Stars may seem like mystical, untouchable objects in the night sky, but could there actually be stars out there that are cold enough for humans to physically touch? This is an intriguing question that many people wonder about when gazing at the cosmos. In this article, we’ll explore the possibilities and realities around touching the stars.
How hot are stars generally?
The surface temperature of a star depends greatly on its size and classification on the main sequence. To put into perspective how hot stars really are:
- The sun’s surface temperature is about 5,500°C (9,980°F). Definitely not touchable for humans!
- Blue giant stars can reach temperatures over 30,000°C (54,000°F).
- Red dwarf stars, the smallest and coolest stars on the main sequence, have surface temperatures ranging from 2400°C to 3700°C (4300°F to 6700°F).
So you can see, even the coolest stars out there are still blazing hot compared to anything humans could withstand. But are there exceptions? Are there some stars out there that may actually be touchable? Let’s look into some possibilities.
The coldest stars: Brown dwarfs
Brown dwarfs are objects that are too large to be considered planets, yet not large enough to fuse hydrogen and sustain nuclear fusion reactions in their core like true stars. They typically have masses between 13 and 80 Jupiter masses.
Because they can’t sustain regular fusion, brown dwarfs cool and contract over time, becoming colder and smaller. Some brown dwarfs can have temperatures comparable to the human body!
- 2MASSI J0415195-093506 is a brown dwarf with an estimated temperature range of 212 – 366°F (100 – 186°C).
- WISE 0855−0714 is an ultracool brown dwarf with an approximate temperature of -10 to -13°F (-23 to -25°C).
So while still much colder than our Sun and other true stars, some brown dwarfs like WISE 0855−0714 do reach temperatures that humans could potentially withstand briefly with protection. But could we ever actually touch one?
Could we touch a brown dwarf?
Unfortunately, the chances are exceedingly slim that a human could ever get close enough to physically touch even the coldest brown dwarf. Here are some of the key challenges:
- Distance – The closest known brown dwarf, Luhman 16, is still 6.5 light years away. Even traveling at the speed of the fastest spacecraft humans have built (Parker Solar Probe, ~690,000 km/h), it would take over 18,000 years to reach this brown dwarf. And Luhman 16 is one of the rare nearby examples. Most other brown dwarfs are much further away.
- Atmosphere – Brown dwarfs are still very hot compared to outer space. Their atmospheres can reach 1,500°F (815°C), which would vaporize a human.
- Gravity – A brown dwarf may have gravity over 1,000 times that of Earth’s. We would be immediately pulled apart trying to land on one.
- Radiation – Brown dwarfs emit strong X-ray and ultraviolet radiation that is extremely hazardous to humans, even with shielding.
Due to these challenging conditions, there is no practical way humans could ever touch a brown dwarf directly. We may be able to briefly graze the upper layers of the atmosphere with a specialized space probe, but the bulk of the brown dwarf is far too extreme an environment for direct contact.
Could we touch a white dwarf?
White dwarfs are the remains of medium to low mass stars after they have exhausted their nuclear fuel. They are extremely dense and compact, packing a sun-like mass into an Earth-like volume. They also lack internal heating sources, so they gradually radiate their residual heat and cool over billions of years.
Because of this cooling, some white dwarfs eventually do reach touchable temperatures by human standards. However, yet again the challenges of distance and atmospheric conditions make direct contact impossible:
- The nearest known white dwarf is Sirius B, at 8.6 light years away, even more distant than the nearest brown dwarfs.
- White dwarfs have powerful gravitational fields that would crush a human instantly.
- They retain hot outer atmospheres as they cool, which would incinerate anything approaching.
So while white dwarfs do become cold enough to potentially touch on their surfaces, the distances and environmental challenges mean we’ll never actually be able to come into direct contact with one.
The coldest place in the universe: The Boomerang Nebula
If we can’t touch even the coolest stars and stellar remnants, is there anything out there we could touch? Well, planets and smaller bodies like asteroids are physically possible to reach and land on with the right equipment and technology.
But the coldest known place in the entire universe as we know it is the Boomerang Nebula, a protoplanetary nebula formed from gases ejected by a dying star. This nebula has been measured by the Herschel Space Observatory to have a temperature of -458°F (-272°C) – just barely above absolute zero! At this temperature, nearly all molecular motion comes to a stop.
While far too cold and distant (5,000 light years away) to actually touch, the Boomerang Nebula represents one of the coldest known environments in the entire cosmos. But practically speaking, there are no stars or stellar remnants that are even close to being touchable by human hands. The unfathomable distances, extreme gravities, and scorching temperatures make that an impossible dream. We’ll have to stick with just observing the stunning stars from afar for now.
Could advanced technology someday allow us to touch stars?
While physically touching a star may be firmly in the realm of science fiction with our current technology, could future advancements someday make this dream a reality? Theoretical concepts that may open a path include:
- Warp drives or wormholes – Space-time warping technology could potentially enable faster-than-light travel to reach distant stars in reasonable timeframes.
- Force fields – Energy shields could block radiation, heat, and gravitational force in close proximity to stars.
- Robotics – Heat and radiation-resistant robotic probes could potentially enter a star’s outer atmosphere for direct sampling.
- Stellar engineering – Radically advanced technology might even allow altering the process of stars themselves to cool them over time.
These kinds of futuristic concepts pose immense challenges and may not become reality for centuries, if ever. But the possibilities continue to inspire theoretical study and perhaps someday will enable us to conquer the immense obstacles that bar direct interaction with stars today. Still, we are likely many scientific leaps away from that point right now.
Conclusion
Stars undeniably capture our imaginations when gazing up at the beauty of the night sky. Their brilliance sparks a sense of wonder, and their vast distances make them seem almost mythic. While no stars are even remotely touchable with today’s technology, some cooled remnants like brown dwarfs and white dwarfs do reach temperatures that humans could potentially withstand under the right conditions.
But the reality is that the distances, gravitational forces, hazardous radiation and temperatures make actually touching any star or stellar remnant firmly in the realm of science fiction still today. Advancements may someday allow us to develop probes or mechanisms that could sample their outer layers, but our bodies will likely never come into direct contact with their surfaces. We are left to appreciate the beauty of the stars through observation for now. The cosmos contain many mysteries left to still uncover, but for the time being, direct contact with the fiery, fascinating stars must remain simply a dream.
Frequently Asked Questions
What is the hottest star?
The hottest known star is WR 102, a Wolf-Rayet star with a surface temperature of about 200,000 degrees Celsius or 360,000 degrees Fahrenheit.
What is the coldest star?
The coldest true star is TRAPPIST-1, an ultracool red dwarf star with a surface temperature around 2,550 degrees Celsius or 4,600 degrees Fahrenheit. Even cooler dwarf star candidates have been proposed but not confirmed.
How close would you have to be to touch a star?
You would have to be within the outer layers of the star’s atmosphere to physically touch the star’s gasses. But the extreme heat, radiation, gravity and other hazards make this impossible with any existing technology and unsurvivable for a human.
What is the closest star to Earth?
The closest star system to our solar system is the three-star Alpha Centauri system at 4.37 light years away. The closest individual star is Proxima Centauri at 4.24 light years away.
Could we send a probe to touch a star?
Potentially, yes, with future advances in materials science, robotics, and shielding technology, we may someday be able to send a probe capable of entering and sampling a star’s outer atmosphere. But we do not yet have the capability to build a probe that could withstand the extreme environment.
Final Summary
Stars are hot, distant objects that capture our imaginations when viewing the night sky. While too hot and far away to touch with current technology, some cooled remnants like brown dwarfs reach habitable temperatures. However, the distances, gravity, radiation and other hazards still prevent any actual physical contact by humans currently. Advanced technology may someday enable probes to sample a star’s outer atmosphere, but touching their surfaces remains firmly in the realm of science fiction for the time being.