White House wants Nasa to slow hunt for killer asteroids in 'baffling' move

The Straights Times ^ | 09/01/2022

[BenLurkin]

The space agency estimates there are about 25,000 asteroids of at least 140m in diameter near Earth's orbit. While the odds of them crashing into our planet at any given time are minuscule, Congress directed Nasa to find 90 per cent of them by 2020.

Scientists have found fewer than half. But for reasons it has not publicly explained, the administration has proposed delaying by two years, until 2028, the launch of an infrared space telescope meant to find those threatening asteroids and sharply cutting its budget for next year.

About 500 times a year, researchers identify asteroids of at least 140m in diameter near Earth's orbit.

They're not quite as big as the 10km to 15km asteroid that led to the extinction of the dinosaurs, but there's more of them and they're harder to find.

Such asteroid strikes happen rarely: The same report put the average interval between them at 20,000 years. Much more frequently, Earth gets the smaller variety space objects that leave their own trail of destruction.

In 2013, a roughly 20m asteroid broke apart about 25km above the town of Chelyabinsk, Russia, shattering windows and injuring more than 1,600 people. Russia also was the site of the most destructive asteroid in recorded human history.

For now, Nasa is still mostly reliant on ground-based observations to spot objects of 140m or more. Officials also repurposed a space telescope, called Neowise, that was originally meant to find planets - but it's only discovered five large asteroids this year.

The Surveyor telescope is projected to have a wider field of vision, allowing scientists to get a broader landscape of nearby asteroids,,, And its infrared sensors will spot dark asteroids invisible to the naked eye.

[Elsie]

Most democrats don’t even know what an asteroid is.

Street cant for hemorrhoid.

[SunkenCiv]

Waste of money, no, pork barrel, yes, anything to grab and hold power. Shelby jumped parties to keep that going for himself.

That’s why we’ve had decades of the go-nowhere ISS, and why the overpriced and dangerous STS continued for such a long while. The unmanned probes exploring the planets and the orbiting observatories have been a relative bargain.

[Lonesome in Massachussets]

If you work out time of the equinox in Meeus's Astronomical Algorithms there is a term for the effect of the moon, which shifts the time about two and a half minutes year to year. The orbital velocity of the earth is about 30 km/second, the displacement of the earth center from the barycenter of the earth-moon is about 4700 km. 4700/30 ~ 157 seconds. This is easily the largest perturbing term in calculation of the orbit of the earth, but well modeled and understood. In Meeus's formula for calculating the phase of the moon there are over 250 parameters, including terms for planets including Jupiter, Saturn, Venus, and Mercury. Meeus is for amateurs (like me). Sophisticated models are far more complete.