Image by vector_corp on Freepik
| Planets |
Discovered |
|---|---|
| Mercury | Antike |
| Venus | Antike |
| Mars | Antike |
| Jupiter | Antike |
| Saturn | Antike |
| Uranus | March 13, 1781 |
| Neptune | September 23, 1846 |
A black hole is an astronomical object with such a strong gravitational pull that nothing, not even light, can escape it. There are three main classes: stellar-mass (a few to dozens of solar masses), intermediate-mass (100 to over 10,000 solar masses), and supermassive (100,000 to billions of solar masses).
Stellar-mass black holes form from collapsing massive stars, while supermassive black holes exist at galaxy centers. Intermediate-mass black holes were confirmed through gravitational wave detection in 2019. Black holes grow by accreting matter.
In 2019, the Event Horizon Telescope captured the first image of a black hole in the galaxy M87, weighing over 6 billion solar masses, 55 million light-years away.
Detailed article (NASA)
Stars are the most widely recognized astronomical objects, and represent the most fundamental building blocks of galaxies. The age, distribution, and composition of the stars in a galaxy trace the history, dynamics, and evolution of that galaxy.
Moreover, stars are responsible for the manufacture and distribution of heavy elements such as carbon, nitrogen, and oxygen, and their characteristics are intimately tied to the characteristics of the planetary systems that may coalesce about them.
Consequently, the study of the birth, life, and death of stars is central to the field of astronomy.
Detailed article (NASA)
This image of the nearby Spiral Galaxy M74, captured by the NASA/ESA Hubble Space Telescope, resembles festive lights on a holiday wreath and serves as an iconic reminder of the upcoming season. Bright knots of luminous gas illuminate the spiral arms, indicating a rich star-forming environment.
Messier 74, also known as NGC 628, is a stunning example of a spiral galaxy with magnificent design, observed almost face-on by Earth observers. Its perfectly symmetrical spiral arms emanate from the central core and are adorned with clusters of young blue stars and brightly pink regions of ionized hydrogen (hydrogen atoms that have lost their electrons). These regions of star formation exhibit an excess of light in the ultraviolet wavelength range.
Winding dust lanes run along the spiral arms, starting near the galaxy's core and extending along the entire length of the spiral arms. M74 is located approximately 32 million light-years away in the direction of the Pisces constellation, the Fish. It is the dominant member of a small group of about half a dozen galaxies known as the M74 Galaxy Group. In total, M74 is estimated to host around 100 billion stars, making it slightly smaller than our Milky Way.
Detailed article (NASA)
The light travels 3000000 km per second
The Earth, some 18 galactic years old, has completed a journey around the Milky Way during its 4.5 billion years of existence,
hurtling through interstellar space at 800,000 km/h.
In the centre of our galaxy there is a huge black hole called Sagittarius A*.it is thought to have the size of 4 million suns
We don't know exactly how many stars there are in our galaxy! It could be 100 billion, but it could also be 4 billion, because a large proportion of the stars are dark stars that are not so easy to recognise.