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

You wouldn’t be able to walk on Jupiter, Saturn, Uranus or Neptune because they have no solid surface!

The strength of the gravitational field of the body also plays a role: too weak a gravitational field rules out walking, in the sense of taking strides. We know what walking was like on the Moon. It was funny-looking, but definitely walking. But our Moon, with only 1/6 Earth’s surface gravity, has the strongest surface gravity among the other moons of the Solar System. (Our Moon is composed mostly of rock, while all the other moons are primarily ices, and therefore much less dense.) With a weaker gravity, walking would be even stranger, and slower, but at some point, nothing like steps could happen. Where to draw the line? What is meant by “walking”? With 1/10 of our Moon’s gravity, is it walking?

The surface gravity of a body depends on both its mass and on its radius: it is proportional to the mass divided by the square of the radius. Thus, a smaller body of denser material may have a higher surface gravity than one of lighter material.

On most asteroids and smaller moons, the gravity is just too low—it wouldn’t be walking. Some medium-sized moons may be border cases though.

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In space, no one can hear you scream. This is because there is no air in space – it is a vacuum. Sound waves cannot travel through a vacuum.

‘Outer space’ begins about 100 km above the Earth, where the shell of air around our planet disappears. With no air to scatter sunlight and produce a blue sky, space appears as a black blanket dotted with stars.

Space is usually regarded as being completely empty. But this is not true. The vast gaps between the stars and planets are filled with huge amounts of thinly spread gas and dust. Even the emptiest parts of space contain at least a few hundred atoms or molecules per cubic metre.

Space is also filled with many forms of radiation that are dangerous to astronauts. Much of this infrared and ultraviolet radiation comes from the Sun. High energy X-rays, gamma rays and cosmic rays – particles travelling close to the speed of light – arrive from distant star systems.

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The seventh planet from the Sun with the third largest diameter in our solar system, Uranus is very cold and windy. The ice giant is surrounded by 13 faint rings and 27 small moons as it rotates at a nearly 90-degree angle from the plane of its orbit. This unique tilt makes Uranus appear to spin on its side, orbiting the Sun like a rolling ball.

The first planet found with the aid of a telescope, Uranus was discovered in 1781 by astronomer William Herschel, although he originally thought it was either a comet or a star.

Uranus is one of two ice giants in the outer solar system (the other is Neptune). Most (80 percent or more) of the planet’s mass is made up of a hot dense fluid of “icy” materials—water, methane and ammonia—above a small rocky core. Near the core, it heats up to 9,000 degrees Fahrenheit (4,982 degrees Celsius).

Uranus is slightly larger in diameter than its neighbor Neptune, yet smaller in mass. It is the second least dense planet; Saturn is the least dense of all.

Uranus gets its blue-green color from methane gas in the atmosphere. Sunlight passes through the atmosphere and is reflected back out by Uranus’ cloud tops. Methane gas absorbs the red portion of the light, resulting in a blue-green color.

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There are dozens upon dozens of moons in the Solar System, ranging from airless worlds like Earth’s Moon to those with an atmosphere (most notably, Saturn’s Titan). Jupiter and Saturn have many moons each, and even Mars has a couple of small asteroid-like ones. But what about Venus, the planet that for a while, astronomers thought about as Earth’s twin? The answer is no moons at all. That’s right, Venus (and the planet Mercury) are the only two planets that don’t have a single natural moon orbiting them.

Because Mercury is so close to the Sun and its gravity, it wouldn’t be able to hold on to its own moon. Any moon would most likely crash into Mercury or maybe go into orbit around the Sun and eventually get pulled into it.

“Most likely, Venus was slammed early on and gained a moon from the resulting debris. The satellite slowly spiraled away from the planet, due to tidal interactions, much the way our Moon is still slowly creeping away from Earth,” Sky and Telescope wrote of the research.

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The term Blood Moon once was used in some sects of Christian prophecy to describe a total lunar eclipse that belonged to a tetrad of total lunar eclipses. The most recent Blood Moon – at least by this definition – took place on September 28, 2015. The next one won’t come until April 25, 2032.

The moon orbits around Earth, while Earth orbits around the sun. The moon takes about 27 days to orbit Earth and goes through regular phases in a 29.5-day cycle. The difference in these two cycles has to do with the relative positions of the sun, Earth and moon, which change during the moon’s orbit.

Lunar eclipses can only happen during a full moon, when the sun fully illuminates the surface. Usually a full moon has no eclipse because the moon orbits in a slightly different plane than the Earth and the sun do. However, at times the planes coincide. Earth passes in between the moon and the sun and cuts off the sunlight, causing an eclipse.

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Baade’s Window is an area of the sky with relatively low amounts of interstellar “dust” along the line of sight from the Earth. This area is considered an observational “window” as the normally obscured Galactic Center of the Milky Way is visible in this direction. It is named for astronomer Walter Baade who first recognized its significance. This area corresponds to one of the brightest visible patches of the Milky Way.

Walter Baade observed the stars in this area in the mid-1940s using the 100-inch (2.5 m) Hooker telescope at Mount Wilson Observatory in California while searching for the center of the Milky Way galaxy. Up until this time the structure and location of the galactic center was not known with certainty.

In 2006, the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS) conducted an astronomical survey to monitor 180,000 stars for seven days to detect extrasolar planets via the transit method.

Baade’s Window is frequently used to study distant central bulge stars in visible and near-visible wavelengths of light. Important information on the internal geometry of the Milky Way is still being refined by measurements made through this “window”. It is in the direction of the constellation of Sagittarius. The window is now known to be slightly “south” of the main central galaxy bulge. The window is irregular in outline and subtends about 1 degree of the sky. It is centered on the globular cluster NGC 6522.

Picture Credit : Google