Department of Astronomy
Department of Astronomy

Ask an Astronomer

 

 

While we can't claim to know everything about the universe, we can answer some commonly asked questions about astronomy.

Please note that this page is not intended to provide any financial advice or endorse any specific company, organization, or institution. It is intended as a guide, and we encourage you to explore topics.

Meteorites

The University of Virginia does not verify meteorites. If you are looking to see if what you found is a meteorite, consider reaching out to a geologist or an expert in rocks and minerals.

Meteorites are meteoroids that have survived the journey through the atmosphere and have landed on Earth.  At first glance, they may look like any other rock. Like rocks, meteorites are made of minerals, some of which can be found here on Earth. They can also be made of materials not found on Earth. Their makeup can provide clues to where the meteorite came from. Most are stony-iron and iron.

A meteorite. Photo courtesy of Oxford Museum of Natural History

I think I found a meteorite!

While meteorites can fall anywhere on Earth, finding one is incredibly rare. Most land in oceans and are lost to discovery. Those that have been found are found mainly in Antarctica, and this is for a few reasons. First, there is no vegetation to camouflage them. They are easier to spot against the snow and ice. Second, glacial movement can help concentrate them in certain areas. Finally, the cold temperatures of the continent can help protect the meteorites from weathering, sometimes for thousands of years.

The physical characteristics of meteorites are as follows:

  1. Density: Meteorites are usually quite heavy for their size, since they contain metallic iron and dense minerals.
  2. Magnetic: Since most meteorites contain metallic iron, a magnet will often stick to them. For “stony” meteorites, a magnet might not stick, but if you hang the magnet by a string, it will be attracted.
  3. Unusual shape: iron-nickel meteorites are rarely rounded. Instead, they have an irregular shape with unusual pits like finger prints in their surface called “regmaglypts.”
  4. Fusion crust: stony meteorites typically have a thin crust on their surface where it melted as it passed through the atmosphere.

Meteorites do NOT have:

  1. Light-colored crystals: Quartz is a common, light-colored crystal in Earth’s crust, but it is not found on other bodies in the solar system.
  2. Bubbles: volcanic rocks or metallic slag on Earth often have bubbles or vesicles in them, but meteorites do not.
  3. Streak: if you scratch a meteorite on an unglazed ceramic surface, it should not leave a streak. A dense rock that leaves a black or red streak probably contains the iron minerals magnetite or hematite, respectively, neither of which are typically found in meteorites.

Source: United States Geological Survey

The easiest test you can perform is seeing if your sample is magnetic. You can test this with a relatively strong refrigerator magnet. If it does not easily stick to the sample, you most likely do not have a meteorite. However, even if your sample is magnetic, you may have found slag. 

  • Slag is a by-product of steel making, and is produced during the separation of the molten steel from impurities in steel-making furnaces. It starts out as a molten liquid, then oxidizes and solidifies when cooled.

Slag can sometimes be found in Virginia's waterways as a relic of railroad and other construction. It can easily be mistaken as a meteorite, since both items are magnetic and have an unusual shape. 

Image courtesy of Washington University in St. Louis Earth, Environmental, and Planetary Sciences

As stated above, the University of Virginia does not verify meteorites. Consider reaching out to a geologist or an expert on rocks and minerals to verify your sample.

Another great resource is the Washington University in St. Louis Earth, Environmental, and Planetary Sciences page on meteorites.

Stargazing

What's in the sky tonight?

Your view of the cosmos depends on your position on Earth. The United States is in the northern hemisphere, so be sure to look at sky maps and charts that are for the northern hemisphere. In addition, the positions of objects change over time. Your chart should match the current month or season.

A great resource is skymaps.com. They provide free sky maps available to download monthly. 

Additionally, in-the-sky.org provides a calendar view of what you can expect to see. You can even change how you will be looking up (visible to the naked eye, binoculars, telescopes, etc.)

 

Where should I go stargazing around Charlottesville?

The City of Charlottesville and areas of Albemarle County have grown significantly over the past few decades, which has caused an increase in light pollution. This makes it more difficult to stargaze in densely populated areas.

  • Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It can be caused by cities, outdoor lights, streetlights, parking lots, vehicles, and other objects or structures that produce light at night. The phenomenon impacts an individual's view of the night sky, among other things.
  • To learn more about light pollution, visit the Dark Sky International website.

The best places to stargaze are places with little light pollution and higher elevations. Big Meadows at Shenandoah National Park is a popular place for stargazing in the area, since it sits on top of a mountain and is away from most sources of light pollution. They frequently host events for night sky viewing, which you can learn more about on their webpage.

The Charlottesville Astronomical Society also hosts events for skygazing. Visit their calendar page for a full list of their upcoming events.

Please do not go to the McCormick Observatory to stargaze. The grounds are closed to visitors on evenings that are not Public Nights, and entry onto the grounds outside of these times is considered trespassing. If you would like to visit the Observatory, you may learn more on the Public Night webpage. 

Additionally, be mindful if you decide to explore rural areas to stargaze. Do not trespass on private property. 

I think I saw a UFO!

A UFO, or unidentified flying object, is a blanket term for something seen in the sky that we do not have a clear explanation for. Science fiction stories about UFOs can be entertaining, but nearly everything seen in the night sky has an explanation. 

Some of the most common objects mistaken for UFOs include:

  • Military aircraft: Often, military aircraft are top secret, so it's hard to figure out if you truly saw one. However, if you live near a military base, chances are good that you may see one in the night sky.
  • Meteors: When meteoroids fall to earth, they burn up in Earth's atmosphere, becoming meteorites. They can create streaks of light in the sky as they fall to Earth.
  • Lens flares: When light bounces off the lens of a camera or a phone camera, a flare can be created, distorting what is seen.
  • The International Space Station: The station moves across the sky very quickly, and it can appear to be something otherworldly. You can track the movement of the ISS on NASA's website.
  • High-altitude or weather balloons
  • Airplanes
  • Space debris: While not usually visible from space, they can create colorful streaks of light across the sky if they fall to Earth.
  • Satellites: There are several thousand satellites orbiting Earth right now. There's a good chance that you might have spotted one. You can track the motion of different satellites on various websites, including SatelliteXplorer.
  • Drones: These have become increasingly popular and accessible to the average consumer over the past few years, and they can often have bizarre flight patterns. Many also have blinking lights.

What kind of telescope should I get for night sky viewing?

There are many options out there for personal use telescopes. The Department cannot make a brand or model recommendation, however there are some key things you should look out for if you are considering a telescope for yourself or the astronomer in your life.

Below are some guides that might be helpful when considering your telescope purchase:

Additional Resources

 

We encourage continued exploration of the cosmos! Check out the resources below to help you along the way