miércoles, 17 de diciembre de 2014

What was the Star of Bethlehem?

Do you know why there is a star on top of the Christmas tree or in the Nativity scene? The Gospel of Matthew says that magi from distant places saw a star in the sky that revealed them the birth of Jesus and led them to Bethlehem.
Did the star really exist? We don't know, but in that time, there were some interesting phenomena in the sky. Could one of them have been the Star of Behtlehem?

A comet?
A comet is an object with a long tail that moves through the sky. The most famous is Halley's comet. In the Adoration of the Magi, the painter Giotto drew this comet as the star as he had observed it in 1301. But comet Halley came close to the Earth in 12 b.C., too soon to be the star of Bethlehem. 

And what about planets?
There were two planetary conjunctions around the time of Jesus' birth: a triple conjunction of Jupiter and Saturn in 7 b.C. and a conjunction of Mars, Jupiter and Saturn in 6 b. C. Both of them over the constellation of Pisces. Jupiter was considered the star of royalty, Saturn the star of the Mesopotamian deity who protected Israel and Pisces was the constellation associated to Jewish people.
A big explosion in the sky?
Chinese astronomers watched a new star in 5 b.C.  visible for over 70 days. Probably it was a nova. This is a big explosion on a white dwarf of a binary system when it takes hydrogen from the other star.
Another possibility is a supernova. This is the largest explosion that takes place in space. It happens when a star dies and it may shine with the brightness of millions suns. But no supernova remnant, as a nebula, is known from that time. 

And you? What do you think about the Star?
Here you have some hypothesis about the Star of Bethlehem. Buth there are others. In your opinion, which is the most likely hypothesis? Can you find another one? Please, write your opinions as comment. And have merry Christmas and a happy new year.

lunes, 10 de noviembre de 2014

The best answer to a difficult question

Of course. I know that it was a very difficult question: Can you find any planet in your constellation?. But now, nothing is impossible if you work hard; and you have books, Internet... So, I want to post here the best answer to our difficult questions and his author:  

The orbits of all planets are in a plane. For this reason the planets are on a line in the sky. this line is the ecliptic. You can see planets in a contelations only if the ecliptic pass for this constelations. I drawing the ecliptic in Stellarium and I see what constelations pass for the ecliptic. Aries, Taurus, almost Orion, Gemini, Cancer, Pisces, almost Cetus, Aquarius, Leo, almost Sextans, Virgo, Libra, Scorpius (my constelation), Ophiuchus, Sagittarius, Capricornus. Venus pass through Scorpius on 19 September 2014. Mercury aproximately 30 November 2014. Saturn aproximately 25 January 2015. Jupiter aproximately 26 November 2018 with the Sun and Mercury. Uranus aproximately 22 January of 2066. And Neptune in year 2136. I see this in Stellarium.
Bruno Otero Galadí, 1º ESO B.

domingo, 2 de noviembre de 2014

Stars, planets and moons dressed up as Halloween monsters!!!

Thank you very much for your drawings. Here you have only a selection of all the drawings you have presented. I invite you to see our notice-board in the the hall of the school and the notice-boards in your classrooms. If your picture is not in this blog, please write a comment with a description of your drawing.
This is Death City Moon. Some people says that in dark nights you can hear her laughting. We know that her eye is a big crater, but what is her smile? Inma Ruiz Löpez, 1º ESO B.
My draw is the Sun. This is a devil. The spider is Mercury and the ghost is a galaxy. I like it because is the good costume of Halloween. The Sun has got a trident. Andrea García Manzano, 1º ESO A.
I choose Venus to dress it of Frankenstein, because I like it very much. Marta Castillo Villén, 1º ESO A.
Mu planets are Earth and Moon. I like the zombie because is nice, and the vampire is one animal because scary. Gema Gómez Salmerón, 1º ESO A. 
The Moon is a murderer and the Earth is a pumpkin. Esther Mesa Medina, 1º ESO B.

The Solar System is a star (Sun), 8 planets and satellites. Sara Muñoz Bolaños, 1º ESO B.
Phantom is Super-Saturn and Sun is ready to scare on Halloween pumpkin from space. Iara Rodríguez Texeira, 1º ESO B.
Alejandro Valero Rodríguez, 1º ESO B.

jueves, 23 de octubre de 2014

About Halloween

Next Friday is Halloween. Perhaps you don't know that Halloween's origin is astronomical. Since the fifth century B.C. Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox and a solstice. Nowadays, Halloween modern celebration retains historic roots in dressing up to scare away the spirit of the dead. This is the reason why lot of people wear fancy dresses that day.
And if we look at the sky with big telescopes we can see pictures like this one I show you below. The stars seems to be dressed up there. Can you see in this picture a witch head? Her eye, nose, mouth and chin? Sure. This is the reason why this cloud is known as the Witch Head Nebula.
But please, come back to the Earth.Will you be wearing a Halloween costume next Friday? We would  like to know. Please, write a comment. 
By the way, we are learning about Astronomy in our clases now. So, why don't you dress your favourite planet, moon, comet, galaxy or nebula up as a Halloween monster? I will put in this blog the best drawings.
Have a Happy Halloween.

The Witch Head Nebula (APOD, NASA)

viernes, 17 de octubre de 2014

Can you see any planet in your constellation?

In our last class, we were talking about the Solar System and its bodies: planets, satellites, comets and asteroids. As I told you, ancient Greek gave the planets this name as they noticed how these bodies travel through the night sky. So, if you look at the sky night after night it is possible that you recognize a planet as a small point of light that changes its position between constellations (see the picture below). Every one of you have chosen your constellation and we are going to learn lots of things about them, about their galaxies, nebulae... But, what about planets? Is possible to see planets in every constellation? Could you see any planet in your constellation?  Those are our first questions.
But if you think that you can see planets only in some constellations... Which ones are these constellations? And why you can watch planets only in those regions of the sky? 
They are not easy questions, but I am sure that all of you are very clever. Please, send your answers as a comment. You will have extra points.
And here you have a picture from APOD. It's Saturn moving through the sky from August 2005 to September 2008.

Three years of Saturn. Nasa APOD, Peter Wienerroither