nasa

nasa t1_ivktnv7 wrote

Reply to comment by Queasy-Bite-7514 in AskScience AMA Series: We're NASA experts working on SWOT - an upcoming mission that will observe nearly all water on Earth's surface. Ask us anything! by AskScienceModerator

We're not losing water to anything. The total amount of water that is on Earth has been the same since the beginning of time. We have great knowledge on how much water is stored in bodies of water, and how much flows into and out of the various components of the water cycle. For example, our colleagues at the US Geological Survey built this amazing chart: https://www.usgs.gov/special-topics/water-science-school/science/water-cycle-diagrams

However, our knowledge is based on long-term averages. Our planet is living and keeps changing as a function of external forces (like energy coming from the sun) and internal forces (like what humans do with the water). So it's always changing. Also, we're now nearly 8 billion people on Earth, whereas we were just 1 billion in the early 1800s.

So: same overall amount of water as ever, many more people than before, and continuing changes in how the water is stored and moves around between, clouds, snow, rain, rivers, lakes, groundwater, and oceans (CD).

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nasa t1_ivktekj wrote

Reply to comment by kkalmightyagain in AskScience AMA Series: We're NASA experts working on SWOT - an upcoming mission that will observe nearly all water on Earth's surface. Ask us anything! by AskScienceModerator

SWOT will measure over 90% of the water on Earth. SWOT will measure the Earth's surface between 78 degrees south (where Antarctica is located) and 78 degrees north (where Greenland is located). So, it won't see any water located at very high latitudes near the poles. -BH

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nasa t1_ivktb7m wrote

Reply to comment by Blackopsman_21 in AskScience AMA Series: We're NASA experts working on SWOT - an upcoming mission that will observe nearly all water on Earth's surface. Ask us anything! by AskScienceModerator

From space, water does indeed look different. It can be different in color or clarity, but the “roughness” of the water is more relevant for SWOT.

The water can be smooth, like on a calm lake, or very rough, like in a stormy ocean. SWOT will be able to make measurements in both of these situations. -BH

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nasa t1_ivkt0pj wrote

Reply to comment by AllAmericanBreakfast in AskScience AMA Series: We're NASA experts working on SWOT - an upcoming mission that will observe nearly all water on Earth's surface. Ask us anything! by AskScienceModerator

SWOT is the first satellite mission that will observe nearly all water on the planet’s surface. It will measure the height of water in Earth’s ocean, rivers, lakes and reservoirs between 78 degrees south (where Antarctica is located) and 78 degrees north (where Greenland is located).

For water that is on the land, SWOT will be able to see rivers wider than 330 feet (100 meters) and lakes that are larger than about 15 acres. Over the ocean, SWOT will be able to see smaller scale features called eddies that are less than 60 miles (96 km) across. No single satellite has been able to observe all of these features.

SWOT will also repeat the measurements over the Earth’s surface every 21 days, so we’ll be able to track changes over time associated with climate change or population change. - BH

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nasa t1_itr4hzv wrote

Reply to If you lived on a planet in the center of the Milky Way would the nighttime be significantly brighter compared to Earth’s nighttime due to the larger concentration of stars? by bad_take_

FYI, we checked with our exoplanet science team, and here’s what they had to say:

>Yes! It would be so bright, you’d be able to see your shadow on such a planet at night. There would be a lot of old, red dwarfs that are dim, but there would be bright K type stars, too! Your nighttime sky would be packed with stars.

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