And the proportion of heavy water to light water in this comet matches Earth's ocean! Hartley 2 is from the Kuiper Belt. Herschel found that Hartley 2 has half as much heavy water as other comets studied so far. One is called "heavy water" and the other is called "light water." Our ocean has a certain proportion of heavy water to light water. There are two different types, or "isotopes" of water. This cloud is from the comet's ice boiling off its surface as it gets heated by the Sun.īut not all water is alike. Herschel can point toward a comet and analyze the water molecules in the fuzzy cloud of mist-or coma. Infrared is a kind of light we cannot see, but we may feel as heat. Herschel studied Comet Harley 2 in infrared light. It probably contains more than enough water to quench your thirst after eating a ton of peanuts!Ī telescope called the Herschel Space Observatory recently made an interesting discovery about a comet. Comets from either region sometimes go "off course." When they do, they sometimes end up in the inner solar system near Earth.Ĭomet Hartley 2 looks a little like a peanut. It is about 30 - 50 times farther away than the Kuiper Belt. Another region with even more comets is the Oort Cloud. The Kuiper Belt is a big region of icy objects, including comets, out beyond the orbit of Neptune. There are still lots of comets in the solar system. Asteroids contain some water too, so they may have contributed. It would take a lot of comets to fill the ocean! But comets could well have made a big contribution. It could be that comets made regular water deliveries to Earth. But that probably doesn't account for all the water.Ĭomets are mostly water ice. The rocky material that formed Earth in the first place contained some water. After Earth cooled down, the water would stop boiling off into space. At first, it was too hot to have an ocean. Where did the ocean come from?Įarth first formed about 4.5 billion years ago. There are many really big questions about Earth's history. Over the next several months, we will be listening to your feedback (link to alias) to see how viable this project may be in the long term.This artwork shows a rocky planet being bombarded by comets. Please help us evaluate the effectiveness of the proposed addition of wave detail to our Coastal Waters Forecast in real time. As such, the proposed Coastal Waters Forecasts maintains that variable, but also supplements it with wave detail as described above and provided in forecast. Significant Wave Height is a fundamental variable of the sea state that our customers are used to seeing, and also something very accessible from buoys to help gauge the current sea state and the accuracy of a forecast. The wave height values we currently provide are “ Significant Wave Heights”, which is the average height of the highest one third of all waves at a particular point or region in the ocean. 4-6 feet, etc) with no corresponding direction or period information. The point is, no two wave systems are created equal, any wave system present may be hazardous or of interest to different marine groups, and therefore we feel we should not ignore them.Īnimation from COMET showing multiple wave systemsĬurrently, the National Weather Service provides a range of wave heights (i.e. Some users may only be interested in short period waves because they present hazardous, choppy waves for smaller boats, others may take particular interest in the long period waves given the shoaling hazards they create near shore, while others may be interested in both. In the summer we often see short period waves from the SSW associated with the local winds, along with small SE swell associated with the offshore Bermuda High Pressure area. For example, during the fall, we often see short period waves from the NE that develop behind cold fronts, which simultaneously exist with longer period waves from the SE from tropical systems. In addition, it is common for there to be multiple, coexisting wave groups that coincide at any given point in the ocean. The period is also directly related to how fast waves move, how deep they extend into the ocean, how much energy they contain, which, in turn, influences the size of breaking waves at the coast, and more. Wave height generally refers to how tall a wave is from trough to crest, wave direction is the direction the wave is coming from, and wave period is the time it takes for successive waves to pass a fixed point, such as a buoy. There are three fundamental properties of ocean waves: height, period, and direction.
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