Archive for April, 2009

Kepler Mission – Mr. Ian Bradley you have an answer

A question made by Ian Bradley arrived my e-mail via Stuart Atkinson, since there might be other Kepler fans with the same doubt I decided to bring it here:

Regarding the Kepler 1st light image…
 
The imaged area is well away from the ecliptic to allow 24/7 viewing of the image area without Sun being a problem. On a quick glance at the high res 23Mb image from the Kepler website, there are several diagonal tracks [not the vertical or horizontal blooming from bright stars]. One is particularly bright (see below for position). Are these earth orbit satellites (given that Kepler is in an Earth trailing heliocentric orbit, this seems unlikely) or are they other solar system bodies e.g. minor planets, asteroids, Keuper Belt objects etc, etc. I guess it could be crap from the spacecraft itself…
 
Clearly they cannot be in the ecliptic! Few surveys have been done at large angles away from the ecliptic, so have we got a way to discover other members of the Solar System? 
 
Bright diagonal object position – treat ccd array as 5 rows x 5 columns, each row, column element consists of 2 ccds of either horizontal or vertical alignment! Object is in 2nd row, 2nd column in the top ccd of the pair towards the bottom left of image.

Jon Jenkins, Kepler Co-Investigator, was, once more, kind enough to provide us an answer:

Ian is most likely seeing cosmic ray tracks which are the result of energetic particles whizzing through the CCD and depositing energy along the way. (I couldn’t tell from Ian’s email which direction he was counting CCD modules, although I found a bright cosmic ray track 2nd row, 2nd col from the top left, near the middle and low on the upper CCD in this pair.) We estimated a hit rate of 5 per square cm per second pre launch from counts reported by analysis of the LASCO CCDs aboard SOHO, which agrees well with the rates we’ve estimated from the dark frames we took prior to Dust Cover Ejection. The physics of our CCDs indicates that most cosmic rays deposit about 2500 electrons but some can deposit a whopping amount of charge. We identify and remove the “brightest” cosmic ray events from the data in ground-based processing. Most cosmic rays deposit too little energy for us  to detect them in or near the cores of our relatively bright target stars. The Field Of View (FOV) is tipped up 60 degrees above the ecliptic plane, so the chances of seeing solar system bodies is rather small, and Kuiper belt objects, for example, would not be bright enough to be seen as a bright streak in our images, and travel fast enough that to see them eclipsing stars in the FOV would require much shorter exposures than Kepler is capable of. The first light image pair consisted of one 6-sec integration (not including the 0.51 sec readout time) and one 65 sec integration (10 co-adds of individual 6-sec integrations with 0.51 sec readout times). During nominal science operations the CCD images are co-added for 30 minutes (a sum of 270 individual 6 sec exposures).

Cheers,
Jon

Homo Viator Manifest – Part I

What do we whitdraw from this fabled lands, from this enticing unknown islands at large?

We aim at a near return of Man, in full strength, to the Spirit of Adventure, towards a new quest, which was first dreamed, then imagined and finally sedimented in our species’ core, offering consistence, permitting no retreat, towards the next step, that must and will be, the embarking of members of the Human family, fellow creatures with the Beyond as flag, onboard a New Era of Discoveries.

 

Full document here (PDF file):

Homo Viator Manifest – Part I

Kepler opens a window on Mankind’s future…

Ah, but if even just a handful of them are orbited by planets as small as Earth, and if only a few of that handful of worlds are the right distance from their star to have liquid water… rivers, streams and seas… then when we look at that image we are looking at the destinations of the first interstellar probes – and beyond them, the first manned starships, whichever century they are built in.

Read more at Cumbrian Sky, BtC’s collaborator Stuart Atkinson’s blog.

The Ultreya Chronicles – I

btc_avatar_ruiWhere will we be 1000 years from?
Maybe here, maybe there, maybe everywhere, maybe nowhere…
Species come and go, they pop out and vanish at a same rhythm, some leaving no trace, others just a mere glimpse of their passage, what would make us, humans, different?
We have, nowadays, the possibility of creating the conditions for perpetuating our existence by diminishing the risk of extinction.
How? Doing what we have always done: Spreading.

Continue reading

Kepler Mission – Mr. Danvk, you have an answer.

In the aftermath of Kepler’s first light images a question made by danvk, a BtC reader, arrived our comment box:

In the full image there are lots of white lines that are perfectly horizontal or vertical. What are these?

Natalie Batalha, Kepler Co-Investigator, gives us a solution for the enigma:

The white streaks are CCD artifacts associated with the saturation that occurs with the very brightest stars in the field.  CCDs are constructed by putting very tiny electronic circuitry on top of a wafer of silicon.  When light strikes the silicon surface, the photons knock electrons loose.  These (negatively charged) electrons are attracted to tiny electrodes in the circuitry because they have a positive voltage applied to them.  The electrodes themselves define individual pixels.  A very bright star will liberate so many electrons that they pile up and literally spill over to the adjacent pixel (electrode).  They spill in the direction of least resistance and that happens to be in the direction that the electrodes are chained together (up and down the columns in our case).  When spillover occurs, we call this “saturation.”  In the image, you see that some of the saturation bleeds are vertical while others are horizontal.  The individual ccds (the rectangles) were mosaic’d so that we could rotate the spacecraft 90 degrees each quarter (to keep the solar panels pointing at the Sun) and still have the image look the same (rotational symmetry).  If you train your eye on the gaps between the rectangles, you can see that they form a bit of a spiral pattern.  That’s the rotational symmetry pattern due to the orientation of the individual CCDs.

Kepler mission – stellar smear and a grain of salt

After yesterday’s release of Kepler’s first light images and being marvelled by the telescope’s full field of view I was here wondering how would look one of the several raw images composing that breathtaking view into a sea of stars.

And, now that we’re into the real stuff and aware that we won’t hear of an Earth-like planet until the team has full confirmation, for when, hipotetically, could we expect one of those candidates to make its first appearance? How soon can it be?

Natalie Batalha answers:

Continue reading

Kepler mission – It’s full of stars!

Image credit: NASA/Ames/JPL-Caltech

Here’s what you have been waiting for, NASA Kepler’s full field of view – an expansive star-rich patch of sky in the constellations Cygnus and Lyra stretching across 100 square degrees, or the equivalent of two side-by-side dips of the Big Dipper.

And now let us stay with Jon Jenkins, Kepler’s Co-Investigator:

Continue reading

Titan from Cassini RADAR – Rosaly Lopes

Beyond the Cradle collaborator Rosaly Lopes starts her contribution to this blog with some words about Titan that will act as a teaser for the upcoming Cassini flyby of Saturn’s moon, to take place on April, 20 when the spacecraft will be at only 3600kms from the enticing moon. 

 

Understanding the geology of Titan is not easy. We mostly have low resolution data, the  Synthetic Aperture mode in the RADAR instrument gets down to about 350 m, but that is about it.

Compare that with Mars, where we can almost see the ants on the ground, if there were any… 

We have limited topographic data for Titan, and camera and VIMS instrument images are mostly low resolution. We don’t know the composition of the surface. So, there is still a lot we don’t know. But what we do know, thanks to Cassini, is very exciting. Titan is more Earth-like than anywhere else in the solar system. It has an atmosphere and a weather system, a “hydrological” cycle, only it’s not driven by water. It is driven by methane. Titan has methane rain, methane lakes and seas. We also see craters, but not many, indicating that the surface is young. We see river beds, and some rivers may still have liquid methane in them. We see dunes like those in the Namibia desert (where I’m hoping to go later this year).  

 

Scientists have used data from the Cassini radar mapper to map the global wind pattern on Saturn’s moon Titan using data collected over a four-year period, as depicted in this image. Image credit: NASA/JPL/Space Science Institute 

And we see volcanic features! They are not like those on Earth, they are cryovolcanic features, and the “magma” is water with probably ammonia or methane. We see craters that look like calderas, with flows coming out of them. We see many flows, though it can be difficult to tell which ones are volcanic and which ones are fluvial. Titan may even have active cryovolcanism. Three papers published recently (I was co-author of two of them) argue that brightness changes detected using the VIMS instrument are due to cryovolcanic activity. 

 

This infrared projection map of Titan was composed from images taken by NASA’s Cassini spacecraft, visual and infrared mapping spectrometer. The location of two regions that changed in brightness are labeled. These regions are hypothesized by some to be areas of cryovolcanic activity on Titan. Credit: NASA/JPL, University of Arizona 

RADAR sees flow features on these two areas. The correlation between the flows and the brightness changes makes a good case for cryovolcanism. We have not seen a thermal signal yet, so the flows may not be active. Maybe what we have is some kind of degassing or fumarolic activity that is causing the brightness changes. I hope that before Cassini is over we will see a thermal signal in one of the areas that are thought to be cryovolcanic. That would be really great!

 

For more information visit the mission’s website.

Moonlets shadow

cassini_m

Do you want to see discovery as it happens?

And how YOU can make the difference?

Run to the unmannedspaceflight forum where one of its members has spotted the shadow of, not one, not two but thousands of moonlets in one of Saturn’s rings.

Great catch Floyd!

 

[EDITED] Beyond the Cradle most recent collaborator, Sarah Milkovich, Cassini Science Planning Engineer, provided us with some context for the current situation:

 

Currently, we are approaching Saturn’s equinox.  Like the Earth, Saturn’s spin axis is tilted, so as Saturn moves through its orbit, the sun shines on different portions of the planet.  The sunlight is in the process of moving from the southern to the northern hemisphere, and at equinox it will cross the rings.  The sun will shine on the edge of the rings, casting a very thin shadow onto Saturn, and the rings themselves will be dark.

So right now, the sun is getting lower with respect to the rings, which means that the shadows cast by the moons are getting longer, (which you can see in these images and movies on the imaging team’ website), and if there’s enough vertical relief within the rings we can see shadows from that as well. All of this will allow us to see more of the structure and variations within the rings themselves.

We’re also going to be looking at how the changing illumination conditions (and therefore changing temperature distributions) affect the moons and the atmosphere of Saturn itself. We’ve already begun to see some changes in the color of Saturn’s northern hemisphere – this is a mosaic of images taken in 2004, and you can see that the northern hemisphere (where it isn’t covered in shadows from the rings) is blue.  Compare that to this image taken in 2008, and you can see how the northern hemisphere is more golden, with a hint of blue at the pole. 

The Saturnian equinox will occur in August, so expect to see more changes in the future!

April 12, 1961

To Go. Just Go. Where the will leads the step.
To Go. Just Go. Where the calling echoes.
From the journey to be to the territories to discover.
To Go. Just Go.
Having the moment as compass and ourselves as the hurdle to overcome.
Win the desert, the mountain, the valley, the sea, the beyond. 
Crawling, walking, sailing, flying. 
To Go. Just Go. Stumbling, falling, rising. Always was, always will be our path.
We are what we listen, what we sight, what we walk.
To Go. Just Go.
To the corners of the Earth, to the corners of the Universe, 
to the corners of ourselves.
There is a wind, precursor of a new departure.
We are, once more, aiming at the distance.
To Go. Just Go.
We are the whole quest.
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