Archive for the ‘Space’ Category

Here are a number of interesting courses, two of which I am looking at for the past two weeks and that i would hopefully finish by the end of August-September.

Introduction to Neural Networks (MIT):

These days, amongst the other things that I have at hand including a project on content based image retrieval. I have been making it a point to look at a MIT course on Neural Networks. And needless to say, I am getting to learn loads.


I would like to emphasize that though I have implemented a signature verification system using Neural Nets, I am by no means good with them. I can be classified a beginner. The tool that I am more comfortable with are Support Vector Machines.

I have been wanting to know more about them for some years now, but I never really got the time or you can say the opportunity. Now that I can invest some time, I am glad I came across this course. So far I have been able to look at 7 lectures and I should say that I am MORE than very happy with the course. I think it is very detailed and extremely well suited for the beginner as well as the expert.

The instructor is H. Sebastian Seung who is the professor of computational neuroscience at the MIT.

The course has 25 lectures each one packed with a great amount of information. Meaning, the lectures might work slow for those who are not very familiar with this stuff.

The video lectures can be accessed over here. I must admit that i am a little disappointed that these lectures are not available on you-tube. That’s because the downloads are rather large in size. But I found them worth it any way.

The lectures cover the following:

Lecture 1: Classical neurodynamics
Lecture 2: Linear threshold neuron
Lecture 3: Multilayer perceptrons
Lecture 4: Convolutional networks and vision
Lecture 5: Amplification and attenuation
Lecture 6: Lateral inhibition in the retina
Lecture 7: Linear recurrent networks
Lecture 8: Nonlinear global inhibition
Lecture 9: Permitted and forbidden sets
Lecture 10: Lateral excitation and inhibition
Lecture 11: Objectives and optimization
Lecture 12: Excitatory-inhibitory networks
Lecture 13: Associative memory I
Lecture 14: Associative memory II
Lecture 15: Vector quantization and competitive learning
Lecture 16: Principal component analysis
Lecture 17: Models of neural development
Lecture 18: Independent component analysis
Lecture 19: Nonnegative matrix factorization. Delta rule.
Lecture 20: Backpropagation I
Lecture 21: Backpropagation II
Lecture 22: Contrastive Hebbian learning
Lecture 23: Reinforcement Learning I
Lecture 24: Reinforcement Learning II
Lecture 25: Review session

The good thing is that I have formally studied most of the stuff after lecture 13 , but going by the quality of lectures so far (first 7), I would not mind seeing them again.

Quick Links:

Course Home Page.

Course Video Lectures.

Prof H. Sebastian Seung’s Homepage.



This is a Harvard course. I don’t know when I’ll get the time to have a look at this course, but it sure looks extremely interesting. And I am sure a number of people would be interested in having a look at it. It looks like a course that be covered up pretty quickly actually.tornado

[Image Source]

The course description says the following:

The amount and complexity of information produced in science, engineering, business, and everyday human activity is increasing at staggering rates. The goal of this course is to expose you to visual representation methods and techniques that increase the understanding of complex data. Good visualizations not only present a visual interpretation of data, but do so by improving comprehension, communication, and decision making.

In this course you will learn how the human visual system processes and perceives images, good design practices for visualization, tools for visualization of data from a variety of fields, collecting data from web sites with Python, and programming of interactive visualization applications using Processing.

The topics covered are:

  • Data and Image Models
  • Visual Perception & Cognitive Principles
  • Color Encoding
  • Design Principles of Effective Visualizations
  • Interaction
  • Graphs & Charts
  • Trees and Networks
  • Maps & Google Earth
  • Higher-dimensional Data
  • Unstructured Text and Document Collections
  • Images and Video
  • Scientific Visualization
  • Medical Visualization
  • Social Visualization
  • Visualization & The Arts

Quick Links:

Course Home Page.

Course Syllabus.

Lectures, Slides and other materials.

Video Lectures


Advanced AI Techniques:

This is one course that I would  be looking at some parts of after I have covered the course on Neural Nets.  I am yet to glance at the first lecture or the materials, so i can not say how they would be like. But I sure am expecting a lot from them going by the topics they are covering.

The topics covered in a broad sense are:

  • Bayesian Networks
  • Statistical NLP
  • Reinforcement Learning
  • Bayes Filtering
  • Distributed AI and Multi-Agent systems
  • An Introduction to Game Theory

Quick Link:

Course Home.


Astrophysical Chemistry:

I don’t know if I would be able to squeeze in time for these. But because of my amateurish interest in chemistry (If I were not an electrical engineer, I would have been into Chemistry), and because I have very high regard for Dr Harry Kroto (who is delivering them) I would try and make it a point to have a look at them. I think I’ll skip gym for some days to have a look at them. ;-)


[Nobel Laureate Harry Kroto with a Bucky-Ball model – Image Source : richarddawkins.net]

Quick Links:

Dr Harold Kroto’s Homepage.

Astrophysical Chemistry Lectures


Onionesque Reality Home >>

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It is logical to believe that there exist millions of planets in the “vicinity” of our part of the universe alone. However, limited due to tools and the extremely vast distances to be dealt with, we have only been to locate about 300 extra-solar planets, and these have been located indirectly. That is, by observing gravitational wobbles by tracking the star over a period of time it can be known if it is tugged at by an object like a planet.

Why is it difficult to Image the actual planets, one might ask? Well the reason is simple, the distances we deal with are so huge the star simply outshines the planet, making it very difficult to image the planets moving around the star. How does one avoid this problem? The idea is very practical. A occulting bar is used to block out the brightest part of the star’s image so that the blinding light is reduced. Other more specialized techniques can improve things by reducing the light further.

Also another strategy used by professional astronomers looking into deep space for planets over the last two decades has been to focus on systems expected around young stars. The reason being that if the formation of the planetary system is recent the planets would be significantly brighter from the heat of their formation. Much like our early solar system. It would be very difficult to look into space for a planet that is nestled in a star system like that of our Sun of today. This is because the planets would be very very faint (as they would be older and hence colder) and hence very very difficult to image.

However for the first time we have ACTUALLY been able to see extra-solar planets. This is a HUGE step, culminating from years of painstaking observations and focus. These planets are gaseous and probably will have no trace of life. However, the fact that we have been able to image them has a LOT of meaning. Some astronomers have said that it might not be very fantastic to think that we might in a very short time vector be able to observe some Earth like planet that is more likely to have life (carbon based, atleast of the type we know), now this is something that one could not even THINK of some years ago. It was probably fantasy to think we could be able to image planets like our own, now suddenly it looks quite possible.

The first image below, taken by the Hubble telescope shows a ring of dust surrounding the star Fomalhaut (derived from the Arabic فم الحوت fum al-ḥawt, meaning “mouth of the whale”) which is only 25 light years away in the constellation Piscis Australis. This star can be seen with the naked eye in the night sky. The lower right inset image is a composite image from the images taken in 2004 and 2006. Paul Kalas and his team of the University of California at Berkeley found out the planet.  This planet completes orbit around its star every 872 years.

fomalhaut[Image Source: HubbleSite]

The radial streaks are scattered starlight. The planet’s temperature is 260 degrees, quite cool compared to other exoplanets. This dot is about three times the weight of Jupiter and about three times as far from the star as compared to how far Pluto is from our sun. This dusty ring around Fomalhaut is suspected to be something like the Kuiper belt of our solar system.

This star system was expected to have planets in 2005.

The following is a video on the same:

A ring of dust surrounds the star Fomalhaut. Images taken with the Hubble Space Telescope in 2004 and 2006 show that a white dot just inside the dust ring moved in the intervening two years. Researchers believe the dot is a planet that weighs no more than 3 Jupiter masses and lies about three times as far from its star as Pluto does from the Sun (Courtesy of Paul Kalas/UC Berkeley)

Yet another fantastic finding was the discovery of a planetary trio orbiting the star HR 8799 in the constellation pegasus. About 130 light years away, the planets found are from 7-10 times the size of jovian Jupiter. With the farthest of the lot sitting at a distance of 68 AU from HR 8799 (1 AU is the distance between the earth and the Sun). These planets are still glowing because of the heat resulting from contraction after their formation. Their orbit was measured by far IR techniques at the Keck and Gemini North telescopes in Hawaii.


This near-infrared composite image shows the nearby star HR 8799 (multi-coloured blob) and its three planets (red dots at upper left, upper right and just below the star). The planets are 7 to 10 times as massive as Jupiter (Image: National Research Council Canada).

Wow! I am awed once again by the ability of astronomers to find out even the most obscure of dots amongst a nasty conundrum of dots. And even more by the discovery itself. And let me not talk about the images we have above.

I have always harbored a fantasy, that is to be on the crew of humans who get to travel to such a far off land on a Super Daedalus or Super Orion type space-ship. It would take some years (space-ship time). But ofcourse when I return to Earth I would not find anybody I know. For, centuries would have passed as per Earth time by the time I get back. ;)

Onrionesque Reality Home >>

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The first Indian lunar probe the Chandrayaan I (in sanskrit, संस्कृतम् Chandra = moon ; Yaan = Vehicle . So, literally it means moon craft) beamed back its first pictures of the earth that it took as the ISRO (Indian Space Research Organization) has been testing the cameras on Chandrayaan.

The terrain mapping camera aboard Chandrayaan, which is a black and white imager, had been turned on for testing. It relayed back two test images, one taken at a height of 3,000 km and the other at a height if 70,000 km. The Pictures can be found and viewed in higher resolution here.

Update (15 November): Chandrayaan has now started sending pictures from the Moon,  this post was written only for the pictures sent back of the Earth while testing the terrain mapping camera. Find them at the end of this post.

[Pictures of home never grow old ]

Click to Enlarge

The Chandrayaan was launched on the 22nd of October by India’s old warhorse the PSLV (C11) into an initial elliptical orbit around the Earth. Like many I was skeptical about the logic for such a mission when it was announced a few years ago. I just thought there was no real logic in doing an exercise that would essentially be a re-invention of the wheel. Over time my view refined by more information about it has changed. I will come back to this in just about a while.

Ofcourse one would say anything to do with space research is a show of a countries growing economic clout and it commands immediate respect. True, but that is not why I think it is not a futile exercise.

Inexpensive, So why not do it? Some argue that though India is growing rapidly and is projected to over take many major European economic powerhouses by 2015-2020 (It is already ahead of them in PPP terms though still has a long way to go in nominal GDP terms) and countries like Japan by the 2030-35, it still has a lot of people under the poverty line and the standard of living remains low. So it is only a waste of money. Well, the Chandrayaan I only cost $80 million, the cheapest moon mission of comparable scales by far. And this much money is meager when you look at an elephant like economy really (to give you an idea, the Boeing 747-8 costs US$285.5-300 million according to 2007 prices. So the mission that way cost nothing really, so the whole talk about India wasting money has very little ground.

To Avoid a Possible Space Apartheid: The NPT is always billed as an unfair treaty by three nations that refuse to sign it – India, Israel and Pakistan. Their argument being that the provision of the treaty that allows the countries that made atomic weapons before 1967 to keep weapons, and to continue their development and to disallow and to impose sanctions on countries that try to develop weapons later is unfair, and there is no reason stated why such a distinction is made. India has advocated disarmament as a complete solution.

Anyway, I have always thought that an international agency should hold a minimum number of weapons and all the other countries should give up their nuclear weapons over time. This reserve should be kept only for a very unlikely doomsday scenario in the future that might require mankind (stress added) to intercept a comet on collision path towards the Earth with an Orion like super missile. This is extremely unlikely, but one can never totally rule out the chance even in a medium term time vector.

Coming back, if in a similar manner, in the medium term future there is a possibility of some select countries to set up a base on Mars or on the Moon, then it is possible that countries who made a mark in space till a specific date might only get to join. And it might just end up being like the NPT. So making a mark is a wise thing to do. Though again this is a sort of an outlandish argument.

Now coming back to the main argument that was it worth it to send a mission that is like doing boldly what others have done before. What new is left on the moon to be looked at, absolutely nothing? I think it is not something like that, and it is definitely worth it. Let’s get a sense of history first to see why.

A Little History: The Moon always has been an object of wonder since the stone age man. Many rock paintings have featured the moon. Over the ages people have looked up with amazement on what it was and what was on it. Most religious beliefs accorded it to be an immutable creation of God and some gave the Moon the status of god.

This notion was first challenged in recorded history by the observations of the Canterbury Monks in 1178 (June 18), who recorded an explosion on the moon, which was in recent times confirmed as a comet striking the moon. By the middle ages it was fairly recognized that the moon was a sphere though mostly it was held that it had a smooth surface. The heretic Galileo Galilei was the first to draw images of the moon that challenged this view. Clearly, the telescope was the first giant leap in the exploration of the moon. Over time it was recognized that the moon had a surface as terrestrial as on Earth and that there was nothing heavenly about the moon. For some centuries for the want of tools, there continued to be speculations about the nature of moon and life on it.

Speculations are always a part of any space exploration or thought process, they only aid in further development of tools to explore them, the present one being speculations (though more studied and calculated than the ones we had 500 years ago ofcourse)  about water or He3 on the moon. The absence of tools gave rise to wild speculations like in the great moon hoax of 1835 a number of people were led to believe that there were strange beings living on the moon.

The era of modern exploration of the moon began with the Luna 1 (also Mechta : Russian word meaning Dream) of the former Soviet Union.

[The Luna 1]

It was the first human made object to reach the vicinity of the moon. The subsequent cold war race between the Soviet Union and the US culminated in 1969 with the landing of the first humans on the moon. Till then they had sent about 40 spacecrafts to map and study the lunar surface in great detail. After the first moon landing about a dozen men landed on the moon. They were as follows:

Apollo 11 [July 20, 1969]:
1. Neil Armstrong “One small step for (a) man, One giant leap for mankind…”
2. Buzz Aldrin

Apollo 12 [November 19-20, 1969]:
3. Pete Conrad
4. Alan Bean

Apollo 14 [February 5-6, 1971]:
5. Alan Shepard
6. Edgar Mitchell

Apollo 15 [July 31-August 2, 1971]:
7. David Scott
8. James Irwin

Apollo 16 [April 21-23, 1972]:
9. John W. Young
10. Charles Duke

Apollo 17 [December 11-14, 1972]:
11. Eugene Cernan
12. Harrison Schmitt

The Soviets mainly relied on robotic explorers to collect rock samples whereas the above astronauts got about 400 kg of soil and rock samples back to earth for investigation. After the end of this race the interest in the moon significantly waned. Was there anything left to know about the moon that would interest us at all?

Moon Mysteries:

>> Though we know the maximum about the moon as compared to any other celestial body other than our own planet, we still know very little about it.

>> The Moon is 4.5 billion years old and is a witness to the countless mysteries about the solar system we are not aware of. It still has a lot to offer. And its proximity would only help us in this quest.

>> Comprehensive lunar surveyors like the Clementine gave us a lot of new insight, but a lot remains to be known.

>> The origins of the moon are not known well enough. According to one hypothesis that has maximum currency today is that a large object collided with the Earth and resulted into debris that eventually formed the Moon.

How the Chandrayaan is Not A Reinvention of the Wheel:

1. The chief advantage that the Chandrayaan has is that it carries instruments that can survey the Moon in extensive detail like never before. This could lead to various new insights. It could map the Moon using the visible, UV, IR, X-Ray, Low Power Gamma ray and radar. This would give a detailed 3-D atlas of the moon and also a sound picture of its chemical composition.

The probe is expected to orbit the moon for two years, in this period if suppose there is a solar flare, then the x-rays emitted from the Sun could cause the iron on the Moon to emit characteristic X-rays which could be analysed by the Imaging X-Ray spectrometer. Also, this data could be used by the Hyper Spectral Imager and the Moon Mineralogy mapper to find out the amount of Iron on the Moon.

2. Water on the permanently shadowed regions of the poles of the Moon was a distinct possibility that was indicated by the Clementine mission, the Chandrayaan could go a long way in investigating this further.

3. There are many other objectives that the Chandrayaan is expected to work at.

For more details look here

Update (15th November): Chandrayaan has now started sending back images of the Moon and some have been released by the ISRO. They can be found over here:

One of them below was taken by the TMC in orbit.


[Photo Source: Indian Space Research Organization ]

Click to Enlarge

In conclusion, one thing is for sure. World competition for space is now a thing of the past IMHO and space agencies around the world would only co-operate for working towards the overall benefit of mankind.

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