Category Archives: Solar System

20 Best Photos of Cassini’s voyage around Saturn

Launched on October 15, 1997, NASA’s Cassini spacecraft Notes 1 went into orbit around Saturn on July 1, 2004. Since then, it has taken thousands of photos of Saturn, the second-largest planet in the Solar System, its prominent rings, and moons. And on September 15, 2017, Cassini plunged into Saturn’s atmosphere and disintegrated. Here are the 20 most beautiful photos that the spacecraft has sent back to Earth during its 13-year voyage around the gas giant.

Cassini was destroyed by diving into the Saturn’s atmosphere on September 15, 2017. This method of disposal was planned to avoid potential biological contamination of Saturn’s moons, since Titan, Enceladus, and other icy moons of Saturn may harbor oceans and alien life.

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Now We Know When Stars Will Be Passing Close to the Sun

About 70,000 years ago, a wandering binary stellar system passed through the Solar System’s Oort cloudNotes 1, within 120,000 AU (0.58 pc; 1.9 ly) of the Sun. 70,000 years is just a blink of an eye compared to the Earth’s age, which is 4.543 billion years. Our ancestors were about to left Africa at that time. The binary system is dubbed as Scholz’s StarNotes 2, after its discoverer. Comets perturbed from the Oort cloud would require roughly 2 million years to get to the inner Solar System. So, in the distant future, some of these comets may hit the Earth and cause mass extinctions, like the “dinosaur killer” Chicxulub impactor which impacted a few miles from the present-day town of Chicxulub in Mexico around 66 million years ago.

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Total Solar Eclipse 2017 Images From Space

On Monday, August 21, an estimated 2 million to 7.4 million Americans traveled to see the first total solar eclipse in 99 years to go coast to coast in the United States, which went from Lincoln Beach, Oregon, to Charleston, South Carolina. But, some of them were unlucky, as the weather was overcast in some places. But, luckily for them (and for us), NASA captured some amazing and beautiful images of the eclipse and published them on their website.

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Huge Asteroid “3122 Florence” flyby video

On September 1, 2017, a potentially hazardous asteroid named 3122 Florence skimmed past Earth from a mere 4.4 million miles (7 million km) distance. The huge asteroid, which is around 2.7 mile (4.4 km) wide, was the “biggest object passed this close to Earth since the NASA program to detect and track near-Earth asteroids began”, according to Paul Chodas, manager of the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory in Pasadena, California. The close flyby was captured with an amateur astronomer using an 80 mm F5 Apo telescope and a Canon 6D camera, and published on youtube.

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Why do we see only one side of the Moon?

You have probably heard references been made to the “dark side” of the Moon – there’s even a Pink Floyd album with that name. But, in fact, there’s no “dark side” of the moon. Because it is not illuminated by the Earth, it is illuminated by the Sun. All the surface of the moon lit by the Sun as the Moon rotates. But, yes, we see only one side of the moon and here’s why.

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How Earth Could Die – 8 Horrible Ways

Now we’re living on a warm, hospitable planet. As Carl Sagan has said “That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.” We, humans, are the unquestionable rulers of our little oasis in a hostile universe. But all things must pass. The life on Earth, even the planet itself, won’t last forever. What’s more, the humans may go extinct before our planet (and probably before the life on it) dies out. Here some possible (and horrible) ways how planet Earth could die.

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Leaving Solar System at the Speed Of Light

Our Solar system is big, and vast, despite it is really small compared to our galaxy, not to mention the complete universe. To put this into a perspective, you can think yourself as a photon emitted by the Sun. It takes about 8 minutes to reach the Earth after a photon has been emitted from the Sun’s surface. And it takes 5 hours to get out to Pluto from the Earth. The edge of the Solar System is far beyond the orbit of Pluto.

But, where’s the edge of the Solar System? Well, It’s complicated. Informally, the term “solar system” is often used to mean the space out to the last planet – Neptune. Some scientists think that the solar system goes out to the Oort Cloud, the source of the comets. The inner edge of the main part of the Oort Cloud could be as close as 1,000 AU (Astronomical Unit, the distance between the Earth and the Sun, which is around 93 million miles or 150 million kilometers) from our sun. The outer edge is estimated to be around 100,000 AU.

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The Size Of Earth Compared to Other Planets and Stars (and the Universe)

When it comes to big numbers, very big numbers, the human brain is weak. In fact, our brains cannot deal with really large numbers. That’s why when the subject is Earth, planets, Solar System, galaxies, and in general, the Universe, we cannot truly conceptualize the things. A lot of people think we’re “conquering” space (we are far, far away from that – and maybe we never will), or the “aliens” are regularly visiting Earth as if it is just an hour’s drive from there. In fact, these people don’t truly understand what are they talking about, how big is the universe, how far the stars are, and how the Earth is a tiny, tiny spot in a vast space we are still striving to understand.

But we can try to understand and conceptualize. To put things into a perspective, YouTube user morn1415 prepared a video (he updated a previous video with the new findings in the astronomy).

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How Eratosthenes calculated the Earth’s circumference

In 240 BC, the Greek astronomer, geographer, mathematician, music theorist and librarian Eratosthenes of Cyrene (c. 276 BC – c. 195/194 BC) calculated the circumference of the Earth without even leaving Egypt. Here’s how:

Eratosthenes knew that at local noon on the summer solstice (at the time of the longest day, about 21 June in the northern hemisphere) in Syene (modern Aswan, Egypt), the Sun was directly overhead – Syene was in fact slightly north of the tropic, though (1). Local noon is – technically when the sub-solar point is somewhere over your meridian, it’s noon for you. So, on that day, Syene is the sub-solar point of Earth (the sub-solar point on a planet is where its sun is perceived to be directly overhead). To learn more about the local noon and the subsolar point, see the article titled “How Earth Moves“.

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