A Glory on Venus


Venus_glory_largeA rainbow-like feature known as a “glory” has been seen by ESA’s Venus Express orbiter in the atmosphere of our nearest planetary neighbor—the first time one has been fully imaged on another planet.

Rainbows and glories occur when sunlight shines on cloud droplets—water particles here on Earth. While rainbows arch across the sky, glories are typically much smaller and are made up of a series of coloured concentric rings centred on a bright core. Glories are only seen when the observer is situated directly between the Sun and the cloud particles that are reflecting sunlight. On Earth, they are often seen from aircraft, surrounding the shadow of the aircraft on the clouds below.

In order for a glory to occur, the particles must be spherical and the same size. The atmosphere of Venus is thought to contain droplets rich in sulphuric acid.

Mission scientists at ESA hoped to find a glory in the atmosphere of Venus by imaging the clouds with the Sun directly behind the Venus Express spacecraft. They were successful. The glory in this image was seen at the Venus cloud tops, 70 km above the planet’s surface. It is 1,200 km wide as seen from the spacecraft, 6,000 km away.

Image Credit: ESA

Venus in Infrared


Venus in IR_AkatsukiJAXA, the Japanese space agency, has a satellite orbiting Venus. Akatsuki took this photo of cloud patterns on the nightside of Venus from a distance of about 100,000 kilometers. The camera used sees at a wavelength of 2.26 microns, a wavelength at which the planet’s hot lower atmosphere radiates. This infrared light is blocked by clouds in some places but not others, silhouetting the clouds. Combining this data with data from other wavelengths and more images taken over time, Akatsuki scientists hope to watch the three-dimensional motion of Venus’ atmosphere.

Image Credit: JAXA

Five Planets


five_planets_chartFrom now until around Feb. 20, pre-dawn stargazers will stand a good chance of seeing all five planets known to ancient astronomers simultaneously: Mercury, Venus, Saturn, Mars and Jupiter. Those planets should be visible to the naked eye, but a pair of binoculars may be necessary to pull Mercury out of the pre-dawn sky glow from the Sun.

Jupiter will rise in the evening, then Mars will come over the horizon after midnight, followed by Saturn, then Venus, and Mercury just before dawn. All five should be visible from southeast to southwest between 6:00 and 6:30 am local time.

Image Credit: NASA

A Glory on Venus


Venus_glory_largeA rainbow-like feature known as a “glory” has been seen by ESA’s Venus Express orbiter in the atmosphere of our nearest planetary neighbor—the first time one has been fully imaged on another planet.

Rainbows and glories occur when sunlight shines on cloud droplets—water particles here on Earth. While rainbows arch across the sky, glories are typically much smaller and are made up of a series of coloured concentric rings centred on a bright core. Glories are only seen when the observer is situated directly between the Sun and the cloud particles that are reflecting sunlight. On Earth, they are often seen from aircraft, surrounding the shadow of the aircraft on the clouds below.

In order for a glory to occur, the particles must be spherical and the same size. The atmosphere of Venus is thought to contain droplets rich in sulphuric acid.

Mission scientists at ESA hoped to find a glory in the atmosphere of Venus by imaging the clouds with the Sun directly behind the Venus Express spacecraft. They were successful. The glory in this image was seen at the Venus cloud tops, 70 km above the planet’s surface. It is 1,200 km wide as seen from the spacecraft, 6,000 km away.

Image Credit: ESA

Venus in UV


Global_dynamics_of_Venus_northern_hemisphere_node_full_imageThis false-colour movie was put together using ultraviolet images taken by the Venus Monitoring Camera on board ESA’s Venus Express spacecraft on 22 May, 2006. The spacecraft was flying over the northern hemisphere at distances ranging between about 39,100 and 22,600 km from the surface.

Video Credit: ESA

An Eclipse


sunvenusuv3A rare solar eclipse occurred last year. Usually it’s the Moon that eclipses the Sun. Last year, the planet Venus took its turn. The black dot in the picture is Venus crossing in front of the Sun. In this case, the Sun was imaged in three colors of ultraviolet light by the Earth-orbiting Solar Dynamics Observatory.  The dark region on the right of the Sun’s face is a large coronal hole.

As I said, these eclipses are rare. The next Venusian solar eclipse will occur in 2117.

Image Credit: NASA

Triple Conjunction


tripleconjuntion2scaleWhile driving back home from Baltimore last night, my son and I saw a rare triple conjunction of the planets Mercury, Venus, and Jupiter in the early night sky. Last night’s show was the most compact arrangement of the planets, but they will be visible together all this week. Mercury and Venus will be a bit higher above the horizon at sunset each night even as Jupiter sinks lower. The picture on the left show the three planets to scale. Venus is the brightest object in the sky other than the Sun or Moon. It’s the planet nearest to Earth and, being closer to the Sun, brightly illuminated. Jupiter is the farthest of the three, but it’s large reflecting area makes up for the distance. Tiny Mercury is closest to the Sun, but reflects the least light to us of the three.

Image Credits: NASA

Morning Star


Venus was one of the morning stars last month. It has moved back into the glow of the Sun and will become an evening star in April. Here’s an unusual view of Venus as a morning star.Venus from Saturn 2

In this picture from NASA’s Cassini spacecraft dawn on Saturn is greeted by Venus. The inner planet appears just off the edge of Saturn in the upper right, directly above the white streak of Saturn’s G ring. Saturn’s E ring is also visible, looking blue because of the scattering properties of the dust that comprises the ring. The bright spot near the E ring is a distant star.

Another image of Venus and Saturn was taken when Cassini flew through the shadow of Saturn. This allowed the spacecraft to look back in the direction of the Sun and Venus and to take a backlit image of Saturn and its rings in a particular geometry which reveals details about the rings and Saturn’s atmosphere that cannot be seen at lower viewing angles. Venus can be seen through the rings.Venus from SaturnImage Credit: NASA

Venus’ First Closeup


Mariner10_Venus39 years ago today, Mariner 10 took this first close-up photo of Venus.

The original image was taken using an ultraviolet filter. This photo has been color-enhanced to show the planet’s cloudy atmosphere as the human eye would see it. Venus’ atmosphere is rich in carbon dioxide and is perpetually blanketed by a thick veil of clouds. Its surface temperature approaches 900 °F.

Mariner 10 flew by Venus in 1974.

Image Credit: NASA