[♪ INTRO] Unfortunately, or maybe fortunately,  time machines have not been invented yet.

So scientists rely on other methods to figure out what the solar system was probably  like billions of years ago. And there is a new way to study our own  past if we can find a star that’s both close enough to us for us to study it and the same type of star as our Sun, but younger.

Astronomers can image that star to reveal what our Sun’s baby pictures would have looked like. While they don’t come in many shapes,  they mostly just come in the one shape, they do come in a lot of sizes, and those  sizes relate to other properties like their surface temperature, color, and luminosity. And astronomers often use these features to organize stars on a chart called an HR diagram.

Stars spend most of their lives in the middle band of this diagram known as the “main sequence.” They’re living their best lives, fusing hydrogen and producing energy that can go on  to support life on other planets. Our Sun is here, about halfway  through its ten billion year lifespan. Given its position on the diagram,  astronomers classify it a G2V star.

The G2 references the specific  combination of light wavelengths it emits, and everything in the main  sequence gets the Roman numeral V. Because it’s basically in the middle  of the diagram, that might suggest our Sun is “average,” but it is not. Way more stars, like up to 95% of  them, are less massive than the Sun.

Which means that their life cycles  don’t play out the same way. So if we want to study what our  Sun was like in the past, you know, to figure out how our solar system got here, astronomers need to find a solar analog,  a young star similar enough to our Sun and physically close enough  to get detailed data on it. This way scientists will be able to get  baby pictures from the Sun's younger cousin, which will approximate what pictures  of the Sun itself would’ve looked like if anyone had been around back then to take them.

And that is where a young star less  than 30 light-years away comes in. Kappa-1 Ceti. It’s a bit cooler, and a bit  less bright than our Sun is, making it a G5V star instead of a  G2V, but that’s not a deal-breaker.

Because stars actually get a little  hotter and a lot brighter as they age, and this baby star is only  about 650 million years old. That age is actually pretty  important because it corresponds to roughly the point in time in our solar  system’s history that life began on Earth. Baby stars are known for their  violent high-energy outbursts, like ultraviolet and X-ray radiation, which are a huge threat to the emergence  of life on their planets.

The radiation itself has enough  energy to destroy molecules that otherwise might have formed  something like a DNA molecule. And on a global scale, if the planet  doesn’t have a strong enough magnetic field to protect its atmosphere,  those rays can rip it to shreds. But it turns out that some  of that radiation may also be needed to chemically kick-start  the formation of organic molecules.

It breaks up nitrogen, carbon dioxide,  and water molecules in the atmosphere and forces them to recombine into new compounds, which could eventually go on to  make the building blocks of life. And in the Sun’s case, because it wasn’t  heating the Earth up as much back then, the creation of greenhouse gases could have helped keep things nice and  toasty while life was incubating. Kappa-1 Ceti was identified  at least two decades ago, to be a modern demonstration of what happened when the Sun was a baby as a  way to explore this process.

So in August 2021, a team of  astronomers published a paper in the Astrophysical Journal compiling a  bunch of data on Kappa-1 Ceti collected by different telescope missions that they translated into a new computer model of the star. More specifically, the star’s coronal wind, or the high-energy photons and charged  particles the star burps off into space, which then go on to interact  with any nearby orbiting planets. The model revealed a few results,  like the temperature of the corona, or the atmosphere of plasma around the  star, being around 6 million Kelvin.

And the density of the wind  was between 50 and 100 times greater than the Sun’s wind  currently is in its middle age. Kappa-1 Ceti is also spinning  way faster than the Sun. It rotates every nine days,  while the Sun rotates every 27.

That speedy rotation compresses the wind and forms a sort of spiral-looking wave of  plasma that rotates along with the star. At a distance of 1 AU, or how far the  Earth is from our Sun, that compressed wind exerts pressure on a planet’s  magnetic field 1300 times greater than what the Earth currently experiences  when our Sun has a hiccup. If kappa-1 Ceti had one of these  hiccups it would significantly distort the magnetic field of a baby Earth, creating geomagnetic storms in the atmosphere.

And because of that fast-spinning,  it would happen every four-ish days. Now this is only one snapshot  in the Sun’s alternative album, but it taught us things like how radiation could create organic molecules and more  about our Sun’s own life cycle. And the team already has their next steps  planned out for getting more pictures: the next target is a 100  million-year-old star called EK Draconis, which is spinning even faster and  throwing off even more radiation.

But they did also say their model  needs a little further tweaking to make sure it accurately reflects  the complexity of the situation. Ultimately, studies like these  will help astronomers figure out the habitability of exoplanets  around Sun-like stars. Ours managed to render Mercury, Venus, and Mars uninhabitable billions of  years ago, but Earth hung on, what contribution did the Sun’s violent past play in getting these different outcomes?

Only time and more pictures will tell. And you know what other pictures  showed us...the dark side of the Moon! These pictures were taken  with the Luna-3 probe and to commemorate the occasion we have  immortalized it as the pin of the Month.

You can take this tiny craft  home during the month of October at DFTBA.com/SciShow, because  when November rolls around, we will have a whole new pin ready for you. [♪ OUTRO]