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Space Exploration Physics

Why do Astronauts Float in Space? [Microgravity Explained]

Why do astronauts float in space? Photo: Chris Hadfield, the ex-commander of the International Space Station while recording a revised cover version of David Bowie's famous song Space Oddity on board.
We see images and videos from the International Space Station (ISS) where astronauts float in space freely. Have you ever wondered why? Why do astronauts float in space? Photo: Chris Hadfield, the ex-commander of the International Space Station while recording a revised cover version of David Bowie's famous song "Space Oddity" on board.

We see images and videos from the International Space Station (ISS) where astronauts float in space freely. That’s because they’re in space, so there is no gravitational force of Earth there, right?

Wrong.

The International Space Station is in Low Earth Orbit (see notes 1) with an altitude of between 330 and 435 km (205 and 270 mi). It is so close to the Earth that on a clear day easily visible to the naked eye from the ground as it is the third brightest object in the sky (NASA has actually launched a new interactive map at its Spot the Station website).

At that altitude, the Earth’s gravity is about 90 percent of what it is on the planet’s surface – still pretty strong, right? To reduce the gravity of the Earth by a factor of one million, one needs to be at a distance of 6 million kilometers (around 3,728,227 miles) from the Earth – more than fifteen times the distance between the Earth and the Moon.

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Animals Life on Earth

Japanese Man Lives With Pet Caiman

Japanese man walks with caiman
Another unique and interesting friendship between a wild reptile and a man, like the famous story of Chito and Pocho. This Japanese man, named Nobumitsu Murabayashi, keeps a giant caiman as a pet, and even walks with him in the town center of Kure City, Hiroshima, Japan - with the permission of the city hall. Image: NTD Television

Another unique and interesting friendship between a wild reptile and a man, like the famous story of Chito and Pocho. This Japanese man, named Nobumitsu Murabayashi, keeps a giant caiman as a pet and even walks with his pet caiman in the town center of Kure City, Hiroshima, Japan – with the permission of the city hall.

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History Climate Places Solar System

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

Ruins of Göbekli Tepe
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.

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Astronomy Earth from Space Space Exploration

Earth Between the Rings of Saturn

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.

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Earth from Space Space Exploration

The Black Marble [Earth from Space at Night]

Earth from Space at Night (NASA)
Today (April 12, 2017), NASA scientists have just released the first new global map of Earth at night after the original Black Marble, as well as a revised version of the 2012 map. The new images were taken in 2016 and they provide researchers with a unique perspective of human activities around the globe. By studying Earth at night, researchers can investigate how cities expand, monitor light intensity to estimate energy use and economic activity, and aid in disaster response.

The first new global map of Earth from space at night since 2012 has been released by NASA scientists. The nighttime look of our planet is dubbed the “Black Marble”. But why?

On December 7, 1972, the crew of Apollo 17 spacecraft en route to the Moon 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“.

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, Harvard graduate student. Millions of people gather in the United States for the event.

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Earth from Space Planet Earth Space Exploration

Jeff’s Earth [Amazing HD Video from the ISS]

Red Sea from Space
On his most recent trip to the International Space Station (Expedition 48), recently-retired NASA astronaut Jeff Williams has recorded a great HD video of Earth using an Ultra High Definition video camera. In this amazingly beautiful image, we can see the Red Sea, Nile River, Suez Canal, and the southern Mediterranean.

On his most recent trip to the International Space Station (Expedition 48), recently-retired NASA astronaut Jeff Williams has recorded a great HD video of Earth (titled Jeff’s Earth) using an Ultra High Definition video camera.

Here in the video titled “Jeff’s Earth” below, he shares some of those images and talks about the beauty of the planet, the variety of things to see, and the value of sharing that perspective with everyone who can’t go to orbit in person.

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Astronomy

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

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 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.

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Life on Earth Astronomy

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

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).
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.

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Life on Earth Animals Climate Prehistoric

Here’s how the darkness and cold killed the dinosaurs 66 million years ago

Dinosaur extinction
Now we have a computer simulation of how the afterward effects of famous Chicxulub asteroid (estimated to be 10 km/6.2 mi) wide) killed the non-avian dinosaurs (and also a wide range of other species). On January 13, 2017, an article titled "Baby, it's cold outside: Climate model simulations of the effects of the asteroid impact at the end of the Cretaceous", published by the Climate scientists of Potsdam Institute for Climate Impact Research (PIK), revealed a detailed model of what happened to the atmosphere and the climate after the Chicxulub impact.

The catastrophic event that ended the reign of the dinosaurs 66 million years ago has been a subject of fascination and research for decades. A groundbreaking study by the Potsdam Institute for Climate Impact Research, detailed in their 2017 article “Baby, it’s cold outside: Climate model simulations of the effects of the asteroid impact at the end of the Cretaceous,” offers a compelling computer simulation of the aftermath of the Chicxulub asteroid impact.

This simulation reveals how prolonged darkness and severe cold, triggered by sulfuric acid droplets blocking sunlight, led to a dramatic global temperature drop and significant ecological shifts, ultimately contributing to the mass extinction of the non-avian dinosaurs and other species. This research not only illustrates the direct consequences of the asteroid impact but also provides insights into the complex climatic and environmental changes that followed, marking a pivotal moment in Earth’s history.

Chicxulub impact

Related: Dinosaur-killer asteroid hit the “worst possible place”, scientists say

Baby, It’s Cold Outside: How the Darkness and Cold Killed the Dinosaurs

Scientists created a computer simulation of how the afterward effects of the famous Chicxulub asteroid (estimated to be 10 km/6.2 miles wide) killed the non-avian dinosaurs (and also a wide range of other species). According to a new study, after the devastating impact, the darkness and cold killed the dinosaurs 66 million years ago.

On January 13, 2017, an article titled “Baby, it’s cold outside: Climate model simulations of the effects of the asteroid impact at the end of the Cretaceous”, published by the Climate Scientists of Potsdam Institute for Climate Impact Research (PIK), revealed a detailed model of what happened to the atmosphere and the climate after the Chicxulub impact.

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Earth from Space Climate Space Exploration

GOES-16 Satellite delivers breathtaking Earth Images

Earth and-Moon. GOES-16 image.
Launched on November 19, 2016 from Cape Canaveral Air Force Station, the satellite now known as GOES-16 can now observe planet Earth from a geostationary orbit 22,300 miles above the equator. Its Advanced Baseline Imager captured this contrasting view of Earth and a gibbous Moon on January 15. The stark and airless Moon is not really the focus of GOES-16, though. Capable of providing a high resolution full disk image of Earth every 15 minutes in 16 spectral channels, the new generation satellite's instrumentation is geared to provide sharper, more detailed views of Earth's dynamic weather systems and enable more accurate weather forecasting. Like previous GOES weather satellites, GOES-16 will use the moon over our fair planet as a calibration target. Image: NASA.gov

The first set of images from the GOES-16 satellite (see notes 1) have been released by the National Oceanic and Atmospheric Administration (N0AA). In the video below, published by Space.com, you can see the amazing images of the Earth and the Moon.

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