Category Archives: gravity

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

So you think you can orbit?

Pluto & Charon do the perpendicular binary hip-hop

Pluto & Charon do the perpendicular binary hip-hop

Pluto and Charon dance it off in the intergalactic smash hit “So you think you can orbit?”  Can their perpendicular orbit help them win it all?

Listen here [2:02m]:

Download here [1.9 Mb]: ftp://space.mit.edu/pub/ajb/radiopio/astrofacts_090813_soyouthinkyoucanorbit.mp3

What’s the facts:

Pluto, the second-largest known dwarf planet in the Solar System (after Eris), and its largest moon, Charon, are sometimes treated as a binary system, because the center of their orbit does not lie within either body (Charon is about half as big and 1/7th as massive as Pluto).   Indeed, before its re-classification, Pluto and Charon were the closest thing to a double planet known.  The orbit of Pluto and Charon is also special in that it is nearly perpendicular to the plane of their mutual orbit around the Sun, like a record rolling on its side (Uranus and its moons are tilted over in a similar way).  As such, the Pluto-Charon orbit can be seen either face-on – like a clock – or edge-on – like a thrown frisbee – during its 248-year trek around the Sun. Between 1985 and 1990 the orbit was aligned edge-on so that the two bodies repeatedly passed in front of each other, or eclipsed.  These eclipses allowed astronomers to measure both the sizes of Pluto and Charon as well as make a rough map of Pluto’s surface features.  Finally, Pluto and Charon are the only planet-moon pair whose orbit and rotations are mutual synchronized; that is, they both face the same face to each other all the time. This makes Pluto and Charon excellent partners as the dance their way through space!

Original air date 13 August 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.

You Need Dark Matter!

DARK MATTER helped bring the bullet cluster together!

DARK MATTER helped bring the bullet cluster together!

Are you a flabby galaxy, tired of being pushed around by the bigger galaxies in your local group? Need to bulk up in a hurry so you can be gravitationally attractive? Then you need DARK MATTER! Listen to our infomerical to find out how dark matter has helped galaxies like the Milky Way and M33, and what it can do for you.

Listen here [6:12m]:

What’s the facts:

Dark matter is a mysterious substance that we cannot see, touch, smell, hear, or taste (although it might not taste so bad).  Yet there is about 6 times more of it in the Universe than normal matter,  stuff like protons, electons, and neutrons that the stars, planets, and people are made of.  If we can’t see it, how do we know dark matter is out there?  Well, dark matter still has a gravitational force associated with it, and it is that “extra attraction” that reveals its existence.  The motion of galaxies in clusters and the orbits of stars around the centers of galaxies (including our own) both reveal the presence of dark matter.  Perhaps more spectacularly, a large amout of dark matter – say, associated with a whole cluster of galaxies – acts as a gravitational lens, focusing and warping light from galaxies behind the cluster like a fun house mirror (for an interesting example, see this picture of Abell 2218).  Despite not being able to see dark matter, scientists know quite a bit about its properties – that its probably not just “dim” normal matter (like neutrinos or brown dwarfs); that it is mostly “cold” (not moving close to the speed of light); that it interacts very weakly with regular matter (as illustrated with the Bullet Cluster collision); and that it is distributed over large length scales like the size of  a galaxy, as opposed to the size of a planet (sorry, no pulling dark matter tricks on your little brother at home).  Because it is makes up so much of the known Universe, there are many experiments now underway to try to detect dark matter through their infrequent collisions with other regular matter particles.  Hopefully, within the next few years we may have our first detection of the stuff that makes up most of the mass in the Universe!

Original air date 23 June 2009.