Joshy

I'm Josh and I'm from New Zealand. I like space and dogs.

[planned-planethood]

The South and North poles of Mars

(Image credit: ESA)

[planned-planethood]

I can’t believe I get to explore the north pole of mars with a nasa mission now, this post is so damn old! I still get notifications from this thing

This post was made a year after I decided this is what I wanted to do :)

[planned-planethood]

Might as well share a little bit of what I am up to…

This is the North Pole of Mars (no Santa, just martian Krampus):

(Image credit: USGS)

The section on the bottom that looks like a thumb curled to the left is called Gemina Lingula, and that is the region of the north polar layered deposits that I have been focusing on. Let’s zoom in:

(Image credit: NASA/JPL-Caltech/UArizona)

This is a close up image of what we call the “North Polar Layered Deposits”. This is basically just another word for the northern ice caps of Mars. It is thought that they hold the key to understanding how the climate has changed on Mars in the last few million years (yes, the climate changes on Mars too!).

What I do is I use radar data from NASA’s Mars Reconnaissance Orbiter mission (the SHARAD radar sounder specifically) to peer through the surface of the ice, revealing the subsurface world beneath:

(Image credit: NASA/JPL-Caltech/ASI/UT)

I work with radargrams like the one shown above, which is essentially a cross section that goes straight through the ice all the way to the bedrock at the bottom. You can see numerous places where there are reflections cutting from left to right in the ice. We know a lot of it is dust and ice, but there’s almost certainly a much greater story to tell here.

It’s quite difficult to actually piece together the story of Mars’ recent history (past 4 million years or so) by looking just at the radar data, but I believe that this, coupled with what we see exposed in the sides of the trough walls, may hold powerful clues as to what may have been happening there on the red planet not too long ago.

If we look in those troughs in the ice caps where we see stratigraphic layers (ancient ice caps from the martian past) exposed, we essentially get a tiny little window into what material might be encased in the ice. In order to begin pulling this story out of the light going back to the spacecraft, what I have been doing is using data from another MRO instrument called CRISM (which is a visible and infrared spectrometer) and performing what’s called principal component analysis on them. This essentially lets me create new versions of the image, where areas of high data variance are highlighted by specific colors. Usually, the most prominent variable is brightness, but that’s not what I’m looking for!

Here is an RGB (red, green, blue) image I made of the exposed stratigraphic layers, with the most interesting data variance being the red…

(Image credit: NASA, and myself)

This image is largely where I’ll leave you, because I can’t really talk too much about this yet for reasons but I will say, the fact that there’s a lot going on in the red parts of this image is promising: the red is exactly where the stratigraphic layers are, and you can even see that the red follows those layers. It’s really just more evidence that there’s a story here, Mars is showing us something, some sort of clue as to its recent past, and it’s so exciting to me to think that for whatever reason, this place is still so intimately tied to my life. Love ya Mars

[spacewonder19]

The Witch Head eyeing Rigel by Brian Maurer

[space-pics]

Visions of Jupiter by NASA Goddard Photo and Video

[theminimalisto]

[gusgrissom]

Ron McNair, Ph.D. during his first shuttle flight, STS-41-B, in February 1984. He was the second Black American to fly in space and the first astronaut to play a real instrument in orbit!

“Just for fun, I took up a director’s hat, dark glasses, and a name tag that said ‘Cecil B. McNair’ on it… And I had a sound-synchronization slate with my name as director, and would use it as a gag when it was time to shoot some of the [Cinema]-360 footage. I’d go down and get my hat and glasses, and start yelling commands, and go for the whole Hollywood bit. We took that footage during some very serious periods, but my job was to pull it off. I just had a little fun in the process!” –Dr. McNair, 1985

[sixpenceee]

Relative rotation rates of the planets                           

[ababeinthewoods]

Uranus spinning other way like:

[andromeda1023]

Why Are Mars’ Sunsets Blue?

Earth and Mars are a bit like mirror worlds. Mars is the Red Planet. Earth is the pale blue dot. Mars is a frigid desert. Earth is full of water and life. But there’s another curious difference. The sky on Mars is red, while its sunsets are blue.

The reason behind this is similar to why our sky is blue and our sunsets are red. The light from the Sun scatters based on what’s in the atmosphere. Sunlight comprises light of many different wavelengths, and molecules and dust particles only interact with specific waves. The scattering of light by these particles is key to the color that we see.

Mars’ atmosphere is very tenuous – its pressure is equivalent to about 1 percent of Earth’s. It is made of carbon dioxide and has a lot of dust. This fine dust tends to scatter red light so that the sky appears reddish, which lets the blue light through. On Earth, it is the other way around. Blue light bounces off air molecules giving our sky its characteristic hue.

At sunset light has a longer distance to travel within the atmosphere, so it scatters more. What is left is the color that we see. On Earth, we have a wider palette of reds, which is actually amplified by ash from volcanoes and dust from fires. On Mars, we get a cool blue hue.

Curiosity, Spirit, and Opportunity, the indefatigable robotic rovers we’ve sent to the Red Planet, have witnessed and recorded the curious phenomenon. Interestingly, Earth and Mars are the only two places in the Solar System that have sunsets that we can observe.

Mercury lacks an atmosphere so we would see the Sun disappear while the temperature goes from 427°C (801°F) to -173°C (-279°F), as we shift from day side to night side. It also has a very long day, rotating on itself every 58 and a bit days. But going to Venus would be even worse. The thick cloud cover and extremely dense atmosphere would stop the rays of the Sun from reaching us. And the high temperature and acid rain would easily melt our suits – and eventually our faces – off.

Maybe Titan could offer a rare sunset, occasionally, within its dense atmosphere. But for the time being, our Earthly sunset and videos of Martian ones are the best we can hope for.

https://www.iflscience.com/space/why-are-mars-sunsets-blue/?fbclid=IwAR05IIHt576L2J46XVMBLLaAI2EnSj5YsqdAsSNknUXmePAUYVJ_VDEPqa8

[space-pics]

The Sun from the Internation Space Station by NASA’s Marshall Space Flight Center

[startswithabang]

Which Galaxy Looks The Most Like Our Milky Way?

“We’re not a grand spiral galaxy, as we’re lacking extended outer arms. Nor are we similar to Andromeda, our nearest large neighbor, which lacks a central bar. While one-third of spiral galaxies have bars, ours is smaller than many, like NGC 1300’s. The outer arms are neither irregular nor tightly wound; we’re not “flocculent.” Additionally, the Milky Way possesses a small but significant central bulge.”

From within the Milky Way, there’s a whole lot we don’t know about what our galaxy would look like from the outside. But we’ve been able to determine a lot from looking at our galaxy, and we’ve looked at literally millions upon millions of galaxies in enough detail to see which ones do, and don’t, resemble our own.

Although it’s one you’ve never heard of before, you’ll want to remember UGC 12158 after reading this. It might be the closest Milky Way twin you’ll ever see.

[the-wolf-and-moon]

Crescent Pluto

[photos-of-space]

New image of Mars from the Mars Express

[the-wolf-and-moon]

Storm Swirls and Rings of Saturn

[surroundingw]

nagusch  -  Speed of light between EARTH and MOON

[photos-of-space]

Next stop…..Mars

[wonders-of-the-cosmos]

Neptune seen in 1989 by the space probe Voyager 2.

Image credit: NASA

[spacetimewithstuartgary]

ENCELADUS SHINES UP SATURN’S SUPER-REFLECTOR MOONS

Radar observations of Saturn’s moons, Mimas, Enceladus and Tethys, show that Enceladus is acting as a ‘snow-cannon,’ coating itself and its neighbours with fresh water-ice particles to make them dazzlingly reflective. The extreme radar brightness also points to the presence of ‘boomerang’ structures beneath the surface that boost the moons’ efficiency in returning the microwave signals to the spacecraft. The results will be presented at the EPSC-DPS Joint Meeting 2019 in Geneva by Dr. Alice Le Gall.

Dr. Le Gall and a team of researchers from France and the US have analysed 60 radar observations of Saturn’s inner moons, drawing from the full database of observations taken by the Cassini mission between 2004 and 2017. They found that previous reporting on these observations had underestimated the radar brightness by a factor of two.

Unprotected by any atmospheres, Saturn’s inner moons are bombarded by grains of various origins which alter their surface composition and texture. Cassini radar observations can help assess these effects by giving insights into the purity of the satellites’ water ice.

The extreme radar brightness is most likely related to the geysers that pump water from Enceladus’s internal ocean into the region in which the three moons orbit. Ultra-clean water ice particles fall back onto Enceladus itself and precipitate as snow on the other moons’ surfaces.

Dr. Le Gall, of LATMOS-UVSQ, Paris, explained: “The super-bright radar signals that we observe require a snow cover that is at least a few tens of centimetres thick. However, the composition alone cannot explain the extremely bright levels recorded. Radar waves can penetrate transparent ice down to few meters and therefore have more opportunities to bounce off buried structures. The sub-surfaces of Saturn’s inner moons must contain highly efficient retro-reflectors that preferentially backscatter radar waves towards their source.”

The nature of these scattering structures remains a mystery. Observations of Enceladus have shown a variety of surface and subsurface features, including ice-blocks, pinnacles, and dense collections of fractures in the surface caused by thermal stress or impacts. However, it has not been demonstrated that these would cause the extreme radar brightness observed at the moons.

More exotic structures, such as blade-like features called penitentes or bowl-shaped depressions in the snow known as sun cups, would provide the required reflective efficiency. However, it’s not clear that there is enough solar energy to sublimate the ice and form such structures.

Dr. Le Gall and colleagues have now developed a series of models to test whether specific shapes are acting as effective retro-reflectors or whether random scattering events caused by fractures in the surface are combining to enhance the reflection of the signal back towards the spacecraft.

“So far, we don’t have a definitive answer,” said Dr. Le Gall. “However, understanding these radar measurements better will give us a clearer picture of the evolution of these moons and their interaction with Saturn’s unique ring environment. This work could also be useful for future missions to land on the moons.”

IMAGE 1….The Saturnian system

IMAGE 2….Mosaic of the surface of Enceladus captured by Cassini on 9th October 2008 from an altitude of 25 kilometres. Image Credit: NASA/JPL/Space Science Institute

IMAGE 3….Saturn’s moon, Mimas showing dark regions below bright crater walls and streaks on some of the walls. NASA/JPL/Space Science Institute

IMAGE 4….Mosaic view of Saturn’s moon Tethys showing Odysseus crater. NASA/JPL/Space Science Institute

IMAGE 5….Boulder-strewn surface of Enceladus in context of a wide-angle camera image. Both images were acquired at an altitude of approximately 208 kilometers by the Cassini mission. NASA/JPL/Space Science Institute

IMAGE 6….Blade-like features called penitentes, here observed on the surface of Pluto, would provide the required reflective efficiency for the radar brightness seen at Mimas, Tethys and Enceladus. However, it’s not clear that there is enough solar energy to sublimate the ice and form such structures. Credit: NASA/JHUAPL/SwRI

[the-wolf-and-moon]

Northern Saturn