Milky way galaxy long exposure

The Milky Way, our spiral galaxy, captured in a long exposure that reveals its bright core and dusty arms.

About this subject

The Milky Way is a barred spiral galaxy that contains the Solar System. It is estimated to host between 100 and 400 billion stars, along with vast clouds of gas and dust forming its spiral arms. The Sun is located in one of the smaller arms, the Orion Arm, about 26,000 light-years from the galactic center, where a supermassive black hole known as Sagittarius A* resides.

Long exposure photography, common in astrophotography, captures the faint light of celestial objects invisible to the naked eye in light-polluted urban areas. In remote regions, such as deserts or high mountains, the Milky Way appears as a milky band crossing the sky, hence its name, derived from Greco-Roman mythology. In Brazil, it is popularly called "Estrada de Santiago" or "Caminho de São Tiago".

Culturally, the Milky Way has great significance: it was used by indigenous navigators for orientation, inspired countless legends, and in modern astronomy serves as a laboratory to study galactic evolution. Interestingly, the light we see today from distant stars traveled thousands of years to reach our eyes, a true journey through time.

Frequently Asked Questions

Why does the Milky Way appear as a band in the sky?

Because we observe the galaxy's disk from within it. When we look at the galactic plane, we see a dense concentration of stars, gas, and dust, forming the milky band.

What is the best time of year to observe the Milky Way in the Southern Hemisphere?

The galactic core is visible from March to October, peaking between June and August. On moonless nights far from light pollution, it can be seen with the naked eye.

How many stars are in the Milky Way?

Estimates range from 100 to 400 billion stars. The exact number is difficult to determine due to interstellar dust that obscures parts of the galaxy.