TAG: Galaxies
May 26, 2010– 0

Wolfram|Alpha’s coverage of the universe continues to grow. We have now added a large collection of observed supernovae in the universe to our ever-expanding compendium of astronomical knowledge.

What exactly is a supernova? It’s a catastrophic event in the life of a star.

The full details are very complex, but basically supernovae are the visible signs of the deaths of stars more massive than the Sun. As with all other stars, massive stars spend most of their lives fusing hydrogen gas into helium in their cores. This results in a buildup of “ash” (end product of fusion reactions) in the core that eventually chokes off the hydrogen fuel from the hottest area of the core. With no new fuel, there is less energy being produced to counter the gravity trying to squeeze the star’s huge mass more tightly together. The result is that the star’s core begins to collapse as gravity overtakes the outward pressure. This results in heating the core—eventually enough that the ash can begin fusing into heavier molecules, initially carbon and oxygen. The cycle repeats, each time beginning and ending with different products and creating the next fuel source. Eventually, the core contains iron. Iron cannot liberate energy from fusion, so at this point, energy generation in the core suddenly stops, and the full mass of the star comes crashing down and a shock wave rips the star apart. This explosion is called a Type II supernova and results in the formation of a neutron star (or more rarely a black hole). More »

May 20, 2010– 4

Sitting in your office watching and cursing the rainy outdoors, have you ever wondered what the weather beyond our protective atmosphere is like?

Yes, there is weather even in the empty space above Earth’s atmosphere. Space weather typically refers to phenomena resulting from solar activity. It’s also one of the latest content additions to Wolfram|Alpha. Space weather includes things like sunspots, solar X-rays, and solar wind, as well as their effects on the Earth itself (e.g. aurorae, radio communication blackouts, and in extreme cases power outages).

The Sun has an 11-year cycle. Every 11 years, the number of sunspots rises to a peak and then falls to a minimum. Sunspots result from areas of strong magnetic fields on the Sun that cool the surrounding gas and makes the gas appear darker. When these tangled magnetic fields reconnect, the plasma carried along with it can be flung with huge amounts of energy away from the Sun. If it is directed toward Earth, we may observe a number of effects. Depending on how the magnetic field is oriented, it may bounce off the Earth’s magnetic field with no effect. If oriented the other way, the plasma funnels down the Earth’s magnetic field lines until it encounters the atmosphere, causing it to glow. This glowing is known as the aurora borealis in the northern hemisphere and the aurora australis in the southern hemisphere.

The sunspot cycle likely plays a role in Earth’s global climate. The exact nature of its effect is still a hot area of active research. More sunspots mean more energy is likely to be absorbed by the Earth from the Sun. Fewer sunspots mean less energy and potentially a cooler climate. Between 1645 and 1715, sunspots on the Sun nearly vanished. During the same period, called the Maunder minimum, Europe experienced colder-than-average temperatures, contributing to what some have called “the little ice age”. Data for sunspots goes back much further than most other space weather data. Most other phenomena could not be measured until the advent of artificial satellites, and many much more recently than that.

In 1859, the first and most powerful solar flare ever observed occurred, known as the Carrington event. Within a couple of days of the flare, the Earth’s magnetic field oscillated wildly from the magnetized plasma thrown toward us. The magnetic field lines of the Earth bounced back and forth across telegraph wires, causing massive failures and even melted wires from the induced currents. An event of that strength today would cause untold havoc, as we are far more dependent on telecommunications via both satellites and land-based wires. More »

December 18, 2009– 4

When astronomers observe a distant object in the universe, how do they know how far away it is? One method involves the object’s redshift.

What is redshift? It is a shift in the wavelength of electromagnetic radiation toward the longer-wavelength (red) end of the spectrum. Astronomers measure redshift by looking at the spectrum of light from a given distant object.

Type “redshift 6.3” into Wolfram|Alpha.

Wolfram|Alpha computes data for a redshift 6.3

The assumption pod at the top indicates that Wolfram|Alpha has interpreted our “redshift” query as “cosmological redshift”. The “more” menu there lets you access alternate interpretations. More »

August 28, 2009– 4

The amount of activity that takes place here on planet Earth is at times unfathomable. But it’s the merest drop in the bucket in comparison to the boundless amounts of activity in our universe—Earth is merely one planet within the Milky Way Galaxy. Most deep-sky objects cannot be seen by the naked eye, but observers looking through a telescope are treated to views of colorful clusters of light and fuzzy clouds of gas in the sky. Here we’ll demonstrate ways Wolfram|Alpha can help you find deep-sky objects such as galaxies, nebulae, and star clusters—our universe has about 100 billion member galaxies, and with so many, it’s nice to have a place to start.

Querying “galaxies” in Wolfram|Alpha will produce a list of some of the brightest as seen from Earth. Let’s compare the properties of the galaxies NGC 7544 and the nearby M 83 (well, only 15.78 million light years away). Wolfram|Alpha provides information including their approximate distance from Earth, Hubble type, apparent magnitude, equatorial position, and position in the sky and visibility from your current location. Keep in mind that object distances may not be available for all objects; one of the great mysteries of astronomy is that distance is notoriously difficult to determine except in special cases. More »