Does The Moon Really Orbit The Earth?

According to Newton’s law of gravitation, the sun should “pull” way harder on the moon than the Earth does. So does the moon actually orbit the Earth? Why?

 

How do Planetary Flybys Work?

NASA uses fly bys or gravity assists all the time, but what's actually going on? For more, including some links to mission proposals that take advantage of fly bys, check out my latest post over on Vintage Space.

 Title image via NASA. Music "The Coup" by AudioQuattro from Music Loops. Cheers to Jonathon Smith and JPL for the video.

For more Vintage Space, add me on Facebook, Google+, and Twitter as @astVintageSpace. And subscribe to Vintage Space on Popular Science for regular blog updates.

Amy Shira Teitel

 

The Big Bang Theory

The Big Bang is the name of the most respected theory of the creation of the universe. Basically, the theory says that the universe was once smaller and denser and has been expending for eons. One common misconception is that the Big Bang theory says something about the instant that set the expansion into motion, however this isn’t true. In this video, Fermilab’s Dr. Don Lincoln tells about the Big Bang theory and sketches some speculative ideas about what caused the universe to come into existence.

 

Where did we come from?

Nuclear chemist Cole Pruitt explains what Nuclear Pasta is and how we were all born inside the core of giant stars.

 

How do we study the stars? - Yuan-Sen Ting

Our best technology can send men to the Moon and probes to the edge of our solar system, but these distances are vanishingly small compared to the size of the universe. How then can we learn about the galaxies beyond our own? Yuan-Sen Ting takes us into deep space to show how astronomers study the stars beyond our reach.

 Lesson by Yuan-Sen Ting, animation by Kozmonot Animation Studio.

 

How Do We Measure the Distance of Stars?

The Bad Astronomer Phil Plait teaches Hank how to measure the distance to the stars.

 

ScienceCasts: Evidence for Supernovas Near Earth

A NASA sounding rocket has confirmed that the solar system is inside an ancient supernova remnant. Life on Earth survived despite the nearby blasts.

 

NASA | Late Summer M5 Solar Flare

On Aug. 24, 2014, the sun emitted a mid-level solar flare, peaking at 8:16 a.m. EDT. NASA's Solar Dynamics Observatory and STEREO captured images of the flare, which erupted on the left side of the sun. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel.

To see how this event may affect Earth, please visit NOAA's Space Weather Prediction Center at http://spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings. This flare is classified as an M5 flare. M-class flares are ten times less powerful than the most intense flares, called X-class flares.

 

How to Find an Exoplanet

These planets are too far away for direct observation.

 

ScienceCasts: Sizing up an Exoplanet

Astronomers are not only discovering planets around distant suns, they are also starting to measure those worlds with astonishing precision. The diameter of a super-Earth named Kepler 93B is now known to within an accuracy of 148 miles.

 

NASA | Neutron Stars Rip Each Other Apart to Form Black Hole

This supercomputer simulation shows one of the most violent events in the universe: a pair of neutron stars colliding, merging and forming a black hole. A neutron star is the compressed core left behind when a star born with between eight and 30 times the sun's mass explodes as a supernova. Neutron stars pack about 1.5 times the mass of the sun — equivalent to about half a million Earths — into a ball just 12 miles (20 km) across.

As the simulation begins, we view an unequally matched pair of neutron stars weighing 1.4 and 1.7 solar masses. They are separated by only about 11 miles, slightly less distance than their own diameters. Redder colors show regions of progressively lower density.

As the stars spiral toward each other, intense tides begin to deform them, possibly cracking their crusts. Neutron stars possess incredible density, but their surfaces are comparatively thin, with densities about a million times greater than gold. Their interiors crush matter to a much greater degree densities rise by 100 million times in their centers. To begin to imagine such mind-boggling densities, consider that a cubic centimeter of neutron star matter outweighs Mount Everest.

By 7 milliseconds, tidal forces overwhelm and shatter the lesser star. Its superdense contents erupt into the system and curl a spiral arm of incredibly hot material. At 13 milliseconds, the more massive star has accumulated too much mass to support it against gravity and collapses, and a new black hole is born. The black hole's event horizon — its point of no return — is shown by the gray sphere. While most of the matter from both neutron stars will fall into the black hole, some of the less dense, faster moving matter manages to orbit around it, quickly forming a large and rapidly rotating torus. This torus extends for about 124 miles (200 km) and contains the equivalent of 1/5th the mass of our sun. The entire simulation covers only 20 milliseconds.

Scientists think neutron star mergers like this produce short gamma-ray bursts (GRBs). Short GRBs last less than two seconds yet unleash as much energy as all the stars in our galaxy produce over one year.

The rapidly fading afterglow of these explosions presents a challenge to astronomers. A key element in understanding GRBs is getting instruments on large ground-based telescopes to capture afterglows as soon as possible after the burst. The rapid notification and accurate positions provided by NASA's Swift mission creates a vibrant synergy with ground-based observatories that has led to dramatically improved understanding of GRBs, especially for short bursts.

 

A virtual Universe

Scientists at MIT have traced 13 billion years of galaxy evolution, from shortly after the Big Bang to the present day. Their simulation, named Illustris, captures both the massive scale of the Universe and the intriguing variety of galaxies -- something previous modelers have struggled to do. It produces a Universe that looks remarkably similar to what we see through our telescopes, giving us greater confidence in our understanding of the Universe, from the laws of physics to our theories about galaxy formation.

 

What is a pulsar?

In less than 100 seconds, Tim O'Brien of the University of Manchester in the UK provides a fly-by tour of pulsar science. When the first pulsar signal was detected in the 1960s, for a short time it was referred to as "little green man 1" because the regular pulsing appeared to be a message from aliens. However, it did not take long for astronomers to figure out that these signals come from rapidly rotating neutron stars, which beam radiation from their magnetic poles.

 

Big Mysteries: Dark Energy

Scientists were shocked in 1998 when the expansion of the universe wasn't slowing down as expected by our best understanding of gravity at the time; the expansion was speeding up! That observation is just mind blowing, and yet it is true. In order to explain the data, physicists had to resurrect an abandoned idea of Einstein's now called dark energy. In this video, Fermilab's Dr. Don Lincoln tells us a little about the observations that led to the hypothesis of dark energy and what is the status of current research on the subject.

 

A Polarizing Discovery About the Big Bang!

ScienceCasts: A Sudden Multiplication of Planets

This week, NASA announced a breakthrough addition to the catalog of new planets. Researchers using Kepler have confirmed 715 new worlds, almost quadrupling the number of planets previously confirmed by the planet-hunting spacecraft. Some of the new worlds are similar in size to Earth and orbit in the habitable zone of their parent stars.

 

What we can learn from galaxies far, far away - Henry Lin

In a fun, excited talk, teenager Henry Lin looks at something unexpected in the sky: galaxy clusters. By studying the properties of the universe's largest pieces, says the Intel Science Fair winner, we can learn quite a lot about our own world and galaxy.

 

NASA | Jewel Box Sun

This video of the sun based on data from NASA's Solar Dynamics Observatory, or SDO, shows the wide range of wavelengths -- invisible to the naked eye -- that the telescope can view. SDO converts the wavelengths into an image humans can see, and the light is colorized into a rainbow of colors.

As the colors sweep around the sun in the movie, viewers should note how different the same area of the sun appears. This happens because each wavelength of light represents solar material at specific temperatures. Different wavelengths convey information about different components of the sun's surface and atmosphere, so scientists use them to paint a full picture of our constantly changing and varying star.

Yellow light of 5800 Angstroms, for example, generally emanates from material of about 10,000 degrees F (5700 degrees C), which represents the surface of the sun. Extreme ultraviolet light of 94 Angstroms, which is typically colorized in green in SDO images, comes from atoms that are about 11 million degrees F (6,300,000 degrees C) and is a good wavelength for looking at solar flares, which can reach such high temperatures. By examining pictures of the sun in a variety of wavelengths -- as is done not only by SDO, but also by NASA's Interface Region Imaging Spectrograph, NASA's Solar Terrestrial Relations Observatory and the European Space Agency/NASA Solar and Heliospheric Observatory -- scientists can track how particles and heat move through the sun's atmosphere.

 The 2.9 minute movie was created by NASA's Scientific Visualization Studio or SVS at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and is available at the SVS website: http://svs.gsfc.nasa.gov/goto?11385

 

The death of the universe - Renée Hlozek

The shape, contents and future of the universe are all intricately related. We know that it's mostly flat; we know that it's made up of baryonic matter (like stars and planets), but mostly dark matter and dark energy; and we know that it's expanding constantly, so that all stars will eventually burn out into a cold nothingness. Renée Hlozek expands on the beauty of this dark ending.

 Lesson by Renée Hlozek, animation by Giant Animation Studios.

 

Big Questions: Dark Matter

Carl Sagan's oft-quoted statement that there are "billions and billions" of stars in the cosmos gives an idea of just how much "stuff" is in the universe. However scientists now think that in addition to the type of matter with which we are familiar, there is another kind of matter out there. This new kind of matter is called "dark matter" and there seems to be five times as much as ordinary matter. Dark matter interacts only with gravity, thus light simply zips right by it. Scientists are searching through their data, trying to prove that the dark matter idea is real. Fermilab's Dr. Don Lincoln tells us why we think this seemingly-crazy idea might not be so crazy after all.