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Reposted by Dr. Eric J. Fielding, PhD

Simeon Schmauß @stim3on.bsky.social · 4d

Last night, NASA's Perseverance rover looked up at the night sky once more, to capture interstellar #comet 3I/Atlas flying by the red planet.

The distance was "only" 0.2 AU or 30 Mio km, far closer than the comet ever got to Earth. 🔭 #3IAtlas

Credit: NASA/JPL-Caltech/ASU/Simeon Schmauß

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Reposted by Dr. Eric J. Fielding, PhD

Simeon Schmauß @stim3on.bsky.social · 2d

No Avi, that Perseverance Navcam picture you posted isn't showing 3I/Atlas, it's just Phobos, the brighter one of Mars' moons.

If you were even half the expert you think you are, this possibility should have been quite obvious and worth mentioning.

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Reposted by Dr. Eric J. Fielding, PhD

Meg Schwamb @megschwamb.bsky.social · 2d

This is complete and utter pompous bullshit. It's telling that of the people proposing it wants to anoint themselves director general when every one of his claims of having discovered technosignature interstellar objects has been debunked by the planetary community. arxiv.org/pdf/2510.01405

arxiv.org

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 4d

I assume the Trump Administration found a way to pay the farmers for the food even if they did not deliver it to the food banks.

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Reposted by Dr. Eric J. Fielding, PhD

Marco Foster @marcofoster.bsky.social · 4d

Mark Kelly: “lf you are undocumented in our country, you cannot get healthcare from the Affordable Care Act exchange. You are not eligible for Medicare. You are not eligible for Medicaid. They’re just making that up. They just like to blame brown people.”

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Reposted by Dr. Eric J. Fielding, PhD

Senator Patty Murray @murray.senate.gov · 7d

Here are all the states Russ Vought announced just today he would be illegally stealing taxpayer dollars from.

Have we ever had a President work so hard to hurt the people he represents? I'm not going to be intimidated by these crooks.

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Reposted by Dr. Eric J. Fielding, PhD

Eos @eos.org · 7d

The government shutdown will halt some federal research at agencies already struggling with staff and funding cuts 🧪

eos.org/research-and...

Science Agencies Shuttered in Government Shutdown - Eos

At 12:01 a.m. this morning, the U.S. federal government shut down. This shutdown comes after weeks of negotiations and pressure tactics failed to bring Congressional Republicans and Democrats together...

eos.org

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 13d

The first NISAR (NASA-ISRO SAR) L-band radar images now released! Early images acquired before NISAR reached the final science orbit. The mountains of Mount Desert Island in Maine, USA, are beautiful. I first visited Mount Desert Island with my family when I was small.
www.nasa.gov/news-release...

NASA-ISRO Satellite Sends First Radar Images of Earth’s Surface - NASA

The NISAR (NASA-ISRO Synthetic Aperture Radar) Earth-observing radar satellite’s first images of our planet’s surface are in, and they offer a glimpse of

www.nasa.gov

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 14d

NASA’s Observational Products for End-Users from Remote Sensing (OPERA) project released the Troposphere Zenith Radar Delays (TROPO) dataset that allows InSAR users to reduce effects of atmospheric propagation delays for improved measurement of ground motion. www.earthdata.nasa.gov/news/nasas-o...

NASA's OPERA Project Releases Troposphere Zenith Radar Delays Dataset | NASA Earthdata

This mission-agnostic dataset allows scientists to enhance airborne and spaceborne radar measurements by reducing the atmospheric noise that can obscure ground motion signals.

www.earthdata.nasa.gov

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 14d

They have now officially released the OPERA Tropo products.
www.earthdata.nasa.gov/news/nasas-o...

NASA's OPERA Project Releases Troposphere Zenith Radar Delays Dataset | NASA Earthdata

This mission-agnostic dataset allows scientists to enhance airborne and spaceborne radar measurements by reducing the atmospheric noise that can obscure ground motion signals.

www.earthdata.nasa.gov

Reposted by Dr. Eric J. Fielding, PhD

Popehat Agitates And Irritates @kenwhite.bsky.social · 17d

ICYMI: Part One of my thoughts on how the “free speech culture” movement contributed to the moment of historical censorship www.popehat.com/p/how-free-s...

How "Free Speech Culture" Is Killing Free Speech: Part One

Blurring The Lines Between Official Censorship And Individual Criticism Built The Intellectual Foundation For Trump's Assault On Free Expression

www.popehat.com

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Reposted by Dr. Eric J. Fielding, PhD

Jonah Blank @jonahblank.bsky.social · 17d

Whoever wrote this @washingtonpost.com editorial has no understanding of military affairs-- and has not been reading two decades of the Post's coverage of the war in #Afghanistan:
♦️There is no way to hold #Bagram without the cooperation of the Taliban, or a Berlin Airlift level of resupply.

Brief 🧵

James Fallows @jfallows.bsky.social · 17d

Insanity.

AKA, official editorial position of the WaPo.

www.washingtonpost.com/opinions/202...

Headline: "A US return to Bagram isn't a bad idea."

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 20d

Yes, that is an excellent animation of the ERS-1/2 time series. Someone should redo it with Sentinel-1 data.

Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 20d

I don't know if they have posted the explanation yet. An official Algorithm Theoretical Basis Document should be included with the tool release.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 22d

That is a very strange texture on the surface of the rock. I would guess that rock has an interesting history.

Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 22d

The OPERA DISP-S1 products do not have tropospheric corrections in the product. They decided to make a tool for generating the corrections separately and it will be released soon.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 23d

What spatial scale variation of soil moisture are you trying to measure? The tropospheric water vapor variation is stronger at the larger scales, with little variation at scales less than 2-5 km.

Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 23d

Yes, the NISAR data will be available to everyone for free when it is released.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 23d

The NISAR satellite is still in commissioning phase, with the planned completion at the end of October. The data will be released during the science phase starting in November.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 23d

I don’t know what you were hoping to measure, but it looks like there is no surface displacement in that area above the level of atmospheric noise.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 23d

Interesting results from looking at the polarization signatures. I don’t know what the phase between the VV and VH polarization indicates. It might tell whether there is a strong double-bounce component of the radar return that means there is an object with vertical surface close to the ground.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 25d

The SAR system records the time of the reflection that is proportional to the distance from the satellite. We can measure height above a reference surface with the phase from two radar images such as SRTM two antennas or the bistatic TerraSAR-X and TanDEM-X.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 25d

A radar satellite sends out a pulse and only records the return during a short time interval that is the expected distance to the surface. My guess is that return is more likely a train or possibly a low-flying airplane.

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 25d

Yes, I see there is a bright radar return with a linear pattern on that Sentinel-1 image, but I don't think it is another satellite flying beneath the Sentinel-1 satellite. SAR range direction is literally distance from the antenna, and only objects with range close to the surface will be recorded

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Dr. Eric J. Fielding, PhD @ericjfielding.bsky.social · 26d

One additional point about Dolphin is that it is not a part of ISCE2 and is independent of the InSAR processing system used to make a stack of coregistered SLC images. The JPL OPERA project uses ISCE3 and Dolphin to make the OPERA DISP-S1 products.

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