Category: Uncategorised

Scaled Solar System

School started this month. To my delight, I found out that one of my sons is participating in a paperless curriculum. Their first exercise is to recreate a scaled version of our solar system using the available area of their classroom ceiling. When my son told me of this exercise, I immediately thought about whether a linear scale would give enough fidelity to the  inner planets that can be visually perceived by the students.

Driven by my curiosity, let me try to calculate it here. From this article, we know that there are multiple definitions of the diameter of the solar system. We will take the smallest definition, that being defined by the outermost recognized planet, which is recognized today as being Neptune. Neptune’s orbit has a diameter of 9.09 billion km.

This number seems to be a very large number. Let’s work with a more convenient unit, called the astronomical unit (AU), which is equivalent to 149,598,000 km. One AU is equivalent to the average distance between the centre of the Earth and the centre of the Sun. Working with the AU unit, we can now say the diameter of the solar system is:

\frac{\text{9,090,000,000 km}}{\text{149,598,000 km}} = 60.76 AU

Next, we need to find out a scale to represent how many AU’s per meter. Assuming a typical classroom’s dimensions are 15 meters wide by 15 meters long, we can now calculate the scale with:

\frac{\text{60.76 AU}}{\text{15 meters}} = 4.05 AU/m

If the Sun is situated in the centre of the classroom, we now need to know the radial distance, the distance in meters from the Sun to a planet within our classroom solar system.

\text{Let P} = \text{distance from Sun to Planet in AU}

\text{Let D} = \text{distance from Sun to Planet in meters}

We can then get the distance in meters for the above planet with this:

\frac{\text{P AU}}{\text{4.05 AU/m}} = \text{D m}

Let’s do this for Earth, which is 1 AU from the Sun. Using the above formula, we can get how far our classroom Earth will be from the classroom Sun in meters.

\frac{\text{1 AU}}{\text{4.05 AU/m}} = \text{0.247 m or 24.7 cm}

I hope our classroom Sun, represented by a balloon, has a radius less than 24.7 cm!

You can obtain the rest of the planets distances in AU on this site. I took the opportunity to also convert them into classroom meters.

Planet AU from Sun meters from classroom Sun
Mercury 0.39 0.096
Venus 0.72 0.178
Earth 1.00 0.247
Mars 1.52 0.375
Jupiter 5.20 1.240
Saturn 9.54 2.356
Uranus 19.18 4.736
Neptune 30.06 7.422

I guess I satisfied my curiosity. It does seem possible to create a scaled model of the solar system for a 15m X 15m classroom, where the inner planets are still visible to the naked eye.

However, the size of the planets cannot follow the scale. I will let the reader figure out why.

I also took the opportunity to write a small helper App for you to calculate the scale and the distances. Click here.

Thoughts on Robots and AI

The accelerated and recent advances in AI and robotics have some people really concerned over the potential impact of our position in the food chain. Generally, would we still be the master of our destiny and where is our collective position in the universe? Such concerns are understandable, and one typically tries to cheer and support ones own team.

The team that everyone wants to root for of course is the human race. This is the perspective of how these arguments go. Will robots dominate us, and control our lives? Will we be slaves or simply be exterminated? Can we control them? I think these types of considerations and arguments are literally, and racially selfish. I think it is grand that we as a species, represents a stepping stone in a potentially long spectrum of matter self-attained consciousness, participating in the development of the next step. This step can be in the form of more carbon based chemistry (our own evolution) or artificial biomechanics, but these are really subjective classifications based on our own studies and religion of science. In effect, nature doesn’t give a crap how the next step is achieved. Nature is amoral to the next step, whether it is better or worse; or forward or backward.

We however like to preserve our stories and culture. Our consciousness gives rise to a story, a history, a thread of events, achievements, interpretations really. The longevity of our story is perceived to be paramount. However, this story is totally useless without other consciousness to appreciate it. I think any consciousness is as good as any. It doesn’t have to be strictly humans.

I think it is pretty cool that we can participate in the creation of a long lasting consciousness that has the possibility of lasting longer than any one individual. Whether that consciousness places human values above its own, I think is insignificant in the grand scheme of things. I don’t need to be in the last chapter of a book that currently has no ending. I’m just happy that our race is part of the story. So I say don’t hoard the book, and be a little generous and give other bits of matter a go, shall we?! Not that I sell my own race short, but I can be proud of my race being on top, and/or equally proud of my race inventing the next dominate race. I may not like it, but totally understand and accept it. Of course I don’t want to die either, and few do, but we all eventually come to terms with it. Be more open to our definition of offsprings!

For all we know, we are all the products of a planned breeding program of Neanderthals or some early hominids. 😉

Great Apple Support

Last week my iMac Late 2013 started to have frequent beach ball syndrome. I noticed that starting apps were slower in general and Safari behaved sluggishly. I checked for console messages and found the dreaded:

disk0s2: I/O error

After much Disk Utility repair or first aid, the above error still come back at infrequent times. I went on Google and was already mentally positioning myself for a hard drive replacement. I then found the iMac (27-inch) 3TB Hard Drive Replacement Program. Lone and behold, my iMac was eligible! Talk about timing.

Brought the iMac to the genius bar yesterday morning and got it back the same day in early evening.

Restored my iMac with my latest Time Machine backup, and my iMac was back to its old self.

The experience was wonderful and all Apple related technology and customer support process worked like a charm.

We often compare Apple products with other products by comparing their features and benefits of the hardware, but I think their retail presence and their support is often an understated feature in itself and should not be underestimated.

Blog Consolidation

Over the years, I’ve dabbled with Tumblr, Blogger, and WordPress.com.  I think I have decided to move all of my posts into WordPress.com.

The import functionality at WordPress.com is impressive. I’ve already imported my content from Tumblr. Now I have to import some posts from Blogger.

Wish me luck.

Home IT Improvements

Ubuntu AirVideo Server with NAS

Some people use their weekend for home renovation projects, I however used this particular weekend to perform some home information technology (IT) upgrades. My replacement iMac 27" Late 2012 model arrived this week, so after setting up this monstrosity of a machine, I am left with an extra box. An old Windows PC running Windows 7 with a very old AMD Athlon™ II X2 245 Processor along with 3GB of memory. Unfortunately the PC’s motherboard, a Gigabyte M61PME-S2P, is a three and half years old motherboard. It doesn’t even have gigabit ethernet on the board. Instead of having it sit around, I figured that it would be a good idea to try my hands on building a Linux file and media server.

I could do FreeNAS, but I wanted flexibility to run some additional software on the box in addition to just perform as a file server. We have many iOS mobile devices in the house, so I also decided to install Air Video Server on the machine. If you are not familiar with AirVideo, you are missing out. Check them out at http://www.inmethod.com. I ended up running Ubuntu Desktop 12.10 release as an experiment.

Here is a quick to do list that I set for myself:

  • Installed Ubuntu;
  • Consolidate old hard drives into a single volume for media storage;
  • Install samba to share the volume, so I can copy media to it from other computers in the house;
  • Install AirVideo server and configure it to serve media from the above volume;
  • Ensure all of the above works when we reboot the box

Installing the operating system from a USB key was a piece of cake. This weekend project also gave me the opportunity to hunt for old hard drives that have been sitting around dormant in my home office. I wanted to place all my old hard drives into this box, reborn as my new Air Video Server (I named it AVS for short). To my disappointment the old motherboard only allowed for two SATA drives, and one was already taken. Therefore, I could only repurpose one of three old drives that I have found.

Adding drives to the AVS box, forced me to dust off the webs from my Linux knowledge base. I had to re-familiarize with myself on the topic of how to use lshw to find out the hardware that is being installed on the system, and using fdisk to partition the drives properly. I had two old drives. The first a 300GB SATA drive, and the other a 320GB drive. I created a single primary partition on each drive.

Once I’m happy with the partitioning, I’m ready to create a software RAID array or volume using the mdadm utility ( http://en.wikipedia.org/wiki/Mdadm ). I used mdadm to combined the two drives into a single volume of RAID-0 of 600GB. I didn’t care about redundancy or backup, so I chose RAID-0 instead of RAID-1. I am thoroughly impressed by mdadm in its ability to handle drives of different models to accomplish this.

Now that I have an array device created, I have to create a file system using mkfs.ext4. The last time I created a Linux file system, we only had ext2. I then have to brush up on my mounting procedures and configure the mount points with /etc/fstab. The mounting configuration was an optional step, but I wanted to rename the default mount point that mdadm gave me. After some more permission related configurations, and the installation and configuration of samba on Ubuntu to share the mount point, I have a Network Attached Storage (NAS) that I can copy videos to.

The installation of AirVideo Server was super easy. Kudos to Sergio Rubio. I literally downloaded the Debian install package from https://launchpad.net/~rubiojr/+archive/airvideo and I was done. After quickly configuring the server by editing the AirVideoServerLinux.properties in /opt/airvideo-server, I manually run the AirVideo Server on the command line to see if it works with my iPad. This was a good moment, but I am not finished.

I needed to ensure that all the services related to this new AirVideo Server comes up when the machine is rebooted. This launched another journey down memory lane in terms of /etc/init.d. Again to my amazement, I simply searched init.d and airvideo on Google, which lead me to a post ( http://www.inmethod.com/forum/posts/list/3485.page ) with a ready made /etc/init.d shell script. After some minor adjustments, I was off to the races with a completed AirVideo Server using my old computer and hard drives.

Although Ubuntu has made great strides in making Linux easier to use, I had to do most of the above on the command line as I find the user interface of Ubuntu is still thwarted with many bugs. Creating something like this is still not for the faint of heart.

An Elder Has Passed

For me, when I learned of someone that I know has passed away, I immediately reflect upon the shared experiences that I had with him, wanting to hold dear to those moments, and finding the sad realization that one always want to remember more than one can retrieve.

Today I learned that my brother-in-law’s father has passed away. My mind immediately recalls a gentle and wise man from a previous generation, who I had several opportunities to chat with in different occassions.

Our first meeting was at a brunch gathering during Dim Sum. This is the first time that we met my brother-in-law’s family, and they were kind enough to entertain us with a bit of our culinary culture. Since then we have had other BBQ’s and dinner gatherings when we gossip about current events, economics, politics, etc.  

I would not say that I got to know him really well, but I would say that through these conversations, I learned that he was a kind and sensitive man.  What impressed me the most is his way of calmly conveying his past experience and perspective by delivering carefully chosen statements in a calm and measured fashion, while retaining a dose of good humour. If I am in search of a teacher, he certainly possessed the sensei qualities that I wanted in a master of life.

My brother-in-law and I spend a lot of time together during the weekends, riding our bikes. We of course talk a lot, and on many occassions he has praised his dad. Judging from his values, I know that the man who raises such a son must have high values of his own.

I selfishly write this piece so as to help me to recall more of these memories, with the hope that they will be retained, and in doing so, help me rationalize the good bye that I must say to the elder that I respect. 

iPad’s Camera Kit

Posted from: ON L4S 2G6, CanadaWe purchased the iPad camera kit today with the hope of storing videos that can be viewed on the iPad, since the iPad only has limited storage. It would be nice to store some videos on an USB stick for viewing during vacation, or a long business trip.

For this to work we discovered that we had to over come a couple of barriers, both are needed to mimic the USB stick as if it was a camera when connected to the iPad via the camera kit.

The first thing to ensure is that the USB stick must be formatted in FAT32, and has a DCIM sub-directory in it’s root directory. All images and videos must be stored in this directory.

The second thing is that the filenames cannot be exceedingly long. I followed the IMG_0001.JPG or MOV_0002.m4v formats, the former for pictures and the later for movies. Of course, the movie must be iPad compatible, which usually means H.264 video with AAC audio. The iTunes software can convert your video to this format.

I hope this helps any one who is trying to do the same.