Category Archives: Astronomy

Top 6 Biggest Stars in the Universe

What is the biggest star in the Universe? In fact, it is really hard to give an exact answer to this question since the universe is big, neighboring and the other galaxies are billions of light years away from us. But, we can give it a try. Here are the top 6 biggest stars in the Universe currently known by radius.

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Large Synoptic Survey Telescope will scan the skies for asteroids which threaten Earth

Around 66 million years ago, an asteroid (or a comet) with a diameter of at least 10 kilometers (6 miles) impacted a few miles from the present-day town of Chicxulub in Mexico at around 64,000 kilometers per hour (40,000 mph). The impact triggered a chain of events what it is known today as the Cretaceous-Paleogene (K-Pg) extinction event, also known as the Cretaceous-Tertiary (K-T) extinction, and wiped out three-quarters of the plant and animal species on Earth, including non-avian dinosaurs.

If this Chicxulub impactor happened today, it would wipe out the human civilization. Luckily, events like Chicxulub impact are rare. Asteroids with a 1 km (0.62 mi) diameter strike Earth every 500,000 years on average. But that doesn’t mean we are totally safe. Asteroids with a diameter of at least 140 meters (460 ft) are big enough to cause regional devastation to human settlements unprecedented in human history in the case of a land impact or a major tsunami in the case of an ocean impact.

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Watch: what other stars would look like in the place of the Sun

The Sun is the primary source of energy for Earth’s climate system, and the life on Earth. With a diameter of about 1.39 million kilometers (864,337 miles, i.e. 109 times that of Earth), and a mass about 1.9885×1030 kg (330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System), it may be the biggest thing in this neighborhood, but it is actually just a medium-sized star among the hundreds of billions of stars in the Milky Way galaxy. In the video published by the CAMENGAT creative astronomy below, you can see some dwarf stars and other giants compared to the Sun at the edge of its sphere: at 150 million kilometers (1 AUNotes 1) with a 50 mm objective. The stars are the Sun, Alpha Centauri A, Sirius, Vega, Pollux, Arcturus, Aldebaran, Rigel, Antares, and Betelgeuse. The scenario: Astronomical Observatory of Paranal, Chile.

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Song of Saturn and Its Moon Enceladus

NASA has published an amazing video titled “Sounds of Saturn: Hear Radio Emissions of the Planet and Its Moon Enceladus”. The analyze of the data from the Cassini Spacecraft’s Grand Finale orbits showed a surprisingly powerful interaction of plasma waves moving from Saturn to its icy moon Enceladus. Researchers converted the recording of plasma waves into a “whooshing” audio file that we can hear, in the same way a radio translates electromagnetic waves into music.

Much like air or water, plasma (the fourth state of matter) generates waves to carry energy. The recording was captured by the Radio Plasma Wave Science (RPWS) instrument on September 2, 2017, two weeks before Cassini was deliberately plunged into the atmosphere of Saturn.

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Hubble Space Telescope Launch

On April 24, 1990, Hubble Space Telescope was launched into low Earth orbit from space shuttle Discovery (STS-31). It orbits the Earth at an altitude of about 350 miles (560 kilometers). For a comparison, the International Space Station (ISS) maintains an orbit with an altitude of between 205 and 270 miles (330 and 435 kilometers). The telescope is 43.5 feet (13.2 meters) long, weighs 24,500 pounds (11,110 kilograms).

Here is a photo of the launch of the Hubble Space Telescope below.

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Moon Illusion: why the Moon looks larger when it’s near the horizon?

If you go out on a clear night when it’s the full moon, you may notice how gigantic the Earth’s satellite looks when it’s near the horizon. But, in fact, that moon is the exact same size as every other time as you’ve ever seen it in the sky. You can test this by holding your thumbnail at arm’s length and comparing it to the size of the Moon when it is near the horizon and high in the sky, and you’ll see it doesn’t change size. Photographs of the Moon at different elevations also show that its size remains the same. In fact, it plays a trick on your brain which called the “Moon Illusion”. This illusion has been known since ancient times, and an explanation of this optical phenomenon is still debated.

The moon illusion is subtle for some and dramatic for others (including me). A small fraction of people even don’t see it.

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How Far Away Is The Moon?

Yesterday, I stumbled upon a YouTube channel named The Science Asylum. In this channel, physicist Nick Lucid covers some popular science subjects. For example, the video below, titled “How Far Away Is The Moon?” explains the distance between the Earth and the moon, and how our brains aren’t good at dealing with the big numbers.

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