Category: Solar System

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Solar System Astronomy Life on Earth Planet Earth Prehistoric

What are the Differences Between a Meteoroid, a Meteor, a Meteorite, an Asteroid, and a Comet? [Explained]

Two asteroids passing Earth
Two Near-Earth Objects (in this case, two asteroids) passing Earth. An ESA image, published in the "Space in Images" series by the European Space Agency. A near-Earth object (NEO) is any small Solar System body whose orbit can bring it into proximity with Earth. By definition, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU, roughly the distance between the Earth and the Sun, which was defined exactly as 149,597,870,700 meters or about 150 million kilometers or 93 million miles since 2012). If a NEO's orbit crosses the Earth's and the object is larger than 140 meters (460 ft) across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids.

Hint: they are all space rocks. But, there are some differences. The biggest difference between an asteroid and a comet, for example, is what they are made of.

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Astronomy Solar System

Virtual Reality Tour of 6 Real Exoplanets [4K Ultra-HD, 360°]

Kepler-62e artist conception
Artist's conception of Kepler-62e, a super-Earth-size planet in the habitable zone of Kepler-62, a star smaller and cooler than the sun, located about 1,200 light-years from Earth. Image: Wikipedia

What would it be like to stand on the surface of another planet? “We The Curious” channel has teamed up with a group of astrophysicists to create a scientifically accurate virtual reality tour of six real exoplanets discovered outside our solar system. The fruit of this collaboration is the video below, in 4K Ultra-HD and 360-degree. Narrated and produced by Ross Exton.

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Astronomy Climate Physics Solar System Space Exploration

Want to Become a Citizen Scientist for NASA? Now you can

NASA identified an aurora-related celestial phenomenon STEVE with the help of citizen scientist program
STEVE (Strong Thermal Emission Velocity Enhancement) and the Milky Way at Childs Lake, Manitoba, Canada. The picture is a composite of 11 images stitched together. STEVE is short for Strong Thermal Emission Velocity Enhancement. It is a rare type of aurora, a thin purple ribbon of light. Scientists have now learned, despite its ordinary name, that STEVE may be an extraordinary puzzle piece in painting a better picture of how Earth's magnetic fields function and interact with charged particles in space. People were out observing the aurora and they started noticing something that was overhead as well, when they were seeing the aurora far to the northern regions. Liz MacDonald, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the leader of The Aurorasaurus team, says: "It was unlike most aurora. (They) talked to scientists, but we didn't know what it was. They said we'll keep taking observations and we call it STEVE in the meantime". "STEVE is mostly a very narrow purple arc and sometimes it has these little green features that go along with it as well that are kind of like waving fingers, or a picket fence. That means that there's plasma physics happening up there to cause that light, and to make these little discreet features that we don't understand yet." Image Courtesy: Krista Trinder. Image source: NASA Goddard Flight Center Photo Stream on Flickr

You can help NASA on some projects: for instance, citizen scientists helped NASA identify an aurora-related celestial phenomenon, now called STEVE. Want to become a citizen scientist? You can find projects on the NASA website.

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Solar System Planet Earth

The “Synestia Theory” says the Moon was formed 1,000 years earlier than Earth

A terrestrial synestia and formation of the Moon
Artist's conception of hot, molten Moon emerging from a terrestrial synestia, a giant spinning donut of vaporized rock that formed when planet-sized objects collided. Image by Sarah Stewart/UC Davis based on NASA rendering. According to a new study, the Moon might have been formed a thousand years earlier than Earth. The new, "synestia theory" suggests a Mars-sized object smashed into the proto-Earth. The "giant impact" vaporized about 10 percent of the rock and liquefied the rest, and created a rapidly spinning donut-shaped mass of vaporized rock called "synestia". The synestia eventually shrunk and cooled. Computer models demonstrated that the Earth subsequently emerged about 1,000 years after the moon.

According to a new study, the Moon might have been formed a thousand years earlier than Earth. The new “synestia theory” suggests a Mars-sized object smashed into the proto-Earth. The “giant impact” vaporized about 10 percent of the rock and liquefied the rest, and created a rapidly spinning donut-shaped mass of vaporized rock called “synestia”. The synestia eventually shrunk and cooled. Computer models demonstrated that the Earth subsequently emerged about 1,000 years after the moon.

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Astrobiology Solar System Space Exploration

We May Have Already Detected Signs of Alien Microbes on Saturn’s Moon Enceladus

Enceladus as viewed from NASA's Cassini spacecraft
Enceladus as viewed from NASA's Cassini spacecraft. It is Saturn's sixth-largest moon, only 157 miles (252 km) in mean radius, but it's one of the most scientifically compelling bodies in our solar system. Hydrothermal vents spew water vapor and ice particles from an underground ocean beneath the icy crust of Enceladus. This plume of material includes organic compounds, volatile gases, carbon dioxide, carbon monoxide, salts, and silica. With its global ocean, unique chemistry, and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist. Image: NASA.gov

According to a new study, microbes like those found in Earth’s deep ocean could potentially thrive in the underground ocean of Saturn’s icy moon Enceladus. Both molecular hydrogen (H2) and methane (CH4) already have been detected in the plume. Researchers have shown that Methanothermococcus okinawensis, a methanogenic archaeon first isolated from a deep-sea hydrothermal vent on the western Pacific Ocean, can produce methane under conditions known to exist on Enceladus.

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Space Exploration Solar System

Asteroid Mining: We Need Powerful Rockets like Falcon Heavy

Falcon Heavy Test Flight: Liftoff
Falcon Heavy Test Flight: Liftoff. When the rocket lifted off, it became the most powerful operational rocket in the world by a factor of two. This rocket that may one day carry humans to the Moon or Mars!

On February 6, 2018, SpaceX successfully tested Falcon Heavy, the most powerful rocket that the American company ever built. When lifted off, it became also the most powerful operational rocket in the world. Powerful rockets like Falcon Heavy may one day carry humans to the Moon or Mars. But there might be an even more important use of powerful rockets like SpaceX’ Falcon Heavy and BFR, Blue Origin’s New Glenn or NASA’s SLS: asteroid mining.

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Space Exploration Astronomy Earth from Space Solar System

OSIRIS-REx Captures New Earth-Moon Image from 39.5 Million Miles

Earth and Moon from 39.5 million miles. OSIRIS-REx image captured on January 17, 2018
NASA's asteroid-sampling OSIRIS-REx spacecraft captured a new Earth-Moon image on Jan. 17, 2018, from a distance of 39.5 million miles (63.6 million kilometers). Spacecraft used its NavCam1 imager to take this photo, as part of an engineering test. In the image, The Earth and the moon are just two bright dots against the vastness of black space - which reminds us Carl Sagan's famous speech: "That's here. That's home. That's us." 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. 101955 Bennu was discovered on September 11, 1999 by the Lincoln Near-Earth Asteroid Research (LINEAR) project, a collaboration of the United States Air Force, NASA, and the MIT's Lincoln Laboratory for the systematic detection and tracking of near-Earth objects. It is It is a potential Earth impactor. It has a 1-in-2,700 chance of impacting Earth in the late 22nd century. With a mean diameter of approximately 492 meters (1,614 ft; 0.306 mi), it can wipe out our civilization if it impact our planet. This is a cropped and resized image. You can see the original image on NASA web site.

NASA’s asteroid-sampling OSIRIS-REx spacecraft captured a new Earth-Moon image on Jan. 17, 2018, from a distance of 39.5 million miles (63.6 million kilometers). Spacecraft used its NavCam1 imager to take this photo, as part of an engineering test. In the image, The Earth and the moon are just two bright dots against the vastness of black space – which reminds us of Carl Sagan’s famous speech: “That’s here. That’s home. That’s us.”

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Space Exploration Earth from Space Solar System

New Horizons beats Voyager 1’s Record for being farthest from Earth while capturing images

New Horizons poster
Artist's conception depicting New Horizons spacecraft near Pluto. Pluto's moon Charon, also known as (134340) Pluto I is in the background. New Horizons is an interplanetary space probe that was launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institute (SwRI), with a team led by S. Alan Stern, the spacecraft was launched on January 19, 2006, from Cape Canaveral Air Force Station by an Atlas V rocket directly into an Earth-and-solar escape trajectory with a speed of about 16.26 kilometers per second (58,536 km/h; 36,373 mph). Its primary mission was to perform a flyby study of the Pluto system in 2015. It has a secondary mission to fly by and study one or more other Kuiper belt objects (KBOs) in the decade to follow. It is the fifth of five artificial objects to achieve the escape velocity that will allow them to leave the Solar System (others being Pioneer 10 - launched in 1972, Pioneer 11 - launched in 1973, Voyager 2 - launched in August 1977, and Voyager 1 - Launched in September 1977). Image: NASA Goddard Media Studios

It took 27 years, but finally, NASA’s New Horizons spacecraft beat Voyager 1‘s record for being farthest from Earth while capturing images. Taken on December 5, 2017, New Horizons’ image of the open star cluster NGC 3532 (also commonly known as the Football Cluster or the Wishing Well Cluster) became the farthest image ever made by any spacecraft, breaking a 27-year record set by Voyager 1. But for a very short time! About 2 hours later, New Horizons broke its own record with images of two Kuiper Belt objects.

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Astronomy History Solar System

Here’s why meteoroids explode before they reach Earth

Fireball created by the Chelyabinsk meteor. Why do meteoroids explode in the atmosphere?
The fireball created by the Chelyabinsk meteor. The light from the meteor was brighter than the Sun, visible up to 100 km (62 mi) away. It was observed over a wide area of the region and in neighboring republics. Some eyewitnesses also felt intense heat from the fireball. Due to its high velocity and shallow angle of atmospheric entry, the object exploded in an air burst over Chelyabinsk Oblast, at a height of around 29.7 km (18.5 mi; 97,000 ft). The explosion generated a bright flash, producing a hot cloud of dust and gas that penetrated to 26.2 km (16.3 mi), and many surviving small fragmentary meteorites, as well as a large shock wave. The bulk of the object's energy was absorbed by the atmosphere, with a total kinetic energy before atmospheric impact estimated from infrasound and seismic measurements to be equivalent to the blast yield of a nuclear weapon in the 400-500 kiloton (about 1.4-1.8 PJ) range - 26 to 33 times as much energy as that released from the atomic bomb detonated at Hiroshima. The object was undetected before its atmospheric entry, in part because its radiant was close to the Sun. Its explosion created panic among local residents, and about 1,500 people were injured seriously enough to seek medical treatment. All of the injuries were due to indirect effects rather than the meteor itself, mainly from broken glass from windows that were blown in when the shock wave arrived, minutes after the superbolide's flash. Some 7,200 buildings in six cities across the region were damaged by the explosion's shock wave, and authorities scrambled to help repair the structures in sub-freezing temperatures.

On 15 February 2013, an approximately 20-meter (66 feet) meteoroid (see notes 1) entered Earth’s atmosphere over Russia with a speed of 19.16 ± 0.15 kilometers per second (60,000-69,000 km/h or 40,000-42,900 mph). Its mass is estimated at 7,000 to 10,000 tons, one of the largest meteoroids that entered Earth’s atmosphere in recent history. Then, at 9:20 am local time (03:20 UTC), it exploded some 20 to 30 kilometers above the city of Chelyabinsk and created a gigantic fireball (known as a superbolide, see notes 1) brighter than the Sun.

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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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