NASA Picture of the Day - The First Color Panorama from Mars by Curiosity
You’ve just landed on Mars and opened your eyes — what do you see? If you’re the Curiosity rover, you see a strange gravelly place with a large mountain in the distance. You’ve landed on target near the edge of 150-km wide Gale Crater, with Mount Sharp on the horizon being the rise in the crater’s center. As a car-sized rover with six wheels and a laser, you prepare yourself to go on a two-year mission of exploration, climbing Mt. Sharp, and looking for signs that Mars once harbored life. Currently you sit motionless, check yourself over, and receive a detailed briefing from Earth on things you will need to know while rolling around, trying to avoid flipping over or getting your wheels stuck in sand. Your rolling explorations will likely start in a few days. What will you find? What’s out there?
How the Moon Affects the Date of Easter
This year, the astronomical date to start spring was March 20th, 2012. The first full moon after the start of spring is typically called the Paschal Full Moon, or the Paschal Term. Traditionally, Easter is observed on the Sunday after this Paschal Full Moon. For this year, it works out quite nicely - the Paschal Full Moon will land on Friday, April 6th - and Easter will be April 8th. Ever since Pope Gregory XIII decreed this in 1582 as part of the then ‘new’ Gregorian Calendar system, we have used it ever since.
Using this system, Easter can call anywhere between March 22nd and April 25th! However, there is also the “ecclesiastical” full moon, which is determined from ecclesiastical tables - but this occasionally does not coincide with the astronomical full moon, based on more accurate calculations. So this system is not perfect, as the ecclesiastical and astronomical systems sometime differ. For example, in 2038, the vernal equinox will occur on March 20th, with a full moon the very next day. Astronomically speaking, Easter should be March 28th - but the church has mandated that it will occur on April 25th instead.
Once these discrepancies were noticed, a proposal to change Easter to a fixed holiday was largely accepted - and in 1963 the Second Vatican Council said that it would agree. The usual date for Easter is the second Sunday in April - which works out this year.
Solar Eclipse vs. Lunar Eclipse
Although many people confuse the terms and use them interchangeably, there is, of course, a distinct difference between these two types of eclipse. As soon from Earth, a solar eclipse is when the Moon passes between the Sun and the Earth - effectively blocking out the sun. In this case, one would only seen the moon, with a bright ring around it (shown above on the left.) Seeing the moon is what causes people to confuse it with a lunar eclipse. Solar eclipses can only happen when the lunar calendar is in the total eclipse phase. A solar eclipse does not necessarily mean the entire sun is blocked out - but this is called a total solar eclipse.
Interestingly, if the moon was in a perfectly circular orbit - there would be a total solar eclipse during every new moon, or once a month. Unfortunately, the Moon’s orbit is angled at about 5 degrees relative to the Earth’s orbit, so it doesn’t line up as often! Don’t believe it when people say it is safe to look directly at the eclipse, it is still dangerous!
In contrast with only occurring during a new moon, a lunar eclipse can only occur during a full moon. During a lunar eclipse, the Earth is aligned in between the Moon and the Sun - exactly or as closely as possible. In this way, the Earth blocks the Sun’s rays from striking the Moon directly.
Additionally, solar eclipses can only be seen from small areas of the Earth - while a lunar eclipse can be seen anywhere on whatever is the night side of the Earth at the moment. Lunar eclipses also last much longer, a few hours compares to a mere few minutes!
This new video from NASA shows you exactly what it would be like if you were strapped to one of the shuttle’s solid rocket boosters and given an HD video camera to hold. It’s a wild ride.
As these cannons of chemical fire thrust the shuttle through the lower atmosphere, you can see the ground zoom away, the sky begin to fade into the darkness of space, and even the exact point where the shuttle breaks the sound barrier on its way to orbit (~1:10!).
There’s a speedometer in the upper right and some amazing sound remastered by Skywalker Studios. This is the best trip you’ll take all Thursday (or really any day).
Sir Ernest Rutherford, President of the Royal Academy, and recipient of the Nobel Prize in Physics, related the following story:
“Some time ago I received a call from a colleague. He was about to give a student a zero for his answer to a physics question, while the student claimed a perfect…
The Four Fundamental Forces.
In Physics, the fundamental forces describe how particles interact with one another. The four known forces are the Strong Nuclear Force, the Weak Nuclear Force, Electromagnetism and Gravitation. These forces are considered fundamental because they cannot be explained in terms of any other force. The quest to bring together the four forces into a single entity (a TOE - Theory of Everything) is the pursuit of many physicists, but so far has proven to be a challenging task, which even eluded Einstein himself!
Strong Nuclear Force
Strength: 1 (All strenghts to follow are relative to this one.) Range: 10-15 m
The Strong Nuclear Force, aptly named because it is the strongest of the four forces, is responsible for everything that we know today. This force holds together the protons and neutrons together in the atomic nucleus despite the particles’ urge to repel each other. The mediators of the Strong Nuclear Force are particles called Gluons, which also hold quarks together to form particles such as the proton.
Strength: 1⁄137 Range: Infinite
The Electromagnetic force is responsible for, as you can probably tell, electricity and magnetism. This force is mediated by Photons, massless particles that are the basic unit of light. You probably know that opposite charges attract, and like charges repel - this is a direct result of the Electromagnetic force. When a particle attract or repels another particle, what actually happens is that photons are exchanged, and the release or absorption of the photon’s energy causes the particle to come closer or dart away. This force is responsible for many everyday, observable occurrences. The Electromagnetic force is why your computer isn’t falling right through your desk right now; because the atoms in your computer and in the desk resist being displaced from the exchange of photons.
Weak Nuclear Force
Strength: 10-6 m Range: 10-18 m
The Weak Nuclear Force is the most unfamiliar to us in our everyday lives. However, it is the force that is responsible for radioactive decay and hydrogen fusion in stars. The mediators of this force are the massive W and Z bosons. This force is also capable of changing the flavor of a quark, i.e. changing one type of quark into another.
Strength: 6 * 10-39 m Range: Infinite
Gravity, of course, is the most familiar of all the fundamental forces. However, is it also the least likely to compromise, as it has proven extremely difficult to associate gravity into the other forces into a Theory of Everything. In fact, the modern model of the Universe, the Standard Model, does not even include gravity because of this! In short, Gravity is a force by which physical bodies attract each other. In more precise terms, Gravity is an inverse square law with incorporates the masses of two bodies, the gravitational constant, (6.67300 × 10-11 m3 kg-1 s-2,) and the distance separating the bodies. Gravity is most observable by providing weight to objects and what causes objects to fall to the ground when dropped. Gravity also causes coalesced matter to remain intact, thus accounting for most of the macroscopic objects in the Universe. Every object exerts a gravitational force on every other object, although the force becomes extremely weak at large distances.
To show the weakness of Gravity compared with the other forces, consider this. After running a comb through your hair several times, place it close to a flat piece of paper. If done correctly, the paper should lift up and touch the comb. An entire planet’s gravity was required to keep that piece of paper down, but a simple comb with a few charged particles was able to pick it up!
I love deGrasse Tyson. So much.
“What’s your elevator pitch?”
“Excuse me? The congresspeople work for us! If you can’t sit there and fucking stand longer than an elevator ride what the hell country am I living in?”
Neil DeGrasse Tyson on why we should double the budget of NASA and go to Mars. Watch it till the end, NDT says more than one thing which had me applauding him.
The absolute best.
On Wednesday, September 14, the U.S. Senate subcommittee overseeing NASA’s budget – the Subcommittee on Commerce, Justice, Science, and Related Agencies — will meet to “markup” the bill that will provide the space agency with the money it needs to do its job of exploring space.
The next day, Thursday, September 15, their markup will go the full committee on for their markup.
Somehow, the U.S. Senate has decided it can move quickly – to decide the fate of space exploration for the next year and beyond.
Action time for space-lovers! This is key to America’s innovation. Don’t let the budget fears of today cripple the science of tomorrow.