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Stars by Jake Weirick on

15 Great Facts About Stars

A star is an astronomical object made up of a bright plasma spheroid that is held together by self-gravity. They are without a doubt the main characters in the vast number of galaxies in our visible universe and probably the rest of it however much there is.

Stars have been a big part of human lives even before we knew what they were. They were at the center of religious practices, used for navigation effectively, used to mark seasons and define calendars and some even use them to define personalities and tell fortunes (horoscopes).

In the modern day, Man has made it his mission to explore beyond the limits of our green planet. This exploration into our solar system has provided much-needed information on many things including stars.

So, let鈥檚 look at some great facts about these bright celestial bodies.

1. The Sun Is the Closest Star to Earth

The sun from the earth by James Day on

Unless you鈥檙e a vampire or a bat, I鈥檒l assume you鈥檙e familiar with and fond of the sun (in controlled amounts anyway). The sun is the celestial body that provides earth with light and heat. So next time you take a good photo during the day, don鈥檛 forget to appreciate it. The caption 鈥榮un came out鈥� comes to mind!

Located approximately 148.14 million kilometers from earth, it has a diameter of 1.3927 million km. The sun is categorized as a green-blue star because its peak wavelength is in the region of the spectrum where blue and green are in transition.

However, to the unaided human eye, the colors appear yellow or yellow-white. It is by far not the largest star. The sun appears massive since it鈥檚 the closest to us.

2. Stars are made of Gas

A star-forming region in the Large Magellanic Cloud by ESA/Hubble –

Stars are light spheres formed of plasma-which is a superheated gas laced with a magnetic field. They are mostly composed of hydrogen, which stars fuse at the center of their bodies.

The thermonuclear fusion of hydrogen into helium in a star鈥檚 core is what keeps it glowing for the majority of its active life. Moreover, the energy is released as heat and light that is radiated into space.

3. Stars Don鈥檛 Twinkle

鈥楾winkle twinkle little star鈥︹�� is a popular lullaby that was sung to us and we鈥檒l probably sing to the next generations. However, as happy and innocent as it is, it is responsible for the misconception that stars twinkle. They DON鈥橳!

Yes, when one looks up at the sky on a clear dark night, the stars appear to twinkle. Scientists propose that the Twinkling of the stars is due to a property of Earth鈥檚 turbulent atmosphere. The earth’s atmosphere has many layers with different densities.

As a result, the light is refracted, shifting in color and intensity. The effect of many refractions brings about the twinkling of the stars. If you could see stars above the earth鈥檚 atmosphere, the stars would not twinkle.

4. Stars Are Born

All stars are formed by the gravitational collapse of clouds majorly composed of cold molecular hydrogen, helium, and other heavier elements. When the cloud disintegrates, it divides into countless parts that will eventually form individual stars. The material congregates into a ball that collapses under its own gravity until it can start nuclear fusion at its core.

As the ball collapses and density increases, the gravitational energy converts into heat and temperature rises. Over time, stars convert some of their hydrogen into helium.

5. Stars Can Die

Death by Fey Marin on

Stars generally live longer compared to human beings. A star鈥檚 lifetime may range from tens of millions to billions of years. Both the evolution and death of the star depending on its mass. For much of their life, Stars fuse Hydrogen. The star first fuses helium, then carbon when hydrogen runs out. The energy released at higher levels of fusion causes the star to heat up.

Low-mass stars (like the sun) become red giants as they begin to burn helium in the core and develop a degenerate carbon-oxygen core later on the asymptotic giant branch. They eventually lose their outer layer and become a planetary nebula, leaving behind their core, in the form of a white dwarf.

Massive stars become supergiant and go on to fuse elements heavier than helium. They die when their cores collapse and they explode as supernovae.

6. The Sun Is a Middle-Aged Star

A star鈥檚 life depends on its mass. The greater the mass, the shorter the lifetime. A cool dwarf will continue to glow for billions of years while a really large star may barely exist for tens of millions of years.

So size isn鈥檛 all that after all! Our Sun is thought to be middle-aged at 4.5 billion years old. According to current estimates, the sun will shine 40% brighter in 3.5 billion years than it does today. The sun is approximated to die in about 6 billion years.

7. The Second Closest Star Is Proxima Centauri

Proxima Centauri by Hubble –

Apart from the Sun, Proxima Centauri is the star that is closest to Earth. It is about 4.2465 light-years (40.175 trillion kilometers) away. It would take around 150,000 years to arrive if traveling at the Space Shuttle鈥檚 orbital speed of 8 km/s (29,000 km/h). So, if we left right now, how many generations do you think we鈥檒l sire on our way?

Proxima is found in the Alpha Centauri System. The Southern Hemisphere and the most southern regions of the Northern Hemisphere provide the best views of the Alpha Centauri System.

8. There Are About 9,096 Stars Visible to The Naked Eye in The Sky

Stars in the night sky by Kristian Pikner –

Across the entire sky, 9,096 stars are visible with the unaided eye. You need a telescope to expose fainter stars than your eyes can perceive in order to view more.

On a particularly dark night, only 2,000 stars may be seen with the naked eye from anywhere on Earth. To do this, one must evade all sources of light pollution and the night must be moonless. The Milky way according to astronomers has about a trillion stars.

Around 100 million light years from Earth, in the M100 galaxy of the Virgo Cluster, is the furthest distance at which a single star has been detected.

9. Sirius Is the Brightest Star in Our Night Sky

Hubble Space Telescope image of Sirius A and Sirius B. The white dwarf can be seen to the lower left. The diffraction spikes and concentric rings are instrumental effects by NASA –

Sirius is the brightest star in our night sky. It is also the brightest star in the Canis Major constellation (Latin; Greater dog). It is located 8.3 light-years (7.8524063 x 10^13 km) from Earth. Sirius is found in a 2-star system and has Sirius B as its companion.

It is more than 25 times more luminous and has twice the mass of the Sun. Probably Rihanna should have gone with ‘shine bright like Sirius’.

Sirius B is a faint white dwarf star that is just somewhat less massive than the Sun. Ancient people observed Sirius to signal the change of the seasons and as a compass for lengthy maritime trips.

10. Stars Experience Different Phases of Life

Just like human beings and other living creatures, stars experience different phases between their birth and before they die. A stellar nebular may take two directions in the phases. One lifecycle is through massive stars that end up being red Supergiant then Supernova and finally either a black hole or a neutron Star.

The second life cycle is by becoming an average star. The next phase is becoming a red giant then a planetary Nebula then a White Dwarf.

11. Stars Are Classified According to Their Spectral Properties

B-class stars in the Jewel Box cluster (Credit: ESO VLT) by ESO/Y. Beletsky –

Various methods can be used to classify stars. One of the methods is through spectral properties. Spectral properties are the information contained in the light the stars radiate. The information includes their temperature, luminosities, and colors. 

Seven major categories invented by astronomer Annie Jump Cannon are used to classify stars. They are O, B, A, F, G, K, and M, respectively. The largest and hottest stars are those in the ‘O’ class, with temperatures over 30,000 掳C. The smallest and coldest stars are those in the ‘M’ family, with temperatures below 3,000 掳C.

The color of stars can range from red to white to blue. Red is the coolest color having a temperature range of less than 3,500 K. Stars, like our Sun, have a yellowish-white color and a temperature of roughly 6,000 Kelvin. The hottest stars are blue, with surface temperatures exceeding 12,000 Kelvin.

12. The Word Star Is Derived From 鈥渉鈧俿t岣梤鈥�

The word star comes from the Proto鈥擨ndo-European root 鈥渉鈧俿t岣梤鈥� which also means star. On further analysis; h鈧俥h鈧乻- (鈥渢o burn,鈥� also the origin of the word 鈥渁sh鈥�) + -t膿r (agentive suffix). Some scholars believe that the term is a borrowing from the Akkadian word 鈥渋star鈥� (Venus), although others doubt that assumption. Star shares root with words like; asterisk, astral, constellation, and Esther.

13. Stars Were Used in The Creation of Calendars

Calendar by Eric Rothermel on

Early astronomers recognized a difference between 鈥渇ixed stars鈥� and 鈥渨andering stars鈥�. 鈥淔ixed stars鈥� position does not change whereas 鈥渨andering stars鈥� move noticeably relative to the fixed stars over days or weeks.

Whereas 鈥渨andering stars鈥� shift visibly compared to the fixed stars over the course of days or weeks, 鈥渇ixed stars鈥� remain in the same place. Several ancient astronomers held the view that the stars were immutably fixed to a celestial sphere.

According to tradition, astronomers categorized prominent stars into asterisms and constellations. They used these groups to monitor the movements of the planets and estimate the position of the Sun which was helpful in designing traditional calendars. Calendars used to control agricultural practices were invented using the motion of the sun in relation to the background stars.

14. Stars Are Mostly Named in Arabic

Several stars were given Arabic names by Islamic astronomers in the Middle Ages. These names are still used today. Islamic astronomers also invented numerous astronomical instruments that could compute the positions of the stars. They established the first large observatory research facilities, primarily to create Zij star catalogs.

15. Some Stars Represented Important Deities

mythic figure by Daniels Joffe on

In ancient societies, certain constellations, the Sun, and other individual stars have their own myths. In ancient Greek, the 鈥淲andering Stars鈥�, known as planets represented important deities. Uranus and Neptune were both Greek and Roman gods.

Both planets were unknown in the ancient past due to their low brightness. Their names were assigned by later astronomers. Other planets’ names like Mercury, Venus, Mars, Jupiter, and Saturn were also god names.

To know more about these planets, see our article on the solar system.