The largest galaxy in the known universe

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Have you ever wondered which galaxy is the biggest galaxy in the known universe? Apparently, the galaxy known as IC 1101, located in the Virgo constellation (although Deep Astronomy states it is in the Serpens constellation in the video below), is a giant.

According to a 1990 New York Times article titled “Sighting of Largest Galaxy Hints Clues on the Clustering of Matter” –

The galaxy, embracing more than 100 trillion stars, is the extremely bright object at the center of a rich cluster of galaxies known as Abell 2029. Analysis of new telescopic images indicates that the object is a distinct galaxy more than six million light years in diameter, scientists report in the issue of the journal Science published today.

To get a sense of just how big IC 1101 is, here is an extract from an article on Futurism titled “The Largest Galaxy In the Known Universe: IC 1101“:

Just how large is it?  At its largest point, this galaxy extends about 2 million light-years from its core, and it has a mass of about 100-trillion stars. To give you some idea of what this means, the Milky Way is just 100,000 light-years in diameter. If our galaxy were to be replaced with this super-giant, it would swallow up both Magellanic clouds, the Andromeda galaxy, the Triangulum galaxy, and almost all the space in between. That is simply staggering.

Other resources:

Image credit: Galactic Pyrotechnics on Display (NASA, Chandra, 07/02/14) by NASA’s Marshall Flight Center, licensed CC BY NC 2.0

Have you met the tough Tardigrade?

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One of the strangest creatures I’ve come across (although not first-hand) is the Tardigrade. I first found about these tiny creatures on COSMOS: A Spacetime Odyssey (highly recommended) and they are really amazing. According to Wikipedia:

Tardigrades are notable for being perhaps the most durable of known organisms; they are able to survive extreme conditions that would be rapidly fatal to nearly all other known life forms. They can withstand temperature ranges from 1 K (−458 °F; −272 °C) to about 420 K (300 °F; 150 °C),[7] pressures about six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human, and the vacuum of outer space.[8] They can go without food or water for more than 30 years, drying out to the point where they are 3% or less water, only to rehydrate, forage, and reproduce.

National Geographic has a great article titled “5 Reasons Why The Tardigrade Is Nature’s Toughest Animal” which includes clips from COSMOS imagining what Tardigrades may look like in a waterdrop.

What fascinates me about them is that they are so resilient. I couldn’t help but imagine a possible future where humans are long gone and these little creatures become the dominant species on this planet after growing a little and developing technology.

SciShow has a video about them and why space agencies are so interested in them:

Other resources:

Image credit: “SEM image of Milnesium tardigradum in active state” by Schokraie E, Warnken U, Hotz-Wagenblatt A, Grohme MA, Hengherr S, et al. (2012) and submitted to Wikipedia. Licensed Creative Commons Attribution 2.5 Generic


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What are volcanos? There is quite a lot to know about volcanos and here is a starting point. According to an explanation in the Wikipedia volcanos portal:

A volcano is an opening, or rupture, in a planet’s surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. Violent explosive eruptions from such vents often produce craters or calderas and coat extensive areas in volcanic ash, while the lava from comparatively gentle effusive eruptions may eventually form large plains, cones or mountains.

Volcanoes are generally found where tectonic plates are pulled apart or come together. A mid-oceanic ridge, such as the Mid-Atlantic Ridge, hosts volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire contains many volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are not commonly created at transform boundaries, where two tectonic plates slide past one another.

We found a great playlist on National Geographic Kids about volcanos:

SciShow Kids also has a great video about volcanos for kids:

While we were looking up volcano information on Wikipedia, we saw some great explainer images. This one shows the anatomy of a volcano:

Volcano anatomy by MesserWolan, licensed CC BY SA 3.0
Volcano anatomy by MesserWolan, licensed CC BY SA 3.0

We also found this great view of an erupting volcano from the perspective of a satellite passing overhead:

Volcano eruptions can be pretty dangerous for aircraft too. You may remember the 2010 eruption of the Eyjafjallajökull volcano. National Geographic has an interesting report on the dangers of volcanic ash titled “Volcanic Ash Stops Europe Flights—Why Ash Is Dangerous“.

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According to Wikipedia:

A tsunami (plural: tsunamis or tsunami; from Japanese: 津波, lit. “harbor wave”;[1] English pronunciation: /tsˈnɑːmi/[2]) , also known as a seismic sea wave, is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions (including detonations of underwater nuclear devices), landslides, glacier calvings, meteorite impacts and other disturbances above or below water all have the potential to generate a tsunami.[3] Unlike normal ocean waves which are generated by wind or tides which are generated by the gravitational pull of the Moon and Sun, a tsunami is generated by the displacement of water.

I found great videos for the kids on YouTube (the challenge with teaching kids about tsunamis is that they are pretty devastating phenomena so I try to be careful about which videos I show them.

How tsunamis work – Alex Gendler

What is a Tsunami? Facts & Information | Mocomi Kids

I also found this great illustration of how an earthquake triggers a tsunami on Wikipedia (Link).

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Voyager craft heading into interstellar space

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My son asked me about space travel and we started talking about the Voyager 1 and 2 probes that were launched in the late 1970s and sent out to the outer planets. Those probes have begun their journey into interstellar space after passing out of our solar system.

NASA’s JPL (Jet Propulsion Labs) has great resources about the Voyager craft and a terrific YouTube playlist: