SpaceTime 20180309 Series 21 Episode 19 Is Now Out

Stephen Hawking: a brief history of genius

London (AFP) March 14, 2018 Stephen Hawking, who has died aged 76, was Britain’s most famous modern day scientist, a genius who dedicated his life to unlocking the secrets of the Universe. Born on January 8, 1942 - 300 years to the day after the death of the father of modern science, Galileo Galilei - he believed science was his destiny. But fate also dealt Hawking a cruel hand. Most of his life was spent in Full article

Why doesn't Venus have a magnetosphere?

For many reasons, Venus is sometimes referred to as "Earth's twin" (or "sister planet," depending on who you ask). Like Earth, it is terrestrial (i.e. rocky) in nature, composed of silicate minerals and metals that are differentiated between an iron-nickel core and silicate mantle and crust. But when it comes to their respective atmospheres and magnetic fields, our two planets could not be more different.

Information on the lack of a Venusian magnetosphere

I’ve finally got round to continuing with my series of photos about the planets of the solar system! Next on my list is Venus. Venus is the second closest planet to our home star and notable for many strange oddities. For example, it has a rotational period of 243 days, whilst a year takes just 225 days. It has a diameter of ~12100km, making it very similar in size to Earth. It is often compared to Earth as its so-called twin planet, which may be true for aspects such as mass, size and proximity to the sun, but for almost everything else, they are vastly different.

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Hinode Views the 2012 Venus Transit

On June 5, 2012, Hinode captured these stunning views of the transit of Venus — the last instance of this rare phenomenon until 2117. Hinode is a joint JAXA/NASA mission to study the connections of the sun’s surface magnetism, primarily in and around sunspots.

Image credit: JAXA/NASA/Lockheed Martin

Pioneer Venus Artwork

Artist’s concept of Pioneer Venus mission approaching the planet.

During a 14-year orbit of Venus, Pioneer Venus 1 used radar to map the surface at a resolution of 75 km (47 miles). It found the planet to be generally smoother than Earth, though with a mountain higher than Mt. Everest and a chasm deeper than the Grand Canyon. The orbiter also found Venus to be more spherical than Earth, consistent with the planet’s much slower rotation rate (one Venus day equals 243 Earth days). It confirmed that Venus has little, if any, magnetic field and found the clouds to consist mainly of sulfuric acid. Measurements of this chemical’s decline in the atmosphere over the course of the mission suggested that the spacecraft arrived soon after a large volcanic eruption, which may also account for the prodigious lightning it observed.

After a course correction on 16 August 1978, Pioneer Venus 2 released the 1.5-m diameter large probe on 16 November 1978, at about 11.1 million km from the planet. Four days later, the bus released the three small probes while 9.3 million km from Venus. All five components reached the Venusian atmosphere on 9 December 1978, with the large probe entering first.

Data from the probes indicated that between 10 and 50 km, there is almost no convection in the Venusian atmosphere. Below a haze layer at 30 km, the atmosphere appears to be relatively clear. Amazingly, two of three probes survived the hard impact. The so-called Day Probe transmitted data from the surface for 67.5 minutes before succumbing to the high temperatures and power depletion.

Credit: NASA/Rick Guidice

Comparison of the planets of the solar system, Pluto and Sun in relation to the earth.

Images: commons.wikimedia (Sun: Alan Friedman)

Venus as seen from the Mariner 10 probe taken in 1974

(NASA)  Venus at Night in Infrared from Akatsuki

Image Credit: JAXA, ISAS, DARTS; Processing & Copyright: Damia Bouic

Why is Venus so different from Earth? To help find out, Japan launched the robotic Akatsuki spacecraft which entered orbit around Venus late in 2015 after an unplanned five-year adventure around the inner Solar System. Even though Akatsuki was past its original planned lifetime, the spacecraft and instruments were operating so well that much of its original mission was reinstated. Also known as the Venus Climate Orbiter, Akatsuki’s instruments investigated unknowns about Earth’s sister planet, including whether volcanoes are still active, whether lightning occurs in the dense atmosphere, and why wind speeds greatly exceed the planet’s rotation speed. In the featured image taken by Akatsuki’s IR2 camera, Venus’s night side shows a jagged-edged equatorial band of high dark clouds absorbing infrared light from hotter layers deeper in Venus’ atmosphere. The bright orange and black stripe on the upper right is a false digital artifact that covers part of the much brighter day side of Venus. Analyses of Akatsuki images and data has shown that Venus has equatorial jet similar to Earth’s jet stream.

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NASA theorizes a manned mission to Venus

Washington (UPI) Dec 19, 2014 The science world has been mostly fixated on Mars and comets, but some scientists at NASA are starting to talk about Venus - suggesting a manned mission to our closest neighbor could be simpler and less expensive than a trip to Mars. For some time, Mars has been the logical next step for the United States space program. It’s the closest planet with tolerable, Earth-like conditions. NAS Full article

A view of the Apollo 11 lunar module “Eagle” as it returned from the surface of the Moon to dock with the command module “Columbia”. A smooth mare area is visible on the Moon below and a half-illuminated Earth hangs over the horizon. The lunar module ascent stage was about 4 meters across. Command module pilot Michael Collins took this picture just before docking at 21:34:00 UT (5:34 p.m. EDT) 21 July 1969. (Apollo 11, AS11-44-6642)

Credit: Apollo 11, NASA