Tupo Crater

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The Dawn spacecraft is still at Ceres and taking some great images. Interesting thing about the craters on Ceres, there are no ray structures accompanying them. There are a number of reasons this could occur, perhaps the gravitational field is such that the ejecta is blown clear of surface.

Here’s NASA’s description:
Tupo Crater, named for the Polynesian god of turmeric, is shown at upper left in this view of Ceres from NASA’s Dawn spacecraft. This impact feature is 22 miles (36 kilometers) in diameter and features a prominent central ridge of mountains.

Just below the crater, a line of narrow troughs parallels the rim of Tupo.

The image is centered at approximately 32 degrees south latitude, 90 degrees east longitude. Another view of Tupo is found at PIA20309.

Dawn acquired this image on Feb. 9, 2016, from its low-altitude mapping orbit, at a distance of about 240 miles (385 kilometers) from the surface. The image resolution is 120 feet (35 meters) per pixel.

image and description: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

April Skies

The month as opened with very nice skies, a bit cold in the mornings at -15 C. Despite the cold start April will feature at least a few (much) warmer conditions. I’m going to order a couple new of those reclining lawn chairs, and will enjoy the spring skies at a new location.

Video

NGC 2371 The One and Only

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Hubble shows NGC 2371 and 2372 is actually just one object, one very large nebula.

From ESA:
Stars of different masses end their lives in different ways. While truly massive stars go out in a blaze of glory, intermediate-mass stars — those between roughly one and eight times the mass of the Sun — are somewhat quieter, forming cosmic objects known as planetary nebulas.

Named because of their vague resemblance to planets when seen through early, low-resolution telescopes, planetary nebulas are created when a dying star flings off its outer layers of gas into space. This cloud forms an expanding shell around the central star, while the star itself slowly cools to become a white dwarf. This is what has happened in this NASA/ESA Hubble Space Telescope image, taken in 2007, which shows a planetary nebula known as NGC 2371.

NGC 2371 resides 4300 light-years away from us, in the constellation of Gemini. It is one of the largest planetary nebulas known, measuring roughly three light-years across. Its progenitor star can be seen here as a pinprick of orange–-red light, surrounded by a green, blue and aqua-tinged puff of gas. This shell appears to have a regular, elliptical shape that is sliced in half by a dark lane running through the nebula, which also encompasses the central star.

This dark feature misled astronomers when NGC 2371 was initially catalogued because the two lobes visually resembled two objects, not one. As a result of this confusion, the nebula has two names in William Herschel’s New General Catalogue: NGC 2371 and 2372 (often combined as NGC 2371/2 or NGC 2371-2).

Two prominent pink patches are also visible on either side of the central star. These features are thought to be knots of gas, most likely jets, thrown off by the star at some point in the past. Their pink colour indicates that they are cooler and denser than their surroundings.

The nebula’s central star was once similar to the Sun, but is now only a shadow of its former self. It is slowly cooling after energetically shedding most of its gas, but has a long way to go yet. It currently boasts a scorching surface temperature of over 130 000ºC – some 25 times hotter than the surface of the Sun – and glows with the luminosity of at least 700 Suns.

The hot ultraviolet radiation streaming outwards into the nebula energises the gas it touches, causing NGC 2371 to glow in the beautiful aquamarine colours seen in this image.

This picture was taken in November 2007 by Hubble’s Wide Field Planetary Camera 2. It is a false-colour image created with a combination of filters to detect light coming from sulphur and nitrogen (shown in red), hydrogen (green) and oxygen (blue). The observations were gathered as part of the Hubble Heritage project.

This image was originally published on the Hubble Space Telescope website on 4 March 2008.

Credit:  NASA/ESA/Hubble Heritage Team (STScI/AURA)

 

Martian Dust Devil

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The rover Opportunity looks back at its tracks leading up the north-facing slope of “Knudsen Ridge,” which forms part of the southern edge of “Marathon Valley” and saw the very well formed dust devil.  Click the image for a larger version.

Opportunity took the image using its navigation camera (Navcam) on March 31, 2016, during the 4,332nd Sol (Martian day).

Image: NASA/JPL-Caltech

 

Pluto in 3D

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Hopefully you have 3D glasses for this post.  This is an amazing image made as New Horizons encountered Pluto and shows some odd terrain.

If you don’t have glasses but do have access to some sort of clear red and blue plastic (or other material) you can try making your own,  Blue on the right and red on the left.

About the image from NASA and the New Horizons team:
One of the strangest landforms spotted by NASA’s New Horizons spacecraft when it flew past Pluto last July was the “bladed” terrain just east of Tombaugh Regio, the informal name given to Pluto’s large heart-shaped surface feature.

The blades are the dominant feature of a broad area informally named Tartarus Dorsa. They align from north to south, reach hundreds of feet high and are typically spaced a few miles apart. This remarkable landform, unlike any other seen in our solar system, is perched on a much broader set of rounded ridges that are separated by flat valley floors.

This amazing stereo view combines two images from the Ralph/Multispectral Visible Imaging Camera (MVIC) taken about 14 minutes apart on July 14, 2015. The first was taken when New Horizons was 16,000 miles (25,000 kilometers) away from Pluto, the second when the spacecraft was 10,000 miles (about 17,000 kilometers) away. Best resolution is approximately 1,000 feet (310 meters).

Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The Center of the Milky Way

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We are looking towards the center of our own galaxy.  The center is around 27,000 light-years away and an incredible number of stars can be seen in this wonderful Hubble image taken in the infrared.

This infrared image from the NASA/ESA Hubble Space Telescope shows the centre of the Milky Way, 27 000 light-years away from Earth. Using the infrared capabilities of Hubble, astronomers were able to peer through the dust which normally obscures the view of this interesting region. At the centre of this nuclear star cluster – and also in the centre of this image – the Milky Way’s supermassive black hole is located.

Read more about this Hubble image in Journey to the centre of our galaxy — ESA

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Raindrops

NASA and Japan Aerospace Exploration Agency Global Precipitation Measurement (GPM) mission are focusing on raindrops.

I will say if they looked at where I was yesterday they had plenty to look at with nearly four centimeters of rain in an hour streams were out of their banks.

Here’s the scoop from NASA:
“The drop size distribution is one of many factors that determines how big a storm will grow, how long it will last and how much rain it will ultimately produce,” said Joe Munchak, research meteorologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We’ve never been able to see how water droplet sizes vary globally until now.”

Storm clouds contain a wide variety of drop sizes that ultimately fall as rain or snow. In general, in the cores of clouds the drops tend to be bigger because they collide with each other and aggregate as they fall towards the Earth’s surface, while smaller droplets occur at the edges and higher altitudes. Drops tend to be small when they miss colliding into others or break apart. Scientists refer to the number of drops and snowflakes of different sizes at various locations within a cloud as the “particle size distribution.”

In order to accurately know how much precipitation is falling in a storm, scientists need to understand the ratio of large drops to smaller or medium sized drops. Previously, researchers had to make assumptions of the ratio because earlier studies were conducted in isolated locations and global data were limited, said Munchak.

“Without knowing the relationship or the ratio of those large drops to the smaller or medium sized drops, we can have a big error in how much rain we know fell and that can have some big implications for knowing long term accumulations which can help with flash flood predictions,” said Munchak.

“Without knowing the relationship or the ratio of those large drops to the smaller or medium sized drops, we can have a big error in how much rain we know fell and that can have some big implications for knowing long term accumulations which can help with flash flood predictions,” said Munchak.

With GPM’s three-dimensional snapshots of drop size distribution, scientists can also gain insight into the structure of a storm and how it will behave. Drop size distribution influences storm growth by changing the rate of evaporation of rain as it falls through dry air, said Munchak. Smaller drops, for instance, will tend to evaporate faster and subsequently cool the air more. This leads to stronger flow of downward moving air that can cause damaging winds when they reach the ground. However, these same downdrafts can interfere with the upward flowing air that fuels the storm and cause the storm to weaken or dissipate.

“GPM measurements will really help predict these complex interactions that depend in part of the drop size distribution,” said Munchak.

GPM was launched in 2014 and carries the first Dual-frequency Precipitation Radar (DPR) to fly in space, as well as a multi-channel GPM Microwave Imager (GMI). The DPR makes detailed 3D measurements of rainfall, while the GMI uses a set of 13 optimized frequencies to retrieve heavy, moderate, and light precipitation measurements at the Earth’s surface. As GPM improves our understanding of precipitation from space, that information will be vital in improving weather models and forecasts.

For more information on GPM, visit: http://www.nasa.gov/GPM

Hat tip to SpaceRef