The Sun’s pretty great. It gives us light and warmth to enjoy, sunsets to paint … and
makes life on Earth possible.
So you might be tempted to head out and explore that thing -- which we did, in an imaginary,
indestructible spaceship.
But if we hadn’t used that invincible ship, all that heat and radiation would have gotten
super deadly, super fast.
In a regular NASA EVA spacesuit, for example -- the kind that you would use for spacewalks
-- you’d probably die somewhere before you got halfway to the Sun.
But it wouldn’t be from the heat. It would be from the other kinds of radiation that
are constantly streaming out of the Sun in different forms.
Some of that radiation comes from high-energy protons, electrons, and alpha particles, which
are basically helium atoms without the electrons.
The spacesuit would help with that a little, because its thick fabric would block many
of those particles and most UV radiation.
But the Sun also emits more dangerous kinds of light, like X-rays and gamma rays.
Blocking a good amount of gamma and X-rays would mean you’d have to line the spacesuit
with a layer of lead.
Astronaut suits don’t normally have that, because lead would make them a lot heavier
and much more difficult to bring up into space in the first place, and also, I imagine, harder
to move around.
Since astronauts working on the International Space Station aren’t usually out for too
long, they’re pretty safe without it.
Floating toward the Sun means a LOT of radiation exposure, though – radiation that would
probably end up killing you sometime before you reached the halfway point by basically
destroying too many cells to keep your body going.
Halfway to the sun is still pretty far, though.
The ship used for the Apollo 10 mission to the moon was the fastest manned vehicle in
human history, moving more than eleven kilometers every second on its way back from the Moon
in 1969.
If you were going as fast as Apollo 10 at its fastest, it would still take two and a
half months to travel half of the 150 million kilometers between Earth and the Sun.
You could get a lot closer if you invented -- and wore -- a spacesuit that blocked out
all kinds of radiation except for infrared light, which is what we feel as heat.
Most spacesuits are designed to withstand temperatures up to about 400 Kelvin, and you’d
probably be fine until you got around 95% of the way to the Sun.
That’s when the suit would go from being a life-sustaining pocket of the universe just
for you... to a kind of personal pressure cooker.
That’s just 6.8 million kilometers away from the solar surface, which is pretty close!
Especially considering that the Sun’s surface is almost 6,000 Kelvin.
You could only get that close because there’s nothing in space to conduct or hold onto the
heat except for your body, meaning that the only thing heating you up would be the infrared
radiation hitting you directly.
The farther you are from the Sun, the less of its light hits you. So you’d have to
get pretty close before you’d start to feel the burn.
But you wouldn’t necessarily need to invent a whole new spacesuit to get that close; an
ordinary spaceship would do.
It would be able to withstand higher temperatures, sure, but it would also be better at absorbing
heat than you are, and those two factors would pretty much cancel each other out.
So you could still only get about 95% of the way to the Sun before the ship started melting
-- a five month trip if you were going as fast as Apollo 10.
So I hope you were planning on bringing a good book or two on your way to your fiery
demise.
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