry and cold desert tops our list of the coldest places in the world. In August 2010, the lowest ever air temperature recorded on the planet was observed here at -92.3 °C. Temperatures in Dome Fuji can range between -30 °C being the warmest and -80 °C being the chilliest.
Although, there is nothing human-friendly about either of these temperatures, humans have managed to establish means of livelihood in this elevated region on the Antarctic plateau. Nonetheless, be warned of bone-chills if you ever plan to visit Dome Fuji!
2. Vostok Research Station, Antarctica
Established in 1957 by the Soviet Union, this research station is located above Antarctica’s largest sub-glacial lake. Ever since 1983, when Vostok Research Station recorded the frosty temperature of -89.2 ℃, it had been regarded as the coldest place ever until 2010.
It has been a location of prime interest for research on the polar ecosystem of Antarctica and records the lowest mean annual temperature of any weather station on the planet. Surprisingly, for being one of the coldest places, this region receives a lot of sunlight – more than 22 hours in the month of December.
3. Amundsen-Scott South Pole Station, Antarctica
With a recorded temperature range between -13.6° C and -82.8° C, this station located close to 3,000m above sea level is one of the coldest in the world. Established in 1956, the average population here is around 150 people.
As described by a scientist working in the Amundsen-Scott South Pole Station, winters here are close to intolerable:
“…will endure six months of darkness, cold below negative 100 degrees F, nothing but frozen food, and an isolation that can’t be matched anywhere on the planet.”
4. Denali, Alaska
Located more than 6000m above sea level, Denali is the largest mountain peak in North America. This mountain is a sight to behold and has temperatures to run away from – unless you have exceptionally thick skin and warmers!
The lowest recorded temperature here is -73.8 ℃ which is nothing short of frosty and chilly.
5. Verkhoyansk, Russia
A town housing over 1000 inhabitants where an average day involves people clad in thick fur hats and coats procuring drinking water by boiling blocks of ice, Verkhoyansk holds the title of the northern ‘Pole of Cold’.
This Russian town located in the Arctic circle is indeed the coldest region in the Northern hemisphere logging its lowest temperature of -69.8 ℃ in 1892.
The range of temperatures experienced by the town between 38 ℃ in the summers and around -69 ℃ in winters is unbelievably large, and it holds a Guinness World record for the same. The extreme cold in this region is attributed to the build-up of cold, dry air called the Siberian High.
The Mysterious Shape of Boomerang Nebula
Did you think that the mystery of our beloved Boomerang Nebula ends with its acclaimed chill? Think again!
It turns out that its shape has puzzled astronomers just as much as its chilling temperature. In 1980, when it was originally discovered, our Australian astronomer friends named it ‘Boomerang Nebula’ owing to the asymmetrical glowing shape they saw.
But then, in 1980, when a research group took its image with the NASA/ESA Hubble Space Telescope, they observed that it looked nothing like a boomerang! Instead, it looked akin to a bow tie this time.
If you see this Hubble image carefully, you would think it would have been more appropriate to call our cosmic object ‘Bow-tie nebula’ – with ghostly streaks of outward glow and faint arcs diffusing into a hazy bow-tie.
But you would be incorrect again! The group of astronomers that observed the nebula even more closely using the ALMA radio telescope in 2013 were knocked off their chairs when they saw that Boomerang Nebula was actually a diffused, rounder cloud of expelling dust and gas.
The double-loped shape that Hubble captured was merely a distortion of Earth’s light due to the heavy sprinklings of dust around the star. These dust chunks form a kind of ring around the nebula partially obscuring the light coming from the central star and thus, trick us with the bow-tie shape.
If your eyes are sharp, you would recognize this ALMA image from the tweets and memes shared by gamers!
The Future of Boomerang Nebula
Do you recall the cosmic thousand years that a low-mass star spends in the preplanetary nebula phase? Our Boomerang Nebula has already spent 1500 years propelling cosmic matter at nearly 100 miles per second, which means that it won’t be too long (or already has) before our beautiful star inevitably loses the ultra-coldness that has made it the ‘coldest place in the universe’.
But worry not, studies conducted on our cosmic boomerang have suggested that there may be more nebulae out there which would be acting as cosmic freezers, it is only a matter of finding them! Don’t believe me? Look at what Dr. Nyman from the Joint ALMA observatory in Chile said about this:
“We see this remarkable object at a very special, very short-lived period of its life. It’s possible these super cosmic freezers are quite common in the universe, but they can only maintain such extreme temperatures for a relatively short time.”Dr. Nyman
As for our beloved Boomerang Nebula, the central red giant star is expected to continue on its journey to becoming a planetary nebula shedding off its outer layers and forming a veil of dust and gas around.
This will be accompanied by the shrinkage of the star which will become hotter and warm up the nebula of gas around it accentuating its luminating glow.
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The extensive research conducted by astronomers on Boomerang Nebula has offered us precious information about the way stars die and a look into what might happen to our Sun in a few billion years. Scientists are hoping to reveal the fate of our Sun, wondering if it will also metamorphize into an unimaginably cold, gaseous nebula.
These findings have also provided invaluable insight into the interactions of stellar companions – the consumption of a binary companion by a dying larger star and the aftermath of their fate together fused into a cosmic freezer.
Learning about cosmological objects like Boomerang Nebula forms precursor to all that humans can know and explore the cosmos and its hidden secrets, especially of the binary companion systems lurking in space waiting to be found.
Even more so, it is a favorable remark on our capacity as humans to undertake the challenging task of uncovering nature’s tremendous workings. It has revealed the marvellous ability of instruments like ALMA to resolve the unseen in the cosmos and produce high-resolution information about puzzling objects in the expanded darkness of our universe. Only time will tell what more is out there.
Frequently Asked Questions (FAQs):
1. Can Hubble see the coldest place in the universe?
Yes, certainly it can. It was in fact using the Hubble Space Telescope in the late 90s that researchers R. Sahai, J. Trauger and the WFPC2 Science Team captured high-resolution images of Boomerang Nebula for the first time.
Hubble’s detailed image of the coldest spot in space revealed patterns and currents in the central star of the gaseous nebula which the ground telescope in 1980 could not expose. It was because of the bow-tie shape of Boomerang Nebula seen in Hubble images that astronomers believed that it should have been named “Bow-tie Nebula” and not after the boomerang.
2. Can the James Webb telescope see the coldest place in the universe?
No images of the Boomerang Nebula have been taken by the James Webb Telescope yet. But it is claimed to be 100 times more powerful than Hubble and can peer much farther and deeper into the secrets of the universe with its high-tech and more evolved production.
So, it is safe to assume that it can very well capture the coldest place in the universe, and with possibly much greater detail than Hubble did. Another ground to base this bet on is the fact that the James Web Telescope captured stunningly detailed images of the Orion Nebula very recently.
3. How do we know for certain that the Boomerang Nebula is the coldest place in the universe?
Boomerang Nebula is certainly the coldest place in the universe. A group of astronomers in 1995 successfully conducted the determination of its interior temperature to be 1 Kelvin or -272.15 ℃ by studying the radiation coming from its centre.
If such an astonishing and unimaginably low temperature which is a mere degree above absolute zero was not enough evidence in support of this claim, then the fact that it absorbs the background radiation or CMB made it apparent for the researchers. This is because only an object colder than CMB (2.725 Kelvin) can absorb its passing radiation.
4. Where’s the coldest place in the world?
The coldest place in the world is the Dome Fuji in Antarctica which only displaced Vostok Research Station from the title in 2010 after recording the lowest ever air temperature of -92.3 °C measured on our Earth.
The cold and dry desert located at an altitude of 3810m above sea level forms the site of the Japanese research station. In summers, the temperature witnessed in Dome Fuji does not rise above -30 ℃ and drops until -80 ℃ during the usual winters.
5. Are black holes cold inside?
The interior of black holes is freezing cold in stark contrast to the scorching heat on their outside. The temperature of black holes is by virtue of the Hawking radiation that they emit and according to Stephen Hawking’s analysis, it is inversely proportional to the mass of the black hole.
The temperature of supermassive black holes – the most massive black holes in the universe having mass that is millions of times the mass of the Sun is estimated to be 1.4 x 10-14 Kelvin. That is extremely cold, almost touching absolute zero!