Category: Astronomy

When stars will be passing close to the Sun? Now we know

Post author By M. Özgür Nevres
Post date September 9, 2017
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Scholz'z Star — Artist's conception of Scholz's star and its brown dwarf companion during its flyby of the solar system 70,000 years ago. The Sun (left, background) would have appeared as a bright star. The pair is now about 20 light years away from the Sun. Image Credit: Michael Osadciw/University of Rochester.

Sometimes, a wondering star comes and passes so close to our Sun. Now, thanks to data provided by the Gaia spacecraft, we can know the occurrence of these close passing-bys in advance.

This potentially dangerous event last happened about 70,000 years ago, a wandering binary stellar system passed through the Solar System‘s Oort cloud (see notes 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 leave Africa at that time. The binary system is dubbed as Scholz’s Star (see notes 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.

Total Solar Eclipse 2017 Images From Space [plus videos]

Post author By M. Özgür Nevres
Post date September 6, 2017
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2017 Total Solar Eclipse from the ISS — 2017 Total Solar Eclipse as seen from the International Space Station. Only six people saw the event from the Space: NASA's Randy Bresnik, Jack Fischer and Peggy Whitson, ESA (European Space Agency's) Paolo Nespoli, and Roscosmos' Commander Fyodor Yurchikhin and Sergey Ryazanskiy. This photo is published by Paolo Nespoli on his twitter account. I switched the photo upside down 180-degree for a better view.

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.

Astronomy

TRAPPIST-1 System May Contain Water

Post author By M. Özgür Nevres
Post date September 2, 2017
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Possible surface of TRAPPIST-1f — This illustration shows the possible surface of TRAPPIST-1f, one of the newly discovered planets in the TRAPPIST-1 system. Scientists using the Spitzer Space Telescope and ground-based telescopes have discovered that there are seven Earth-size planets in the system. Credits: NASA/JPL-Caltech

On February 22, 2017, NASA astronomers have announced that seven Earth-sized planets have been discovered around an ultra-cool dwarf star named TRAPPIST-1 which is located around 39 light-years from the Earth. And what’s more – three of them are orbiting their star in the habitable zone. Now scientists find clues that TRAPPIST-1 system may contain water.

Then, an international team of astronomers led by the Swiss astronomer Vincent Bourrier from the Observatoire de l’ Université de Genève used the NASA/ESA Hubble Space Telescope to estimate whether there might be water on the planets of TRAPPIST-1 system.

Now, on August 31, 2017, the team announced that their findings suggest that “the outer planets of the system might still harbor substantial amounts of water”, including the three planets within the habitable zone of the star – TRAPPIST-1e, f, and g. This result lends further weight to the possibility that these planets may indeed be habitable.

Solar System Astronomy

Huge Asteroid “3122 Florence” flyby video

Post author By M. Özgür Nevres
Post date September 2, 2017
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Asteroid 3122 Florence flyby illustration — A scaled illustration of the flyby of 3122 Florence. On September 1, 2017, it skimmed past Earth from a mere 4.4 million miles (7 million km) distance - which is about 20 times the distance between Earth and Moon. Image: NASA 3122 Florence was discovered on 2 March 1981 by American astronomer Schelte J. "Bobby" Bus at Siding Spring Observatory. It was named in honor of Florence Nightingale (12 May 1820 - 13 August 1910), the English social reformer and statistician, and the founder of modern nursing. It is classified as a near-Earth object (NEO)⁽¹⁾ and potentially hazardous object (PHO)⁽²⁾. It is really big that if it would the Earth, it could cause a major extinction event. It is almost as big as the Chicxulub asteroid which hit the Earth 66 million years ago, also known as the "dinosaur killer". The September 2017 encounter of 3122 Florence was the closest by this asteroid since 1890 and will remain the closest it will ever be until after 2500.

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.

Planet Earth Astronomy

What would happen if the Earth stopped rotating?

Post author By M. Özgür Nevres
Post date August 10, 2017
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In December 1972, Apollo 17 spacecraft took a photo of Earth from space, at a distance of about 45,000 kilometers (28,000 miles). This image, with the official NASA designation AS17-148-22727, became known as "The Blue Marble", one of the most iconic photos of Earth from space. In fact, it was not the first clear image of Earth taken from space - similar photos had already been taken as early as 1967. But, the 1970s were the scene of a big surge in environmental activism. For example, on April 22, 1970, the first "Earth Day" was organized by Gaylord Nelson, former senator of Wisconsin, and Denis Hayes, a Harvard graduate student. Millions of people gather in the United States for the event. So, in today's terms, image AS17-148-22727 went "viral" and became a symbol of the environmental movement, as a depiction of Earth's frailty, vulnerability, and isolation amid the vast expanse of space. According to NASA archivist Mike Gentry, it is among the most widely distributed images in human history.

The Earth rotates from west to east with a linear velocity of 465.1013 m/s (1674.365 km/h) at the equator. But what would happen if the Earth stopped rotating abruptly? Online magazine Tech Insider presented a video demonstrating the development of events in this case.

Solar System Astronomy Physics Planet Earth

Here’s why we see only one side of the Moon [Tidal locking explained]

Post author By M. Özgür Nevres
Post date August 3, 2017
2 Comments on Here’s why we see only one side of the Moon [Tidal locking explained]

Why do we see only one side of the moon: Moon in the sky over trees — You have probably heard references 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, we always see the "same side" of the moon from the Earth. Photo: pexels.com

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

History Climate Places Solar System

Ancient Carvings in Göbekli Tepe Show a Comet hit Earth 13,000 Years Ago

Post author By M. Özgür Nevres
Post date April 24, 2017
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Ruins of Göbekli Tepe, Turkey. Photo by Teomancimit - Own work, CC BY-SA 3.0, Link

Ancient symbols carved into stone at Göbekli Tepe (an archaeological site in Turkey) tell the story of a big comet impact more than 13,000 years ago, scientists think. The devastating impact triggered a mini ice age that drove many mammals weighing more than 40 kg to extinction.

According to an article published by New Scientist, carvings made on a pillar known as the “Vulture Stone” in Göbekli Tepe suggest that a swarm of comet fragments hit the Earth in around 11000 BC.

Astronomy Earth from Space Space Exploration

Earth Between the Rings of Saturn

Post author By M. Özgür Nevres
Post date April 22, 2017
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Earth between Saturn'a Rings NASA image — NASA's Cassini spacecraft captured this view of planet Earth as a point of light between the icy rings of Saturn on April 12, 2017.

A beautiful image published by NASA, taken by the uncrewed Cassini-Huygens spacecraft, shows the Earth between the rings of Saturn. The image was taken on April 12, 2017.

Astronomy

7 Earth-Sized Planets Found Orbiting Nearby Star TRAPPIST-1 [3 of them are in the Habitable Zone!]

Post author By M. Özgür Nevres
Post date February 23, 2017
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On February 22, 2017, NASA has announced that seven Earth-sized planets have been observed by NASA’s Spitzer Space Telescope around TRAPPIST-1, a tiny, nearby, an ultra-cool dwarf star located 39 light-years (12 parsecs; 370 petametres) away from Earth in the constellation Aquarius. The good news is: three of these planets are firmly in the habitable zone. The new discovery may be a great breakthrough in the search for extraterrestrial life.

Life on Earth Astronomy

51 Pegasi b: The First Exoplanet to be Discovered Orbiting a Sun-Like Star

Post author By M. Özgür Nevres
Post date February 4, 2017
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Artist's impression of the exoplanet 51 Pegasi b, the first the first exoplanet to be discovered orbiting a main-sequence star (a sun-like star).

51 Pegasi b, discovered in 1995, marked a pivotal moment in astronomy, being the first exoplanet confirmed to orbit a Sun-like star. Located approximately 50 light-years away in the constellation Pegasus, this gas giant revolutionized our understanding of planetary systems. Unlike the gas giants in our solar system, 51 Pegasi b orbits remarkably close to its star, completing a full orbit in just over 4 days. This proximity results in extreme temperatures, making it a ‘hot Jupiter’. Its discovery, led by Michel Mayor and Didier Queloz, challenged existing theories about planet formation and prompted a reevaluation of our place in the cosmos.