Category The Universe, Exploring the Universe, Solar System, The Moon, Space, Space Travel

The ‘event horizon’ is the boundary defining the region of space around a black hole from which nothing (not even light) can escape. In other words, the escape velocity for an object within the event horizon exceeds the speed of light. The name arises since it is impossible to observe any event taking place inside it – it is a horizon beyond which we cannot see. 

When an item gets near an event horizon, a witness would see the item’s image redden and dim as gravity distorted light coming from that item. At the event horizon, this image would effectively fade to invisibility.

Within the event horizon, one would find the black hole’s singularity, where previous research suggests all of the object’s mass has collapsed to an infinitely dense extent. This means the fabric of space and time around the singularity has also curved to an infinite degree, so the laws of physics as we currently know them break down. 

The strength of a black hole’s gravitational pull depends on the distance from it — the closer you are, the more powerful the tug. But the effects of this gravity on a visitor would differ depending on the black hole’s mass. If you fell toward a relatively small black hole a few times the mass of the sun, for example, you would get pulled apart and stretched out in a process known as spaghettification, dying well before you reached the event horizon. 

 

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Astronomers have defined a new class of celestial objects called “ploonets,” which are orphaned moons that have escaped the bonds of their planetary parents.

Although there has yet to be a definitive detection of a ploonet orbiting a star, there are at least a few examples that might fit the bill. The evidence for these potential ploonets comes from perplexing exoplanetary observations that have yet to be adequately explained.

For instance, the researchers of the new paper describe how “moon-star collisions could explain the anomalous spectroscopic features of the stars Kronos and Krios (HD 240430 and HD 240429), which show deep traces of heavy elements.” This is because ploonets are likely made up of largely volatile material — which are light elements and compounds like hydrogen and water that rapidly evaporate — and because ploonets are located so close to their host stars, which exposes them to very strong stellar radiation.

According to the authors, this means that over millions of years, a ploonet will lose a significant chunk of its lighter elements, leaving behind a rather heavy-metal ploonet. If these metal-rich ploonets are then absorbed into their host star, they can produce observational signals that suggest the star instead devoured rocky planets, as may be the case with Kronos.

 

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A subsatellite is a natural or artificial satellite that orbits a natural satellite, i.e. a “moon of a moon”.

It is inferred from the empirical study of natural satellites in the Solar System that subsatellites may be elements of planetary systems. In the Solar System, the giant planets have large collections of natural satellites. The majority of detected exoplanets are giant planets; at least one, Kepler-1625b, may have a very large exomoon, named Kepler-1625b I. Nonetheless, no “moon of a moon” or subsatellite is known in the Solar System or beyond. In most cases, the tidal effects of the planet would make such a system unstable.

Terms used in scientific literature for moons of moons include “submoons” and “moon-moons”. Other terms that have been suggested include moonitos, moonettes, and moooons.

 

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Hayabusa 2 is a Japanese mission launched in December 2014 on a six-year mission to study the asteroid Ryugu and to collect samples to bring to Earth for analysis.

Hayabusa 2 was launched in December 3, 2014. The mission includes a main spacecraft, small rovers, a lander, and an impactor that will be launched into the asteroid’s surface to create an artificial crater. The spacecraft is expected to touch down on Ryugu multiple times starting in early 2019 to collect samples to bring to Earth in late 2020.

After launch, the spacecraft completed an initial checkout period by March 2, 2015 and then moved into its “cruising phase” toward asteroid Ryugu.

Less than a year later, on December 3, 2015, Hayabusa 2 carried out an Earth flyby at a range of 1,920 miles (3,090 kilometers) over Hawaii to increase the spacecraft’s velocity.

The spacecraft performed the first major firing of its ion engines between March 22 and May 5, 2016. It conducted a shorter (3.5 hour) firing on May 20, 2016 to adjust its trajectory.

Hayabusa 2 arrived at asteroid Ryugu in June 2018.

 

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The Dragon spacecraft first reached the International Space Station in 2012 and Crew Dragon became the first private, crewed spacecraft to reach the ISS in 2020.

In March 2019, SpaceX’s Crew Dragon, the company’s spacecraft designed to carry astronauts into space, completed its first test mission to the International Space Station (ISS). Prior to that, in 2012, the Dragon cargo spacecraft made history when it was the first private spacecraft to berth with the ISS. Since then, Dragon has continued carrying cargo to the ISS under commercial agreements with NASA. 

SpaceX successfully launched the Crew Dragon capsule to the ISS on March 2, 2019 from a two-stage Falcon 9 rocket. The spacecraft then docked with the ISS on March 3, and returned to Earth on March 8. 

SpaceX unveiled its design for the crewed spacecraft in 2014 to great fanfare. It’s essentially a modified version of SpaceX’s robotic Dragon spacecraft. Crew Dragon can carry up to seven astronauts, includes a life support system, an emergency-escape system, touch-screen displays, windows and other passenger-related equipment. Another design change is that Crew Dragon docks directly to the ISS while the Dragon freighter is grabbed by the orbiting lab’s large robotic arm and brought into place. 

 

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A new era in space flight began on April 12, 1981, when Space Shuttle Columbia, or STS-1, soared into orbit from NASA’s Kennedy Space Center in Florida.

Astronaut John Young, a veteran of four previous spaceflights including a walk on the moon in 1972, commanded the mission. Navy test pilot Bob Crippen piloted the mission and would go on to command three future shuttle missions. The shuttle was humankind’s first re-usable spacecraft. The orbiter would launch like a rocket and land like a plane. The two solid rocket boosters that helped push them into space would also be re-used, after being recovered in the ocean. Only the massive external fuel tank would burn up as it fell back to Earth. It was all known as the Space Transportation System.

Columbia accelerated into space propelled by two boosters that fell into the Atlantic Ocean, where they were later recovered and reused for other flights. The external tank fell from Columbia after about 9 minutes, and burned up in Earth’s atmosphere. The spacecraft was the first crewed American craft to fly without a prior uncrewed test flight, and was the first crewed mission to use solid fuel rockets.

Some of Columbia’s notable missions in later years included recovering the Long Duration Exposure Facility satellite from space (STS-32, January 1990), running the first Spacelab mission devoted to human medical research (STS-40, June 1991), and launching the Chandra X-Ray Observatory (STS-93, July 1999).

 

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