Category Archives: space and time

Making Friends with the Night Sky: Women and the Moon

Our earliest calendar - linking the lunar cycle with the menstruation cycle

Maui astronomer Harriet Witt describes the connection between women and the Moon.

Listen here [2:41m]:

Download here [2.5 Mb]: ftp://space.mit.edu/pub/ajb/radiopio/astrofacts_090804_mfns-womenandmoon.mp3

What’s the facts:

The earliest astronomers may have been women, who discovered that the cycle of the Moon was synchronized with their menstrual cycle.  Having an external cue for this internal cycle would have allowed women to time the birth of their children and perhaps help regulate the population of their tribe or clan in an environment with limited resources.

Our earliest evidence of the connection between the Moon cycle and menstruation cycle – indeed, our earliest evidence of the practice of astronomy – is found on a reindeer bone over 20,000 years old, called the Ishango Bone.  This bone is also believed to be early evidence of the beginning of mathematical thought.  The Ishango bone is one of our first calendars (other ancient calendars also traced the cycles of the Moon).

Original air date 4 August 2009.

Making Friends with the Night Sky: The Full Moon

Lunar eclipses can occur during the full moon period

Lunar eclipses can occur during the full moon period

Maui astronomer Harriet Witt describes our full moon, and how the alignment of the Sun, Earth and Moon – syzygy – can affect the planet.

Listen here [3:08m]:

Download here [2.9 Mb]: ftp://space.mit.edu/pub/ajb/radiopio/astrofacts_090801_mfns-fullmoon.mp3

What’s the facts:

Halfway through our lunar cycle, the Moon and the Sun are now on opposite sides of the Earth, so we see a fully sun-lit full Moon.  At this time, the Moon rises as the Sun sets, and the Sun rises as the Moon sets.  This alignment of Sun, Earth and Moon is called syzygy (pronounced “SI-zi-gee“) and occurs during both new and full moon.  This alignment magnifies the ocean tides on Earth (both the Sun and the Moon cause tides through gravitational force), and the full moon is a time when lunar eclipses can occur, about once or twice a year.   Imagine standing on the Moon at this moment; you would see a “new Earth”, or the dark side of the Earth, up in the sky.  Similarly, you would see a “full Earth” during the period of new moon.   In many ways, full moon is a period of opposition.  It is also a period of celebration, with many holidays occurring during full moon in tradiational cultures, such as the Chinese Lantern Festival, the Hebrew Passover, and the Muslim Shab-e-Bara’at.  The bright night also inspires full moon parties.   Have fun celebrating our closest celestial neighbor!

This Astrofact is dedicated to Mahina, our four-legged full moon.

Original air date 1 August 2009.

Making Friends with the Night Sky: The Waning Crescent

The waning crescent appears on the left in the Northern hemisphere, and the right in the Southern hemisphere

The waning crescent appears on the left in the Northern hemisphere, and the on right in the Southern hemisphere

Maui astronomer Harriet Witt describes the “old” waning crescent Moon.

Listen here [3:30m]:

Download here [3.2 Mb]: ftp://space.mit.edu/pub/ajb/radiopio/astrofacts_090813_mfns-wanningcrescent.mp3

What’s the facts:

The waning crescent, or “old moon”, can be seen shortly before dawn, a thin sliver that rises ahead of the Sun.  You have a short period to catch it; after the Sun rises, the thin crescent is hard to see in the bright glare of day.  The waning crescent occurs toward the end of the new Moon to new Moon cycle, a siderial period of  27 1/2 days if you measure the Moon’s position relative to the stars, or a synodic period of 29 1/2 days if you measure relative to Sun.  The difference is due to the Earth’s motion around the Sun.  During a “moonth” the Earth has traveled about 1/13th of its yearly orbit (at a rate of 1.3 million miles per day).  So from our point of view, the Sun has moved to a different part of the sky relative to the stars – by about 28 degrees – over the lunar cycle.  Every month brings a new perspective!

Original air date 13 August 2009.

Spacetime!

Spacetime will suck up all your time...and space!

Spacetime will suck up all your time...and space!

Charae and Bryce take us on a trip into spacetime, with a song about everything they’ve learned from Astrofacts, to the tune of Rihanna’s Disturbia.

Listen here [2:50m]:

Download here [2.7 Mb]: ftp://space.mit.edu/pub/ajb/radiopio/astrofacts_090730_spacetime.mp3

What’s the Facts:

Charae & Bryce have put together a song that’s rich in astrofacts. Let’s break down the lyrics to see what they will encounter on their trip into spacetime.

Lyrics:

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune, Uranus, Plut-
Whao! Hold up. Not Pluto.
What?!? Not Pluto?
Yeah, Not Pluto.
I’m goin’ crazy now

Here’s our planets of the Solar System, up to Pluto, which has been “reclassified” as a dwarf planet.  Pluto might be feeling a bit down about it, and plenty of people are not happy either!  By the way, Neptune comes after Uranus, our mistake!

To the moon in this ship,
We’re gonna get it started,
Fuel tanks filled to the rim,
Discover the uncharted,
Breaking through atmospheres,
It’s not for the fainthearted,
We’re gonna go into space, yeah

Want to go into space?  Be prepared for an explosive ride!  You only need enough force to overcome Earth’s gravitational pull to go toward space – which you can do briefly by jumping!  But to sustain the upward trajectory requires lots of fuel and thrust.  The rockets that carry the Space Shuttle have a combined thrust of 13 million Newtons – 20,000 times the force you exert when jumping – to lift the 4.5 million pounds (2 million kg) that hold 7 lucky astronauts!

It’s real hot on the Sun,
Forgot my sunscreen,

It’s definitely hot on the Sun – 9,800 degrees Farenheit! That’s so hot that everything is essentially evaporized on the surface, and atoms are even stripped of their electrons to form a 4th state of matter called plasma.

The day’s long here on Mars,
I need some caffeine,

A day on Mars take 24 hours, 39 minutes, and 35 seconds – about 3% longer than that of Earth.  So it’ a little longer, but you’ll adjust.

2.9 times 10 to the 13
Miles a minute, I’m carsick.

That’s a pretty big number, and  one would hazard to guess that it’s the speed of light.  However, the speed of light is only about 11 million miles per minute.  290,000,000,000,000 miles is about 5 light-years, a little further than the nearest star to the Sun, Alpha Centauri.  If you could do that in a minute, you would certainly be carsick!

We’re in great heights,
In one of Saturn’s rings, yeah
You ain’t go bling like mine,
Meteors made for kings,
We watch the stars shine,
From Polaris to Betelgeuse,
The universe is mine.

Some of the most beautiful things in our Universe! Saturn’s rings are definite bling, comprised of small particles of water ice and dust that are extremely reflective – that’s why Saturn it so bright despite being further from the Sun than JupiterMeteors are of course another dazzling night sky event, while Polaris (the North Star, in the constellation Ursa Minor, or Little Bear) and Betelgeuse (in Orion’s armpit!) are two of the brightest stars in the sky.

We’re all in Space-time,
Two words in one continuum,
Space-time,
1, 2, 3, 4 Dimensions,
Your mind’s in Space-time
Beyond comprehension,
Space-time, Space-time.

Space-time is that idea of three-dimensional space (length, width and height) combined with one-dimensional time as the “framework” of the Universe.  You probably already think this way, as in “I need to get to the third floor of the building on the corner of Main and 1st Avenue at 3pm”.  These dimensions appear to be completely separate in our slow, small-scale world, but when you travel close to the speed of light, or near a massive object like a black hole, Einstein’s theory of general relativity tells us that the continuum of space and time can get mixed up, resulting in some bizarre effects!

There’s a guy in the sky,
His names Orion,
Not a man, he’s made of stars,
Emitting carbon.

This refers to the massive giant star Betelgeuse in Orion, which is currently losing mass and size as it sheds its outer atmospheric layers.  It will eventually supernova, releasing many elements such as carbon into space.  It is all part of the cycle of life in the Universe, as the elements shed from stars like Betelgeuse when they die make their way to form other stars, planets and even people!

Acid rain falls,
It burns my eyeballs.
Venus lighting strobe light.

Remember our weather report from Venus?  Acid rain doesn’t quite make it the surface of the planet, but there are plenty of lightning strikes that might make the surface of Venus feel like a disco!

Lots of holes out in space,
They try to grab you,
They can creep up behind you and consume you,
Not even light can escape,
Nothing can breakthrough,
Spa-ghe-tti-fi-ca-tion.

Black holes are the massive remnants of stars that are so dense that nothing, not even light, can escape being swallowed up. If you’re not careful you’ll get pulled into it and never come out again.  And on the way in you’ll get stretched out long and slender, like spaghetti. That’s called spaghettification!

We’re in great heights,
In on of Saturn’s rings, yeah
You ain’t go bling like mine,
Meteors made for kings,
We watch the stars shine,
From Polaris to Betelgeuse,
The universe is mine.

We’re all in Space-time,
Two words in one continuum,
Space-time,
1, 2, 3, 4 Dimensions,
Your mind’s in Space-time,
Beyond comprehension,
Space-time, Space-time.

Lyrics by Charae and Bryce

Making Friends with the Night Sky: The Gibbous Moon

The moon entering its gibbous or hua phase

The moon entering its gibbous or hua phase

Maui astronomer Harriet Witt describes the waxing gibbous Moon.

Listen here [3:30m]:

Download here [2.6 Mb]: ftp://space.mit.edu/pub/ajb/radiopio/astrofacts_090801_mfns-gibbousmoon.mp3

What’s the facts:

Progressing from the first quarter, the Moon enters its waxing gibbous phase, on the way to full bright moon.  The Moon is showing more of its sunny side to us on Earth, and is taking on an egg-like shape.  That’s why Hawaiians call the gibbous phase (gibbous is derived from the latin word “gibbus”, or “hump”) the “hua” or “egg” phase.

Original air date 1 August 2009.

Making Friends with the Night Sky: Seeing stars that aren’t really there!

The red supergiant Antares

The red supergiant Antares in the constellation Scorpius.

Maui astronomer Harriet Witt describes one of the brightest stars in the constellation Scorpius, a distant red supergiant that may no longer exist.

Listen here [4:22m]:

Download here [4 Mb]: ftp://space.mit.edu/pub/ajb/radiopio/astrofacts_090714_mfns_notreallythere.mp3

What’s the facts:

In the center of the constellation Scorpius lies the bright red star Antares, the 16th brightest star in the night sky.  Antares is what is known as a red supergiant – its surface is cool and hugely extended, 800 times larger than the Sun. Indeed, if Antares were in the Solar System, it would engulf Mercury, Venus, Earth and Mars.  Stars become red supergiants at the end of their lifetimes, when they have exhausted most of their hydrogen fuel, and they on their way to a spectacular stellar death in the form of a supernova.  The red supergiant stage of a star’s lifetime is relatively short – a few hundred thousand to a million years.  In contrast, the light we see from this star was emitted 600 years ago, since it takes light 600 years to travel the 600 light-years of distance between us and Antares.  So it is possible that Antares is no longer there.  Ponder that while you’re enjoying your view of Scorpius tonight!

Original air date 30 June 2009.

Black Hole Showdown

A black hole wandering the universe. The lone wolf, they say.

A black hole wandering the universe. The lone wolf, they say.

Michael and Mason at the Pa’ia Youth and Cultural Center re-enact the scene of rogue black holes colliding in the Milky Way. If you thought the wild west was rough, you’ve got another thing coming. It can really get out of hand when trouble goes galactic!

Listen here [6:12m]:

What’s the facts:

A black hole is a region of space in which the gravitational field is so powerful that nothing, including light, can escape its pull.  Despite its “invisibility”, a black hole can reveal its presence through interaction with the matter it is sucking in, which produces high energy X-ray radiation. Newly merged black holes might be so jarred by the experience that they go “rogue,” careening into space on unexpected trajectories.   In fact, a recent study indicates that hundreds of these rogue black holes could exist in the Milky Way galaxy.  Better watch your back!

Original air date 19 July 2009.