Category: Solar System

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Astronomy History Solar System

A new star in heavens: how Crab Nebula was born

Crab Nebula (ESO image)
This photo shows a three color composite of the well-known Crab Nebula (also known as Messier 1), as observed with the FORS2 instrument in imaging mode in the morning of November 10, 1999. It is the remnant of a supernova explosion at a distance of about 6,000 light-years. Japanese and Chinese astronomers recorded this violent event nearly 1,000 years ago in 1054, as did, almost certainly, Native Americans. It contains a neutron star near its center that spins 30 times per second around its axis. In this picture, the green light is predominantly produced by hydrogen emission from material ejected by the star that exploded. The blue light is predominantly emitted by very high-energy ("relativistic") electrons that spiral in a large-scale magnetic field (so-called synchrotron emission). It is believed that these electrons are continuously accelerated and ejected by the rapidly spinning neutron star at the centre of the nebula and which is the remnant core of the exploded star. This pulsar has been identified with the lower/right of the two close stars near the geometric center of the nebula, immediately left of the small arc-like feature, best seen in ESO Press Photo eso9948. Technical information: ESO Press Photo eso9948 is based on a composite of three images taken through three different optical filters: B (429 nm; FWHM 88 nm; 5 min; here rendered as blue), R (657 nm; FWHM 150 nm; 1 min; green) and S II (673 nm; FWHM 6 nm; 5 min; red) during periods of 0.65 arcsec (R, S II) and 0.80 (B) seeing, respectively. The field shown measures 6.8 x 6.8 arcminutes and the images were recorded in frames of 2048 x 2048 pixels, each measuring 0.2 arcseconds. North is up; East is left. Image: ESO

This is how the Crab Nebula was born: in 1054 A.D, a new, very bright star has appeared in Earth’s sky, in the constellation Taurus. Chinese, Japanese, Korean, and Arab astronomers observed the event and noted: “a new bright star emerged in the heavens”. The star was so bright: for nearly three weeks, it was visible even during the daytime, under the hot, shiny summer sun, and remained visible for around two years (653 days to be exact). Today, we know that that “heavenly star” was actually a supernova (SN 1054, see notes 1), and its remnant is what we now know as the Crab Nebula today (catalog designations M1, NGC 1952, Taurus A).

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Earth from Space Astronomy Solar System Space Exploration

Earth and Moon in the same photo

Earth and Moon as seen by OSIRIS-REx. October 2, 2017.
Earth and Moon as seen by OSIRIS-REx. October 2, 2017. The purpose of OSIRIS-REx spacecraft (acronym for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is to study, map and return samples for detailed analysis from asteroid 101955 Bennu, a carbon-rich hunk of rock that might contain organic materials or molecular precursors to life. It was launched on September 8, 2016, and expected return date is September 24, 2023. If successful, OSIRIS-REx will be the first NASA spacecraft to return samples from an asteroid.

An amazing image showing both the Earth and Moon. The distance between our planet and its satellite is actually much more than many would conceptualize. It is 384,400 kilometers (about 239,000 miles) on average, but as usual, our brains cannot deal with such large numbers. Only seeing that distance makes us realize how far even the closest body in the solar system to us – and gives some clues about how big is our Solar system actually. What’s more, we’ve actually been there, humanity managed to cover that vast distance and walked on the moon!

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Space Exploration Solar System

Voyager 1 Fired Up its Thrusters for the first Time in 37 Years

Voyager 1 in Deep Space (Artist Conception)
Voyager 1 in Deep Space (Artist's Conception). Since the Voyager spacecraft are identical, it could be Voyager 2, as well. The Voyager spacecraft were built by JPL, which continues to operate both. JPL is a division of Caltech in Pasadena. California. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington. Image: NASA.gov

On Tuesday, November 28, 2017, a set of thrusters aboard the Voyager 1 spacecraft successfully fired up for the first time since November 1980, after 37 years without use.

Voyager 1 is a space probe launched by NASA on September 5, 1977. Having operated for more than 40 years as of December 4, 2017, the spacecraft still communicates with the Deep Space Network to receive routine commands and return data. At a distance of 141 AU (see notes 1) (2.11×1010 km) or approximately 13 billion miles (21 billion km) from the Sun as of November 22, 2017, it is NASA’s farthest and fastest spacecraft. It is also the only human-made object in interstellar space, within the environment between the stars.

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Solar System Astronomy

What is a Supermoon and when is the next one?

Supermoon
The supermoon over the Dutch Caribbean, 50 miles north of Venezuela, November 15, 2016. Image: Betty Wills The Moon follows an elliptic orbit around Earth. Naturally, sometimes it gets closer to the Earth than the other times. When it's also full moon at its closest point to the Earth, it's called Supermoon. As a result, the moon appears larger and brighter than usual in the sky.

The Moon follows an elliptic orbit around Earth. Naturally, sometimes it gets closer to the Earth than the other times. When it’s also full moon at its closest point to the Earth, it’s called Supermoon. As a result, the moon appears larger and brighter than usual in the sky.

The counterpart of a supermoon is called Micromoon. A Supermoon looks around 12% to 14% bigger (in diameter) than the Micromoon.

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Astrobiology Astronomy Life on Earth Solar System Space Exploration

How to tell if a planet harbors life?

Earth from the Geostationary Orbit
Earth image taken by Japanese weather satellite Himawari 8, which takes a photo of Earth every 10 minutes. Himawari 8 is the 8th of the Himawari geostationary weather satellites operated by the Japan Meteorological Agency. Himawari 8 entered operational service on 7 July 2015 and is the successor to MTSAT-2 (Himawari 7) which was launched in 2006.

Are we alone in the universe? Or are there any other “living planets” other than Earth? How to tell if a planet harbors life? Until 1992, we even don’t know if there are any other planets around the other stars or not. In 1992, two Swiss astrophysicists, Michel Mayor and Didier Queloz the first “exoplanet” (a planet orbiting another star than the Sun).

Then, discoveries continued. Especially after the launch of the Kepler space telescope on March 7, 2009, which is a space observatory launched by NASA to discover Earth-size planets orbiting other stars, we quickly learned that our Solar System is not a rare phenomenon at all. As of November 2017, scientists have confirmed more than 3,500 exoplanets in more than 2,700 star systems. Now, the question is: are any of these planets (or the planets waiting to be discovered in the future) harbor life? If so, how we can find out?

Currently, we have only one example: the Earth itself. Studying Earth and trying to figure out how we’d conclude the Earth harbors life from a distance (from space) can show us how to find out if a planet harbors life or not. Since 1997, NASA satellites have continuously observed all plant life at the surface of the land and ocean.

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Space Exploration Astronomy Mars Solar System

Living on Mars is a terrible idea [we should colonize Titan, instead, scientist says]

Saturn viewed through Titan's hazy atmosphere
Artist's rendition of Saturn viewed through Titan's hazy atmosphere. Image: European Space Agency (ESA), Space in Images series. With a radius of 2575.5±2.0 km, Titan is the largest moon of Saturn. It is slightly bigger than our Moon (around 1.4 times - the radius of Moon is 1737 km or 1079 miles). It is the only moon in the Solar System known to have a dense atmosphere. And, even more important, it is the only object in Solar System (and even in space, so far) other than Earth where clear evidence of stable bodies of surface liquid has been found.

In September 2017, Elon Musk, the founder and CEO of SpaceX has revealed a new plan to colonize Moon and Mars with giant reusable spaceships. They are ambitiously planning to send the first humans to Mars as early as 2024 to build the foundations for the first Martian city. But is Mars really the best place for humans to settle? Some scientists, like Amanda Hendrix (see notes 1), the American planetary scientist, think it’s not, and we should be looking somewhere else and colonize Titan, Saturn’s largest moon, instead.

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Earth from Space Solar System Space Exploration

10 Most Iconic Photos of Earth from Space

The Blue Marble
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.

Earth is actually a fragile and isolated rock, a “blue marble” in a vast, cold, and hostile space. But only after seeing our planet from space, we did really understand that. Seeing the Earth first time from a distance was a powerful experience that has changed the way we see our planet. Here are the top 10 most iconic photos of Earth from space.

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Mars Science Fiction Solar System Space Exploration

Making Life Multiplanetary [Musk reveals a new plan to colonize Mars]

SpaceX Mars base
The billionaire founder of SpaceX, Elon Musk has revealed a new plan to colonize Moon and Mars with giant reusable spaceships. He provided an update on their Mars colonization plan at the International Astronautical Congress (IAC)Notes 1 in Adelaide, Australia this week. Musk plans sending 1 million people to Mars using BFRNotes 2, and "making life multiplanetary". He has highly ambitious plans like launching and landing at least two uncrewed cargo ships on Mars as early as 2022.

The billionaire founder of SpaceX, Elon Musk has revealed a new plan to colonize Moon and Mars with giant reusable spaceships. He provided an update on their Mars colonization plan at the International Astronautical Congress (IAC, see notes 1) in Adelaide, Australia this week. Musk plans to send 1 million people to Mars using BFR (see notes 2), and “making life multiplanetary”. He has highly ambitious plans, like launching and landing at least two uncrewed cargo ships on Mars as early as 2022.

The newly announced BFR is smaller than the one Musk revealed at the same event last year, 106 meters (348 feet) tall and carrying capacity of 150 tonnes compared to the previous design’s 122 meters (400 feet) and 300 tonnes. But, (naturally) it’s way cheaper than the previously announced version, and according to Musk, “lower cost is the biggest update”. And, still, it is more powerful than any of SpaceX’s or NASA’s other planned rockets.

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Space Exploration Astronomy Solar System

20 Best Photos of Cassini’s voyage around Saturn

Saturn by Gordan Ugarkovic
This view of Saturn was created made by the amateur image processor and Cassini fan Gordan Ugarkovic from images obtained on October 10, 2013. It was chosen as NASA's image of the day for October 17, 2013. You can see the full-resolution image on NASA's web site.

Launched on October 15, 1997, NASA’s Cassini spacecraft (see 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 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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Solar System Astronomy

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

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.

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