How old is our Solar System

How old is our Solar System?

It is a query that has been lingering in the minds of millions. For several years, it remained a mystery. But, science has studied several theories and meteorites to seek an answer. 

And through radioactive dating techniques and daughter isotopes. So, they have found that the solar system is much older than human imagination. But let’s delve deeper before knowing the numerical age. Keep scrolling.

How did scientists find the age of the solar system?

The website of USGS or United States Geological Survey has much detailed material. It is about how scientists calculated the age of the solar system. So, the basic part is that all material radioactivity becomes a stable isotope in the end. 

While some elements decay in nanoseconds, others live for over 100 billion years. This survey had its focus on studying naturally-occurring minerals. Also, such minerals have half-lives of around seven hundred million to a hundred billion years. 

What are these dating techniques called? They are radiometric dating. The roots of this system are in physics. So, the techniques can measure the last time a rock was either disturbed or melted. This sufficient disturbance could re-homogenize the radioactive elements. 

Through this dating procedure, scientists found the aggregate age of meteorites. It is around 4.6 billion years. Also, the earth-bound rocks are 4.3 billion years old. 

As per the reports of USGS, there was not one rock that wasn’t altered by the Earth’s tectonic plates. So with that, they hoped to refine the age of the planet Earth in the coming years.

What is Gravitational collapse?

Before getting molded into cleaner planets, every matter scrap belonged to a gigantic nebula. So, the solar system took birth from a floating interstellar cloud. Also, the huge cloud was made up of hydrogen, dust, and gases. 

Once the structure became gravitationally unstable, it began to collapse. But why did that happen? According to experts, here’s a possible reason. An exploding star or nearby supernova sent shock waves through space. 

Then, because of gravity, gas and dust continued to tug to the cloud’s center. Hence, the dense and hot core.

Gravitational collapse of a massive star, resulting in a Type 2 supernova (credit Wikipedia)

Beginning of the solar system

When the early solar nebula’s gases began to cool, something happened. aluminum and calcium were the first two materials to become solid particles. 

Over time, other solid particles too formed clusters. They kept enhancing in size and formed asteroids, comets, and later, planets. For a long time, astronomers have given thought to the oldest asteroids of the solar system. 

According to many, these rock bodies should be more enriched in aluminum and calcium. However, nothing like that has been found to date. 

In 1969, the Allende meteorite showed some inclusions rich in aluminum and calcium. However, it took around forty years for the inclusions spectra to be discovered. They extrapolate to the older asteroids in orbit all around the Sun

Astronomer Jessica Sunshine and her colleagues compiled these studies. Then, with the support of the National science foundation and NASA, she made this discovery.

Pac-man nebula

The Asteroid belt

There were some rocks that could not be pulled strongly by the planets. So, these remained behind as asteroids. They scattered all through the solar system without any home. 

In the area between Jupiter and Mars, many of these rocks orbit the Sun. It is known as the asteroid belt. Ceres is the largest belt with a diameter of around 600 miles. 

According to an astronomer, Tim Gregory, here’s what the asteroids mean. They are debris from the rocks left behind from the planet’s formation era. It was nearly four billion years ago.

Asteroid belt (credit wikimedia)

To scientists, these rocks are extremely valuable. 

They contain material that planets, including Earth, were made of in the first place. But got frozen in time. When these rocks are thoroughly studied, they speak volumes about the condition in the beginning. It was when the planets were still getting formed.

Time scales and size of the solar system

The Earth takes revolutions around the Sun at around 150 million km distance. It is also equivalent to 93 million miles! Next, the planets have nearly circular orbits. They measure from 1/3rd to thirty times the Earth’s orbit size. 

The innermost planet is Mercury. It orbits the Sun in nearly three months. On the other hand, it takes 165 days for Neptune. In short, the Sun contains the maximum mass of the complete solar system. And that is 99.9 percent.

But then, how old is the Universe?

According to science, the Universe is believed to be created around 13.7 billion years ago. Thorium-232 and uranium-238 are the two elements found in meteorites. Also, they have long lives. So, after measuring them, science has reached conclusions. 

Experts claim that these radioactive elements were added to the milky way around the same time. Further, one can say something about the galaxies and other large structures from these measurements. They got created quite quickly after the Big Bang happened.

And what about Pluto?

Pluto was the 9th planet for a long time. It was named after the underworld’s Roman god. However, it got demoted to the status of the dwarf planet in 2006. 

That’s because Pluto failed on the third criteria. It did not have a clear neighborhood. So, Pluto stays in the Kuiper Belt. It is a vast region way beyond Neptune and contains infinite space objects. 

Pluto as seen from the New Horizons spacecraft in 2015 at a distance of 476,000 miles
Pluto as seen from the New Horizons spacecraft in 2015 at a distance of 476,000 miles

Conclusion

The solar system began life as a swirling, vast cloud of dust and gas. It twisted through the cosmos without form or direction. So, the answer is the solar system is 4.6 billion years old. It was the huge cloud that became the Sun

Several processes gave birth to the solar system. It is believed that there are 181 moons and infinite asteroids in the entire structure. And do not forget the eight planets!

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